Fiesers' Reagents for Organic Synthesis (Volume 19)

!1P ttl

|

: -,

Fieserst

for Reagents OrganicSynthesis

,J

't', '

e "."t,'''

\/OLUME NINETEEN

Tse-LokHo \ational Chaio Tung University Republicof China

,E PUBLICATION \ \\ I LEY-INTERSCIENCE JOIf\I WILEY & SONS,INC. / TORONTO / SINGAPORE / BRISBANE \E\\' YORK/ CHICHESTER / \\/EINTIEIM

PREFACE period. Due to the This volume examines literature of mostly the 1995-1996 extending from proliferation of publications, I have decided not to cite full papers of the series rhosepreliminary communications already included in previous volumes the reagents.Deciding .rnd containing sufficient details for synthetic applications of $hattocoverisalwaysadilemma,butmypolicyistoreportthenewestand work or rrgnificant reagentsand reactions when they first appear.For less significant a later until discussion the delay I might use, new a single en old reagent with rolume.Aslhavementionedpreviously,Ishallstrivetoamendmymistakesin nomenclature of missing important work. In volumes prepared by the Fiesers, the probably for System, CA the or IUPAC the to conform ;ompounds does not always spirit, and same in the is alrangement My reader. lhe sake of convenience to the related that so other each near reagents rctually, I have tried to place cognate Thus' browser' a to available rnformation becomes more immediately T' under grouped are MerSiX other and ezidotrimethylsilane, chlorotrimethylsilane, assembled are ligands modified with near trimethylsilyl triflate. Similarly, titanocenes lrrgether'

tl:'fi ln any form ru .i. cxceptas ( t , ' J r l h e rt h e pr::'nate ,lr. (978) \ d:::...'d to the , r5 8 - 0 0 1 2 , i)

Tse-Lox Ho

CONTENTS

GeneralAbbreviations ix ReferenceAbbreviations xiii Reagents 1 Author Index 417 Subjectlndex 467

vll

GENERALABBREVIATIONS acetyl

,rcac ADDP \lBN

acetylacetonate 1,1'-(azodicarbonyl)dipiperidine 2,2'-azobisisobutYronitrile

.1q

aqueous

.\r Bn Bcrc Bu Bz I 8-c-6

aryl

a-

cyclo

benzyl t-butoxycarbonYl n-butyl benzoyl 18-crown-6 catalytic

cyclopentadienYl Cp cyclohexyl C1 DABCO 1,4- diazabicYclol2.2.2)octane DAST (diethylamino)sulfur trifluoride 1,5-diazabicyclo[4.3.0]non-5-ene DBN N,NldicyclohexYlcarbodiimide DCC I .4-benzoquinone 2,3-dichloro-5.6-dicyanoDDQ JC

DIBAH DMAP DMD DME D\{F D\{PU DMSO dpPb dppe dppf -/Yr

diastereomerexcess diisobutylaluminum hYdride 4-(dimethylamino)PYridine dimethyldioxirane 1,2-dimethoxYethane N,N-dimethYlformamide N,N'-dimethYlProPYleneurea dimethyl sulfoxide 1,4-bis(diphenylphosphino)butane 1,2-bis(diphenylphosphino)ethane 1,2-bis(diphenylphosphino)ferrocene 1,2-bis(diphenylphosphino)propane

F, -

COOMe

F-r

ethYl

F-\-E

ethYl vinYl ether

H\IPA

hexamethylphosphorictriamide

enantlomerexcess

x

GeneralAbbreviations

light hv isopinocamPheYl Ipc isoproPYl iPr kilobar kbar ligand L lithium aluminum hYdride LAH lithium diisoProPYlamide LDA LTMP lithium 2,2,6,6-tetramethylpiperidide 2,6-lutidine lut metal (alkali) M acid MCPBA m-chloroperoxYbenzoic methYI Me mesyl (methanesulfonYl) Ms methYlrhodium trioxide MTO methYl vinYl ketone MVK N-bromosuccinimide NBS N-chlorosuccinimide NCS N-iodosuccinimide NIS oxide N-methYlmorPholine NMO nucleoPhile Nu octYl Ctc pyridinium chlorochromate PCC pyridinium dichromate PDC polYethYleneglYcol PEG phenYl Ph phthaloYl Pht pivaloYl Piv n-proPYl Pr

pv

pyridine

RAMP

quaternary onium ion (n)- t -u*ino-Z-methoxymethylpynolidine

RaNi

RaneY nickel

Ff

perfluoroalkYl

(sl

solid (S)-t -u-lno-Z-methoxymethylpynolidine

a'

SAMP

sens. TBAF ;;t **tO TES THF

Photosensitizer tetrabutYlammoniumfluoride =TBDMS,T-butYldimethYlsilYl 2,2,6'6,-tetamethylpiperidinoxy triethYlsilYl tetrahYdrofuran

:'1?5 :\tFD\ :\tS :. '.

tnrvrPrcPllt \'-\'-\-\'-rcl rnrrghrlsl: tsrlrftoh trat ml!-fo\ra\c

General Abbreviations

TIPS TMEDA TMS Ts A ))))

triisopropylsilYl N,MN,M-tetramethylethylenediamine trimethYlsilYl tosyl (p-toluenesulfonYl) heat microwave

REFERENCEABBREVIATIONS ACR ACS ACIEE AJC AOMC BBB BCSJ BSCB BSCF BRAS CB CC CCCC CEJ CJC CL

Acc. Chem. Res. Acta Chem. Scand. Angew. Chem. Int' Ed. Engl. Aust. J. Chem. Appl. Organomet. Chem. Biosc. Biotech.Biochem. Bull. Chem. Soc.JPn' Bull. Soc. Chim. Belg' Bull. Soc. Chim. Fr. Bull. Russ.Acad. Sci' Chem. Ber. Chem. Commun. Collect. Czech' Chem. Commun. Chem. Eur. J. Can. J. Chem. Chem. ktt.

CR DC

Chem. Pharm. Bull. CarbohYdr.Res. Dokl. Chem. (Engl. Trans')

G

Gazz. Chim. Ital.

H

Heterocycles Heteroatom Chem. Helv. Chim. Acta

CPB

HC HCA

IJS(B)

HuaxueXuebao Indian J. Chem.,Sect.B Int. J. Sulfur Chem', Part B

JACS

J. Am. Chem. Soc.

HX IJC(B)

J. CarbohYdr.Chem' JCC JCCS(T) J. Chin. Chem. Soc. (Taipei) JCR(S) J. Chem. Res.(SYnoPsis) JCS(PI) J. Chem. Soc' Perkin Trans. I J. Fluorine Chem. JFC J. Heterocycl.Chem. JHC JNP

J. Med. Chem' J. Nat. Prod.

JOC

J. Org. Chem'

JOMC

J. Organomet.Chem.

JMC

xlll

xiv

ReferenceAbbreviations

JOCU LA MC NKK OM PAC PSS RJOC RTC S SC SL SOC T TA TL YH

J. Org.Chem.USSR(Engl.Trans') LiebigsAnn' Chem' MendeleevCommun. NipPonKagakuKaishi Organometallics PureAPPI.Chem. SulfurSilicon Phosphorus RussianJ. Org.Chem. Recl.Trav' Chim.PaYs-Bas SYnthesis Synth.CommunSYnlett Synth.Org.Chem.(JPn.) Tetrahedron Tetrahedron:Asymmetry TetrahedronLett. Youji Huaxue

ReagentsI

{cetic acid. Alcohols are liberated from the ethers on cleavageofp-methoxybenrylethers,l u arming with HOAc (7 examples, 88-96Vo)' T.W' SC24, 1151(1994)' K.J.,Wallace, Hodgetts,

{cetone cYanohYdrin. Using this reagent as a donor in the Mitsunobu reactton Nitrilesfrom alcohols.r .uccessfully completesthe preparation of alkyl nitriles' C' SC26'909(1996)' \esa,M.C.,Baan,G', Novak,L'' Szantay,

{cetonitrile. 15, 1; 18' 2 pHydroxy nitriles.l

Acetonitrile protonates acyllithium species,which are formed cyanomethyl anion affords :rom RLi and co. Subsequentreaction ofthe aldehydeswith the :he B-hydroxy nitriles. G.W../OC60, 5973(1995)' [-r.N.-S..Yu, S.,Kabalka,

\ -.{cetyl-N-acyl-3-aminoquinazolinones. Secondary amines are not affected by these Acetylationof primary amines,t :!'3gentS. {rkinson,R.S.,Barker,E', Sutcliffe,M.J' CC l05l (1996)'

\cetyl chloride.18,2,

esters Sulfenyl chlorides (RSCI) are formed when sulfenate ftchlorosulfides.r species reactive The chlorides). (or acid other RSOR,) are treated with acetyl chloride functionalizeolefins in situ. Acetyl chloride in combination Deprotection of a-hata aldehyde dimethyl acetals.z (9 examples' 83-98Vo)' aldehydes the u irh acetic anhydride and sodium acetateregenerates Brown.C.,Evans,G.R.TL37'6'79(1996)' :Benincasa, U'M' SC25' 1843(1995)' M., Boni,M., Ghelfi,F.' Pagnoni, 1

2

N-Acyl-2-methylinidazoles

M-Acylbenzotriazoles. Reaction of the activated amides with arenesulfinateanions results in Sulfuxides.t sulfoxides. o-Sulfinyl carboxylic acids are likely the intermediates.

ot l

rlY\n

Ph. I f:C=O l

3h.A

\Z"-lt

,ph

P

h

Ph-s'oNa

2-Acyloxyacroleins. ThesecomPounds Dienophiles.' on enolacetylation and thermolysis of Jienophilesin Diels-Alder reaction5

o

p

Ph-s'

o

,"J

o'

"X"

Y

ocoPh

e p Ph'""""'

t| \ /- 4\ - 1l

h

o I ILen-s,r O . r

75%

I

hydroquinone cH2ct2

\^x I ocoPn

p n p l

I

ot l

o

Funk, R.L., Yost, K.J. JOC 61,2598 t l9)6'

The amides undergo aldolization with ketones and aldehydes, ftI-actones,z furnishing BJactonesin one step.Both transformationsimply keteneformation in the initial step. LDA/ THF, -9f ; R'COR'

Alkenylboronicacids. a-Aminoacids.' A three-comg rcid. an amine,and an u-oxo acid Pmc aaturalsubstitutionpattemareforrnedb

o{>" Ph

E,il.=,""ru

"r*l-o" ".A,'B(oH)z

rKut itrky, A.R.,Yang,B., Qian,Y. SL701(1996). 'Wedler.C., Kleiner,K., Kunath,A., Schick,H. L4 881(1996).

oHc-cooH cH2ct2

Acyl cyanides. Cyanohydrinesters.t Reactionof acyl cyanideswith aldehydesin the presenceof esters. I!CO, in aqueousacetonitrileleadsto cr-cyanohydrin K2CO3

o R1-

JL -cN

+

o H

o c N i l l

CH3CN/ H2O

R2

oo-trt, I h

RlAo

R2

79 - 96/"

Petasis.N.A.. Zavialov,I.A. "/ACSll9. +r5

I -[N-(Alkoxyoxalyl)-N-methylemino a-Ketoesters.' A generalnrtho reactionof the salts.

De las Heras,M.A., Vaquero,J.J..Garcra-\

lOkimoto. M., Chiba, T. S 1188 (1996).

N-Acyl-2-methylimidazoles. Acylsilanes.t Acylimidazoles are electrochemicallyreducedon a Pt cathode,and the ensuing acyl anion equivalents can be trapped with Me,SiCl. rKise,N., Kaneko,H., Unemoto, J. TL36' 8839(1995). N., Yoshida,

Alkynyl triflones.. Theintroducucn Alkynylation.' rhrr is a remarkable skeleton carbon yields good of c-all1n initiator, radical rhe corresponding ethers and adannnu ro give B-trifluoromethylalkyl alkl rrs.

Alkynyl triflones

d iI:

.-::. sith arenesulfinateanionsresultsin ::r' lnterTnediates. n

:tl

Ph, P I

I

Ph

"'oNa

Ph-sn o

l

I

-2-Acyloxyacroleins. These compounds are available from2,2-dimettryl-1,3-dioxan-5-one irroopnwr.l onenolacetylationandthermolysisoftheresultingenolestersatl00o.Theyserveas dienophiles in Diels-Alder reactions'

x" ?

o hydroquinone

ocoPh

\

I

l

n

l

_-;;

iP13SiOry

ocoPh

cH2c12

cHo -,,.- | I focoen

'

i-Prssio^'Z' 105o,20 h

69% p

h

O

//

Funk,R.L.,Yost,K.J' JOC 61,2598(1996)'

: : r./ation with ketones and aldehydes' in the initial tt r- :l Irro\ imply keteneformation

,

-t,O.

-

Alkenylboronic acids. alkenylboronic A three-component condensation involving an o-1,*,roooriar,, having a hoducts yields' good acid, an amine, and an cx,-oxoacid proceeds in uniformly acid' glyoxylic and amines natural substitution pattern are formed by using benzylic

v-o

Ph

80"/"

Hrru\-'on

_:. = CH2)5

'1

,B(OH)2

oHc-cooH

v

I '

Ph{cooH

H2!Pd-c MeOH

NHq

cf

t -

Ph.McooH

HCI

CH2Cl2

).

.9

Hnrl-,oH

78ok(> 99%de)

.rnrdeswith aldehydes in the presenceof

76%(> 99%de)

(199'1)' Perasis,N.A., 7avialov,I.A. "IACS 119,445

-.\ Jnn eslers. .;co3 -,:\

o c N i l l

H20

RlAo 79 -

R2 "/"

-3-methylimidazoliumsalts' ' l' -[.V-(Alkoxyoxalyl)-N-methylamino] " for the synthesisof '-keto estersis by Grignard method A general "-iri" rtrr"r.i :.actionof the salts. Dela-sHeras,M.A.,Vaquero,J'J',Garcia-Navio'J'L''Alvarez-Builla'J'JOC6l'9009(1996)'

{lkvnvl triflones. ,lit ynyUrton.t

tr\ r

. :.enricaily reducedon a Pt cathode,and the . . . . : r\ l e . S i C l . It .s19t 1995).

position tn a The introduction of an alkynyl group to an unactivated

..rbonskeletonisaremarkableachievement'Withalkynyltriflonesinthepresenceofa :rlicalinitiator,goodyieldsofa-alkynylethersorl.alkynyladamantanesareformedfrom rccorrespondingethersandadamantane,respectively.Alkenesmainlyundergoaddition :., eir e p-trifluoromethylalkyl alkynes'

4

ot 1,S-Dienes.zThe couPling Proc€ed 1.1.1-trifluoroethyl)phosphates (cr'1'crosscotr reagents Grignard of :.:r estersin drsc ,r of theallylic phosphate

AllYlbanumreagents

\

d

.

/

o..

oti-rn

) o)-----pn

(Peroxide) ,

*;

cFs

90%

tnflonesby be madefrom alkynyl can triflones The(Z)-alketyl triflonesareavarlable Atkenyttrifl'ones'z co;lins' s";;;;;olk"t'vt followel;;'* the additionof HI c-H bonds' from orsanocolt::]:?ti:illes alsoinsertinto unactivated ntt dienYl and AlkenYl (1996)' rr':^.q.1..Fuchs, P'L''/ACS118'4486

(Iee6)' tt r18'I Ie86 'iil"?];..?,iJ;"tl'-'ro

withBuLi anl atdehvde' treatment Allenyln-butyltttt:11;oorrr.' ^"-' 1 successive on laftercompound' i"^*rirargytic attoho':'_-^..::"'::,.*;; propargl r;;;" to the a as group its allenyl ,rr"*ilt il" t'un'i""

K ' Yasue'K ' Y A'' Ogasawara' ) rnagisawa, H 5I Yamamoto' t;;';;;' e', Yi'o"' K''

carbonate' Ulvl benzotriazol'l'yl Mixed carbm carbonates't AllYl reagent in the pre :repared from this :v-eierentiallY' H'' Tel T., Yamada'H'' Tsukamoto' ii.:rr-ada.

acid dc {ltvlboranes and allylboronic of method One PreParation'r a lic alll of ?J, 0 t-catalyzedreplacement

526(1996)' rDabdoub, M'J''Rotta'J'C'GSL oxide' " hydroxylamineto the allenylphosphine Ailenyldrphenylphosphine ^'"'i|'in'o*rateil "ttini"itt addition The ketones' oximes'r ot usedto olefinate ketones't cr-phosphinoyl of oxidesaffordsoximes

o \"-'ftn,

NH20H

Holi ? PPh2

"D

cHCl3

(1)

allllauo Atlylation' y-Selective allyldiisopropo and esters ::\rm tartrate folloss a ::action with allylic silanes are obrrar r.nd. and primary alcohols

740k

1289 (1996)' Rodriguez' E' TL31 '

^*'^fiff#;:ll';,1'T"T-T."*1"::^-:"'"T;."0J'*1ff1:*'*'orthe 2\-.Bcl2

N-arenesulfonyloxy

Ph

MELi;

,\

J'M'' lPalacios' F', Aparicio' D'' de los Santos'

+:'-t:t

AcO-

MqSi'\/ +

s

with orgar group of the reagents

F'' Genet'I'P'JOC lGreck,C', Bischoff'L'' Ferreira'

Ailvlbariumr3tillr.,

ffi'7010(1995)'

* rortheaddition

]-ltl^t#[i '",t_;:; rhe t"" regioselectivitv aretorr Homoallylicamines'temneratures. lAdducts tempe reaction on hnes is dependent .""*";;" areobtainedat 0'' cr-adducts whereas

"lt;li

N It l.hivama'T.. Ahiko' T" MiyauraA SL ij"t*o,o. Y.. Hara'S ' Suzukr' Zrang' Z tt"tf.,*, D.A', Waller' S'C"

Allylboranesandallylboronicacidderivatives 5

-i

l,S-Dienes." The coupling of allylbarium reagents with allylic bis,1.2,2-trifluoroethyl)phosphatesproceeds at d and c,' positions and is thus different from rhat of Grignard reagents(c,y' cross coupling). Hence, little transposition occurs with the use of the allylic phosphateestersin thesereactions.

\

:*':re -

o)-Ph /

3 -

900/"

rl!-. :.r'. ran be made from alkynyl triflones by i-: : 'nre other alkenyl triflones are available n:

A., Ogasawara, K., Yasue,K., Yamamoto,H. CC 367(l99fi). . \'anagisawa, -\'anagisawa, A., Yasue,K., Yamamoto, H. 5L842,1996.l.

.{llyl benzotriazol-1-ylcarbonate. Allyl carbonates.' Mixed carbonatesderived from carbohydrates are readily preparedfrom this reagentin the presenceof Et.N. Pri-ury hydroxyl groups react

..:.:-(t\3t€dC-H bOnds.

preferentially. Harada,T., Yamada,H., Tsukamoto, H., Takahashi, T. JCC 14,165(1995). Fri.' . i' treatmentwith BuLi and an aldehyde, F :.,:!) I residueto the latter compound.

D, t

:\ dro\J-lamine to the allenylphosphine .rrrch may be used to olefinate ketones.

Allylboranes and allylboronic acid derivatives. Preparation.r one method of preparation of allylboronates involves Pd(0)-catalyzedreplacementof allylic acetatewith bis(pinacolato)diboron (l).

q

P

o

,t - ) t:''

500, 60 h

-: t. E TL37.1289(1996).

L-

:r j

t :1:

:irn(L*opP€r COmPOUndS.

by

-Vo.

-J ,B-_\ / v r Ph

89%

Allylation. y-Selective allylation of aldehydes using chiral reagentsformed in situ irom tartrateestersand allyldiisopropoxyboranes2shows 37-85vo ee.on the other hand, the reaction with allylic silanes follows a pathway leading to hydroxyallylation of the double

t, .::

-

P{-

.V-)

l

ON

iormed

o (1)

HON

MeLi ;

(dba)2Pd/ oMSO

B-B

the

displacement

rcnd, and primary alcohols are obtained from 5-silyl- I,3-dienes.3

of

the

-ill() Hr |1995).

h::..:r ior the addition of y-substitutedallylic -78o, tn ::-rsratures. Y-Adductsare formed at

Me3Si\_^

A-.ao,

-

(,

-450 H2O2 - NaOH THF

.l;hi;"ama,T., Ahiko, T., Miyaura,N. ZZ 37, 6889(1996). -\'amamoto, Y., Hara,S.,Suzuki,A. SZ883(1996). Srngleton, D.A.,Waller,S.C.,Zhang,Z.,Frantz,D.E., Leung,S.-W.JACS119,9986(1996).

6

Allylmanganes€reagents

complexes. 1ql-Allyl;dimethylgold in a Y- and These allYlating agentsreact with aromatic aldehYdes Allylation.r ant i - selective manner.

OH

'cN

: Ph"\,\

+

t7...rt^(

coDs rt

PPh3

' r-Allyl)palladium chloride diu With a bidenure Alkenes.' rromotes the addition of carbon :nuamolecular reaction which fom

OH

*

l pn'\r\

l

t

Phs\

OR OEt

*

t,,.$ot'

Phsq

(84:16) 927.

tSone, 68' 1523(1995)' A', Komiya'S' BCS"/ N.C.,Fukuoka, T.,Ozaki,S.,Kasuga,

? ' ?

"^.v)ft Allylindium reagents. with propargylor Carbonindationof allcynes.r Thereactionof allylindiumreagents to (E)-allylic or leading homopropargylalcoholsshowsregio- and stereoselectivities, -homoallylicalcohols.

lrnr*.

-

/X'

,) rx*

={ax*

,i2-o{

t

R = TBDPS

Hy dr osilYlativ e dim erizttiot with good sterem ..-l-butadienes

:roducts are isolated after Grigna

lillenol

.

SnBu.

BF3. OEt2 PhM€, -7d

OH 9PMB

ZJ

,^

t

l ( > 9 9: 1 )

OPMB

'-.tone acts as a scavengerfor the free I R ., , -CH.CH-CH,) such that extrusion of - ::rr;ell1 useful process.In other words, l \ t. .

1.. ::,.,mbrnation are suppressed.

SnBur

\>

9H

BF3. OEt2 + PhM€, -7d (13 : 87)

a\

gPMB

l0

Aluminum

of aldimines with allyrtributylstannane Homoarylic andnes. The reaction l0 t ,, : ^ l:*^, chloride dimer' catalyzedby Me3SiCP and by the r-allytpalladium

K;;

il;;irronri.rro*

and estefsform N-allyl sulfonamides andazidoformate .

reactions (using carbamates,respectively, in the free-radical allyl donor)."1

.--^rr -U-I-IJ ph,SncHrcH:cH, nr

a a fthe he as

rWeigand,S.,Brtickner,R S 475 (1996)' tl-uni,nir,Y., Planchenault, D' ? 51' l2O9'7(1995)' 'ftun"rri*, S.,Yang,H'' Schaum' R' JACS118'2507(1996)' 4Nug-o, H., Azuma,Y. C' 845(1996)' tC.irt"r, rnl',Audergon,L', Moufid' N ' Renaud'P' TL37' 6335(1996)' 6Ki., s., Kim, s.H. TL36,3'123(1995)' A'B' JACSlll ' 6619(1995)' TEvans, D.A.,Dart,M'J',O"ffV,l'i ' V""g' M'G'' Livin-gston' tNukurnu.u,H., Asao,N', Yamamoto'Y ' CC 1273(1995) (1995)' eWang, D.-K',Dai,L.-X', Hou,X'-L' TL36'8649 toNutunluru,H., Iwama,H', Yamamoto'Y CC 1459(1996)' rrDang,H.-S.,Roberts, B'P'JCS(Pl)1493(1996)'

Alumina.14,20-21;16,9-10; 18, l6-17 decomposeat room temperature to Aroyldiazomethanes'r Diaroyldiazomethanes of alumina' generatearoyldiazomethanesin the presence Wittigreactions..Thesynthesisofunsaturatedestersisconvenientlyperformed. of

;;';;;;'.'

otr,t:ffi;;;;t)"-;;

t rwofold N-alkvlation I--11ttT'T' ^,i':-,:::::::"' rhe ;" basic aluminaat 150' forms N-arvlpiperazines'

the reactlon' N-protecting group is also removed during procedure for the acylation of aromatic irnproved An acylation'4 Friedel-Craf* presenceof (cF.CO)rO on an alumina surface' ethers is to carry it out with acids in the

yosiMes ,/

E

A

r,bt THF .

\:rr:rna, J.M., Sehgal,A., Gogia. A.. \laru :::'-rah. B., Prajapati, D., Sandhu.J.S. Il Jl : -l* in, J.E.,Adlington, R.M., Crouch.\ | ' s n.'1.E., Paugam,J.P.,Nedelec,J.-\',. Fa ..nntieux, T., Picard,J.-P. OM 15. ldX

rluminum bis(trifl amide). .4cetylation. The triflamide is i :r(.:r()lsand aliphatic alcohols( l0 erat r; tnt-latesare also effective.

are rapidly Aromatic carbonyl compounds and imines

$.rminum chloride. 13, 15-17: 14. ll 4.cylation. Some notewonhl .. . -., 'ro-o.-allenylketones,l phenll r - ,nentenones.3

convertedtol,2-diolslandl'2.diamines,2respectively'withAl-KoHinmethanol(AnCHo' 12 examples' 65-937o'' ArCH:NAr" 15 examples, 52-93Vo; ArCOR' 9 examples'

;?

AcCl/ Alols. cH2cl2,-600

65-90Vo)' with sulfones undergo reductive elimination Trisubstitutett allenes.3 hopargylic '74-927o)' AVHg in aqueousTHF (11 examples'

J Al-Hg

'CN

r1 r:nti. K., Kotera,O.,Motoyama. \'.. Sd

rKom"eu,S.,Richter,C. S 1248(1995)' tltuuA", o.o., Sindkhedkar, M D', Mali' R'S' "/CR(s)414(1995)' 'vfi.t ""i, 8., Dence,C.S''McCarthy'T J ' Welch'MJ' TL37' 319(1996)' aRanu,B.C.,Ghosh'K., Jana,IJ'IOC 61^'9546(1996)'

Aluminum. 18, 17-18 l,2'Diols and 7,2'diamines'

Reductivealkylation of s tyrencs.' reductivealkylationof s :..'ctrochemical .: the B-carbon.If proPer cl98% de)

o

11

{ntimony(Y) fluoride. Enones.l Thereactionof l -alkrrr of SbFr. -'.italysis

Nc4-

rlassaletta.J.-M.,Femandez, 8., Diez,E. JACS118'7002(1996)' R., Martin-Zamora'

Antimony(Ill) chloride. 18, 25 A catalytic activity of SbCl, is shown in the Pd-catalyzed Conjugate additions.r transfer of an aryl group from NaBPho or ArB(OH), to enals and enones. The former reaction, involving NaBPh4, proceeds via PhrB-PdPh and is suppressedby a phosphine.

\

-crH,,,

Hayashi, A., Yamaguchi, M., Hirama \1. 5[

Antimony(V) fluoride

asymmetry b;r-c:r.. r I I induces high degreesof

'Cho,C.S.,Motofusa, S..Shim.S.C'JOC60.883( 1995). S.-1.,Ohe,K.. Uemura.

z\

l(;

Antimony(Ill) ethoxide. Carboxylic esters containing polyamine units undergo MacrolactamiZation.l preorganization with Sb(OEt)r. Based on the ready preparation of by facilitated cyclization by this method in 90Voyield, synthesisof several lactam l7-membered phenyl-substituted a and verbascenine) is achieved in a (verbacine, verbaskine, spermine alkaloids

/ \

straightforward manner.

1

..:Jer is also an excellentcatalyst'5

*r1 '..

t,oyP tr"

iq95)

t

I

ll^ llI

However, the reaction employing AIB(OH)2 can be induced by a wide range of catalysts; thus, besides SbCl' other metal chlorides, such as TiClo, AsCl' and, to a lesser extent, BiCL, AlCl3, SnClo,MoClr, and CeCl' are active.

YT" pti

l . l 5 r1 9 9 4 ) . -r lq)5).

sb(oEt)3

*J_^

tT'.--/)

^ PhH

\,/

''oYo J-r i* >T T..--l pt( \.,' eo"/"

t -

||

ll

r formaldehl-de hYdrazone' acts as 1.. t:::l.ite as catalyst, the hydrazone of s. '.-: :rethod is valuable for the synthesis

o.

'X"" (

A

>'\ ir--\ c

\J )--ry" P h t t

r--\ "\-NH I ^

/

)

^ [

( \-.'-"\.. tl /

P

h

\//l

o.

\\--1\

\

pr

/

I,' l\---_\ ] r\ \-/

/

+ +

l

verbaskine

v€rbascenine

'lrhih*u,K.,Kuroki,Y.,Hanaki, H. JACS118'1569(1996)' S.,Yamamoto, N.,Ohara,

r'

O3

,oMe

L*-* )

Antimony(V) fluoride. fumishesenonesdirectlyby the Enones.t The reactionof l-alkyneswith aldehydes catalysisof SbFr.

80". (>98%de)

D '

\

D r e z .E . J A C Sl f E , 7 0 0 2 ( 1 9 9 6 ) '

'CsHrr

SbFs/ MeCN oo, 5 min

o*.,,,, 73"/"

the Pd-catalyzed ic ,-:..rn of SbCl, is shown in The former ' enones' and \:BIOH). to enals l. phosphine' a by g-PdPh and is suppressed .r, t',.

lil

rHayashi,

A., Yamaguchi, M., Hirama, M. Sf 195 (1995).

o-Azidoalkanols

16

Arene(triphenylphosphine)ruthenium dichlorides-ammonium hexafluoroPhosPhate. ofconjugated Cyctoalromntization.r Thesecatalystseffect isomerization/cyclization

o

(> . *f).

dienynestoformabenzenering.oneofthedoublebondsmaybepartofafive-membered probably proceed by heterocycle (furan, thiophene, or N-alkylpyrrole). The reactions elecffocyclization of Ru*- 1,3,5-trienylcarbenoidintermediates'

aY' Y

(cymene)Ru(PPh)C12

NH4PF6 L

OJ

The synthetic utility of this meth 'r ith various nucleophiles to prepar€ :. also possible to form azacyclescoo .i the oxazolinium salts with NaBH.

t-

2,,

c{2ct2

1 0h

{

lMerlic,C.A.,Pauly,M.E.JACS118'11319(1996)'

o

,o) 4-Azidobenzyl 4'-nitrophenyl carbonate' The reagent reacts with amines to form carbamates. Amino group protection.l by reduction of the azido group with dithiothreitol' is accomplished Releaseof the amines undergo spontaneousfragmentation' generated thus The 4-aminobenzyl carbamates

aY*'

fY" ro"-v o

ortt&

Z'-t"N'

RNH2

py / THF 2so, 12h

**VovJo-i o 8a% (R = Bn)

'Griffin,R.J.,Evers,E.,Davtson,R.'Gibson,AE',Layton'D'lrwin'W'I'JCS(P1)1205(1996)'

co-Azidoalkanols. Schmidtreaction.TheLewisacid-catalyzedreactionof2.azidoethanolor 3-azidopropanolwithketonesleadstoamidesorlactams'Thesereagentsobviatethe problemexperiencedbyusingordinaryalkylazides,whichhaveseverelimitations'suchas requiringastrongLewisacid(Ticlr,andevenso'theSchmidtreactionundersuch N-diazonio-l,3-oxazolidine conditions is not general at all. The bifunctional azides form or (R)-2-azido-2-phenylethanol Using intermediates, from which rearrangement occurs. to chiral rise gives (2R,45)-4-azido-2-pentanol,the reaction with 4-t-butylcyclohexanone lactams.I

)

+

BF3' OEt2

/ t \

N3

Gracias,V., Milligan, G.L., Aube. J t.^l Gracias,V., Milligan, G.L., Aube. J JA

or-Azidoalkanols

irkr rides-ammonium

. *f-\o'

conjugated s !.:: -', t r\omerization/cyclization of five-membered a of ^..' part be may bonds : : .proceed by p.:- : . The reactions probably r. .: ::rtcrmediates.

I 1

t-

c'rnr]* ,

.

a-Y\ U,\Z\\ / OJ

)

of the oxazoliniumsaltswith NaBH, gives amines.2

89%

..\ ,

-.,:.t\ $ith amines to form carbamates' Er" ': dithiothreitol' i:.: . 'r of the azido group with fragmentation' rr'. . . .i('rs():pontaneous

reflux

rt,6h

[-\/ I

,^tt1

H 43"k

26"/" (Ar= 3-61-6u60, 61"k

rCaballero, M., Medarde,M., MorandelPrado,L', SanFeliciano,A. ZA7, 1985 8., Puebla,P.,Sanchez, r 1996).

1995)

Slrnrchromate' . rre selectively oxidized to carbonyl lL preparation (927o trri -: rrr-stable powder' Its n r .:r .\ lth CrO, and HCI' TL 36' 8513 .- . -'. .,-\rrto.J.L.,Alvarez-Bu\lla'J'

Lne txtroh!'dride. acid chlorides' . r:..-Jrng conjugatedmembers' reducing agent d l' :. .alr ( I ) is a more selective

Benzyltrimethylammonium isopropoxide. The direct alkylation proceeds in good Atlcylationofa-substitutedaldehydes.' r ields. The products were isolated as 2,4-DNPs (11 examples, 60-100Vo). :Valenta, Z.,MaGee,D.I.,Setiadji,S. JOC 6I,9076(1996).

Beryllium chloride. Highly selective demethylation of AroMe in refluxing toluene is Dealkylation.t gives (17 examples, 90-95Vo). For example, 2,4-dimethoxybenzophenone 3chieved yield. in 907o l-hydroxy-4-methoxybenzophenone F. T 52, 13623(1996). Sharghi,H., Tamaddon,

l.l' -Bi-2,2' -naphthol (BINOL) aluminum complexes. The complex, prepared from i-BurAlH and BINOL in THF at Michael additions.' ,)' followed by treatment with BuLi, is an excellent catalyst for asymmetric Michael and rendemMichael-aldol reactions.

I

I

3Ha

I 1

or\ I!--,

: -lll(rn

Y' F'

t . -

,'
\_-r-td'o

Ho..-,(.-,oH

+ Phclro

75"/"

rWilron,N.S.,Keay,B.A. TL37, 153(1996). 2wilron,N.S.,Keay,B.A. JOC 61,2918(1996). 3cheprakov, I.P' JOMC 486'297(1995) N.V., Beletskaya, A.V., Ponomareva, aTenaglia, A., Kammerer,F. S4 576(1996).

H etero Diels -AAer reactions.: r i. . rs able to promote the condens Cbisenreanangement.6 -:!-:1()n.

Thc

BisOrnzonitrile)dichloropalladium(II)

ethers c.:: ': Gngnard reaction of cyclic allylic -indenyl)f ra. : :hr Ienebis(4,5,6,7+etrahydror'T1l\':.rnt svnthetic intermediatesis achieved' A' TL36,789'7(1995)' l. i ' :irani-Ronchi, r . l r x l - - 9 (1 9 9 6 ) .

N,N'-Bis(alkoxycarbonyl)- 1,3-propylenethiourea. The reagents (1) are donors of alkoxycarbonyl groups for amines. Carbamates.' Thus, N-Boc and N-Cbz derivatives are readily preparedin refluxing dioxane (7 examples, 65-97Vo\.

s

-3'

*n ,,r'A/ 30 min

(97 : 3) 83%

\ rmamoto,H. SL 841 (1995)'

1l

I i I . 136; 14,35-36" 15,28-29; t6'

and aliphatic rx':- , .:ir l ethersof both phenolsr acetone' aqueous in (MeCN), .'l PdCl. 6'-". do not conditions reaction the that l.:^ : :'\!ePt . l l f e r r e d u c t i o n ' r:. CO in s\.::..\t\ of aroic acidsunderatmospheric sulfate' q:. ..::. J,YJecYl allylic alcohol !..- .,: ,iisplacementof a cyclic

*

Utt

with the r . 't an allytic Grignard reagent ^Y-carbon' H. - r:'.lcrat the

ao"NAl,lgo"

(-,

A 7h

Q*"*

(1)

'Matsumuta, N., Noguchi, A., Kitayoshi, A., Inoue, H. JCS(P1) 2953 (1995).

Bis(benzonitrile)dichloropalladium(Il). 13, 34; 15, 29; 18, 46-4'7 A route to functionalized enediyneshas been developed; it dependson Enediynes.' the cross-coupling of chloroenyneswith 1-alkynesby PdClr'(PhCN)t, CuI, and piperidine. Insertion of C:O into silacyclobutanes." Acid chlorides react with silacyclobutanesto form cyclic silyl enol ethers or 3-(chlorosilyl)propyl ketones. Imines undergo [2+2]-cycloaddition with ketenes, which are a-Vinyl-placnrns.3 generatedin situ from triallyl phosphateand CO by a carbonylation-elimination pathway.

Phcocl

*

rSiMer | |

(PhCN)2PdC12 Ei3N / PhMe goo. 4 h

tn _r,o-r,"", \-j 970/"

SnCl, couple transforms an 2-Methylene-1,4-alkanediols.a The PdClr'(Ph6N)z .illylic alcohol into an allyl anion equivalent. 2-Methylene-1,3-propanediolcan be used to Drepare2-methylene-1,4-alkanediolson reaction with carbonyl compounds.

9OOMe - SnCl2 (PhCN)2PdC12

r.';.:'t -edc12

Ho.._,.J{.,.,2.oH t.,i - :

b \l

25:

+ PhcHo

i l ? H to.-\r\"n

DMF, rt

24 h

i, to\tc M.29'7 (1995)

73%

Hetero Diels-Alder reactians.s A related cationic complex Pd(dppp)(PhCN), BFr), is able to promote the condensationofdienes with aldehydesto form dihydropyrans. TIte anti-selectivity is in contrast to the purely thermal Claisen rearrangement.6 :saction.

N

Bis@enzyttriethylammonium)tetrathiomolybdate

-collidine)iodine(I)salts"15.. 8rs(syrn 1,n-Diols.' 2-AlkenYl-l,3dio derivatives.As1'mm Jioxacycloalkane Thus,opticallyactive1,4-andl.5drol hasbec :ormalsynthesisof solenopsin

o,\'( t l

PhMe

1ooo

11

(PhCN)2PdClz

90

10

:

(coll)2lClO.

G' SC26'2831-(1996)' lMlud"nouq M.,Alami,M'' Linstrumelle' l5' 1524(1996)' oM M' 'i-""J Tanaka, n".ashita,H., (1996)' 3zhou,Z.,Alper, H. JOC61,1256 '"no;r;t;^,i', Kagawa' M" Kurusu'Y' cc 1585(1996):TL37' 6351(1996)' 5Oi,S.,Kashiwagi, f'' f"tuAu'p" Ohuchi'K'' Inoue'Y ' (1995)' 6Sugiura, M.,Nakai,T' CL69'1

MeOCH2CHPH CH2C!2, '7*-> a

Cyclic silyl ethers.'

Alkenl l sr

,nalogues.

Nfl'-Bis(benzyloxycarbonyl)'S-methylisothiourea' Guanid.ines.'rt,emett,vrtr,iogroupofthereagentisreplacedonreactionwithan amineatroomtemperatureinasystemthatcontainsHgC!andEqNinDMF. rchundrukurn*, N'S'SC26' 2613(1996)' Bis(benzyltriethYlammonium) tetrathiomolybdate' Reiluctions.'NitronesandN-oxidesaredeoxygenatedby(BnNE!)2MoSo'Acyl azidesgiveamides'Alkylazidesundergoahomocouplingreactiontoformimines'whereas eliminationof andaryl u'id"''-ond"'go reductive stabilizedazides,suchas acyl' sulfonyl' Nr''

.--:^L^^ ri."lfi.lpc furnishes disulfides' Reductive coupling of thiocyanates reactron'' macrocycle by an intramolecular

PhCH2SCN

D ifunctio nalization of cYcloPc*

.minocyclopentenol completesthe fin : the cis-1,3 functionalities is initi ,r nr-collidine)rI+ClO 1.

-V-t^

(mll)zlCloa

),*^

ccl3

NaHCO3 MecN - H2o

i n c l r r d i n q those those containing a including

(BnNEt3)2MoSa -;-e^. PhCH2S-SCH2Ph 88o/"

by exposing the amides to thioamides is accomplished Thioamides.a conversion of reagent' salts to the tetrathiomolybdate coffesponding chloroiminium the selective removal of the salt' this of with the use Cleavage of p*po'sy; )';'*t from allyl' benzyl' and affecting other esters derived propargyl group is possible without

i -rroka, H., Kitagawa, H., Nagotimi. \' . I l:Iaku. K.. Shinokubo, H., Oshima K f - dibrd. B.8., Carreira,E.M. JACS l17.

Bisr I J-cyclooctadiene)nickel(0).

13

::, 18.49-50 Cyclaailditions. TheNi(0){al 'crerocycles in a novel and effrc . .:loaddition with electron-deficieni . TllS) can form [2+2]-cycloadduc

alkyl alcohols. S' ?L 36' 4881(19:5];^ l[ankumaran,P., Chandrasekaran' S' JOC ffi'768^2(1995)' 'i"-"t*, Chandrasekaran' S', Bhat, O.*., (1995)' 3hubhu,K.R.,Ramesha, e'R', cn-atuttkaran' S' t^o'^9'7142 (1995)' 8311 4lantkumaran, e'n', ctt*otut"taran f,f!-]0' P., Ramesha, (1996)' 1957 CC S' sllankumaran' P.' Manooj,N'' Chandrasekaran'

ll

u"r":-2t

NTs

N(codh

(Aro[P ' r]f rt

Bis(15-cyclooctadiene)nickel(0)

U-

Bis(sym-collidine)iodine(I) salts. 15, 3O; 17, 155 ; 18, 49 2-Alkenyl-1,3-dioxolanes undergo ring expansion to give 1,4I,n-Diols,' dioxacycloalkane derivatives. Asymmetric induction occurs in the casesof chiral acetals. Thus, optically active 1,4- and I ,5-diols can be preparedusing this reaction as a linchpin. A formal synthesisof solenopsinhas been accomplished.

89

Pl'l

't0

'J

t

Ph

C lrr l': I r 1996). .' j +)6). , !..

Ph

(collhlCl04

d'-ro

MeOCH2CH2OH cH2cl2 , -7go->rt

u/\'/\/

$,

OH

o,..\_-/." OMe

lr. -: \ rL37.6351(1996)' Cyclic silyl ethers.z lothiourea. on reaction with an tF : ire reagent is replaced DMF' in r! - ::rrns HgCl and EqN

ph

'.J d t o

9O7o Alkenyl silanols cyclize in the same manner as the all-carbon

analogues. Difunctionalizationof cyclopentadicnes. The stereoselective elaboration of an Introduction aminocyclopentenolcompletesthe first stageof a synthesisof (+.1-trehazolin.3 with of a trichloroacetimidate of the cis-1,3 functionalities is initiated by a reaction , qvn-collidine)2I*ClO ;.

Frolr Mate. (BnNEt )rMoSo' Acyl 0.. .,. deorygenatedby whereas 'to t()upling reaction form imines' r.? of elimination reductive ar j .,:, . azides. undergo

-v-t^

(collhlClOa

U ,*1"","

NaHCOg MoCN - H2O

N H

those containing a lu:: ':c. disulfides, including

f:. -'.'S : : PhCH2S-SCH2Ph

' throamidesis accomplishedby exposing the r!r : r: :.l:nlomolybdatereagent' removal of the ,,,. ,..' u* of this salt, the selective .. from allyl' benzyl' and lc-: - ,'ther esters derived

,:..

s . r3: \ d--ri:.

.45

I.

-68? ( 1995) 60. ,i()C60.7142(1995)' . It 3,6.831I ( 1995)' (a1957(1996)'

(+)-trehazolin Y. JOC 61,7309 (1996). .Fujioka, H., Kitagawa, H., Nagotimi, Y., Kita, "Takaku. K., Shinokubo,H., Oshima,K. TL37,6781 (1996). 'Ledford. B.8.. Carreira.E.M. "/ACS117, l l8l l (1995).

f 3, 35; 14,36-37; 15,30-32, 13l - 132; 16,29; 17, 8ls(1,5-cyclooctadiene)nickel(0). :l: 18,49-50 generates intramolecular Cycloadditions. TheNi(0)-catalyzed [4+2]-cycloadditionr :.cterocyclesin a novel and efficient manner. Norbomadieneundergoes[2+2+2)(e.g., norbomadienes alkenes,while somesubstituted :rcloadditionwith electron-deficient :.T\4S)canform | 2+21-cycloadducts.2 r,-\'-1 ll

M""s:2-J

NTs

Ni(codh

(Aro)3P/ THF rt

NTs

DDQ dioxane

30

Bis(1,5'cyclooctadiene)nickel(0)

o '=o

-h tr{

Ni(codh - 2 Ph3P

l

>

ctcH2cH2cl, 8d

/t..-i' l

F&alkynyl epoxide is

ia. -:-r'r.rted by epoxide cleavage adds to the r!-:r.: ihr\ processas an annulationstep.

Bis(2,2,2-trifl uoroethyl) alkanesulfinylmethylphosphonates. (Z)-Alkenyl sulfuxides.' The reactionof RS(O)C[LP(OXOCII2CF3),with aldehydes r. highly stereoselective.However, the correspondingsulfenyl reagentsshow a trend toward rhe formation of (E)-isomers. Thus, for the synthesisof (Z)-alkenyl sulfides. this method is u'eful in view of the fact that deoxygenationof the sulfoxides with BurP-CClo proceedswith retention of configuration. S. S 637(1996). J.,Hayashi, Kokin,K., Tsuboi,S.,Motoyoshiya,

L, ceratopicanol

J.TL37,4357(1996). J .:..'-,sr.R P..Schwartz,

Bis(2,2,2-trifl uoroethyl) 1,3-dithian-2-ylphosphonate. The lower basicity of the anion derived from (1), compared with Homologation' rhat of the dimethyl phosphonate,is useful for homologation of ketones containing acidic a-hydrogens, including cyclopentanone and p-tetralones. The products are ketene lithioacetals.

I

i. -rr ll- r 1993).

r^s

PF.

(^A^,o-r

/.fr^ / u-

o t .:

bt,

(1)

r. L\-

:r.r:hler reaction of an organohalogen , :. I go(d methodforthepreparationof

u-

.'::,'r,l esterswith (Bu.Sn)rO in THF at

G. SZ875(1996). \link, D., Deslongchamps,

Bis(trimethylphosphine)titanocene. Reductive cycliZation.t'2 Unsaturatedcarbonyl compounds having the double bond .jr a remote position give cycloalkanols when a hydrosilane is present.

42

Borane

Fused lactones.3'4 The foregoing reaction is diverted toward the formation of lactoneswhen Co is added instead of a hydrosilane'

/--to \ ."--\

Cp2Ti(PMe3)2 pentane 2 5 0, 2 h

ff,.', 19€X',

air

/^--f

O,

( l F o \------w

91"/"

Pauson-Khnnd-type reaction.s Titanacycles formed from enynescan be converted to N-silylimines of bicyclic enoneson reaction with RrSiCN. rKablaoui, S.L.,IACS118,3182(1996). N.M.,Buchwald, 2cro*". w.E.. Rachita.M.J. JACSll7 ,6787 (1995). 3C.o*., W.E.,Vu, A.T. "/ACS118,155?(1996). aKablaoui. S.L.JACS118,5818(1996). N.M.,Hicks,F.A.,Buchwald, 5Hi.kr,F.A.,Berk,S.C.,Buchwald, (1996). S.L.JoC 61,2'713

Bis(trimethylsilyl) chromate-silica gel. The reagent is generated from CrO, and (Me.Si)rO in CHrCl, and Oxidation.r supportedon silica gel. It has similar oxidizing power toward alcohols as do other chromates (22 examples,7 | -99Vo). 'Lee,J.G.,Lee,J.A.,Sohn,S.Y.SC26,543(1996)'

chromate. Bisltrinitratocerium(IV)l Refluxing the silyl ethers in benzene with this Oxidation of trimetfutsilyl ethers.l (8 80-92Vo). The reaction is sluggish when products examples, reagent affords carbonyl is used. trinitratocerium(IV) chromate dihydrate rFirouzabadi, H., Shiriny,F. SC26, 649(1996).

Bis(triphenylphosphonio)oxide bistriflate. 18 In refluxing dichloroethane in the presence of triethylDienesfromepoxides.t amine, epoxides undergo a double-elimination reaction, giving conjugated dienes in good yields. Crowded epoxides remain unchanged; thus, the mixture of cis- and trans-cyclododeceneoxides affords a clean mixture of (lE, 3Z)-cyclododecadiene and trans-cy clododeceneoxide (50Voyield). lHendrickson. M.S. Sa66l (1996). J.8.,Walker,M.A., Varvak,A., Hussoin,

Borane. 18. 58 7,2-Diarylhydrazines.t 48-88Vo).

Azoarenes are reduced at 0" by BHi'THF (12 examples,

Protection of oxazoles,z l-Lrth alkylation of the heterocycle via the I oxazole-borane complexes behave nc easily removed after the alkylation br \ Activation of Lenzylamines.'

rs facilitated after forming the borane r Phosphine complexes.a Marnrr rn such complexes and enhancenrnt

adjacent carbon enable the enantio:< ;omplex. Oxidative coupling of the :rccomplishthe synthesisof C,-s1'mnr trt1^ 7"J ,F. ' ox' "' ./ \

s-Buli- C)-sParteine / THF cu(opiv)2

.{Iula. M.R., Kabalka, G.W. SC 26. -1E:I t\'.deis, 8., Monahan,S.D. ,/oC 61. 519: 'EMen, M.R., Simpkins,N.S., Fox. D.\.A '\tuci, A.R., Campos,K.R., Evans.D.A .l

Borane-amines. 13,42; lE, 58 Trearm Reductive amination.t

xrrane-pyridine complex in methan .econdary amines. Deoxygenation of aromatb Lar

r. a mild and efficient reagentfor rhi Acetal cleavage.t Interestingl; J.6-O-benzylidene glucose and glttct

rifluoride etherate.is dependenton O

pr.4or o-to, BnO-\--l\ zNH

+ BH3.Me2{ 6u"

Borane-amines 43

a.:. :. r\ diverted toward the formation of fts:::.4

---- o-

Tico,

-\-\"83q.

607.

t:- . - ... formed from enynescan be converted o: .. '.: R,SiCN. l,

protectinn of oxazoles,z 2-Lithiooxazoles are liable to undergo ring opening; thus, the other hand' alkylation of the heterocycle via the lithiated speciesis problematic. On moiety is borane The deprotonation. during oxazole-borane complexes behave normally HOAc' with easily removed after the alkylatio-nby treatment benzylaryLines Activation of benzylamines.3 Metallation at the benzylic position of is facilitated after forming the borane complexes' phosphine complexes.4 Maintenance of a tetrahedral state of the phosphorusatom attached to an in such complexes and enhancement of acidity of the hydrogen atoms the s-Buli/(-)-sparteine by adjacent carbon enable the enantioselective deprotonation the borane units complex. oxidative coupling of the lithio derivatives and removal of accomplish the synthesisof Cr-symmetric P-chiral diphosphines'

r-

9^ ?Lt 'Ph"rR "./ \

11r 90:10). TiCl. has the BCl., by r. renderedsyn-selective .ame effect. (E)-Alkenylsilanes undergo hetero-group exchange on (E)-Alkenylboronates.Z at 0'. Subsequentreactionwith catecholin benzeneat room in CHrCl, rreatmentwith BCl., esters(4 examples,74-897o)' the boronic lemoeraturefurnishes prenylntion.3 Prenyltributylstannane is activated by conversion to the tertiary on reactionwith BC\. Prenylationof ketonesand indole (at Jimethylallyl)dichloroborane It is c-2) is readily achieved. The method is crucial for the synthesis of tryprostatin-B. attaining it from prevents This immediately' be trapped :nportant that the dichloroborane residue) :quilibrium, and, therefore, the generationof regioisomers(with respectto the allyl . avoided.

.- SnBug

- .:rh nrethanolysis),giving thiols, and "'rJ rro rheresin inducesthe formation of r:tcd in situ by alkenessuch as acrylic

-.'/

[

T

,"u --;

"rx

at' l l l \,/-N

lcooEt , / H

65% (overall yisld)

46

Borontrifluorideetherate of propargylit

Homobgation

Lithiation

abohols.a

of

mixed

the

acetals of

propargylicalcohols,treatmentwithBH.andBCl,insuccession'andthentreatmentwith of BCl, are to induce unain" H,o, give homopropargylic alcohols. The functions fragmentation ofthe acetal unit and to catalyzethe alkylation step'

Ph

r

I

I

t - . J , " " .!-t )

/{'o,'#l ,/"^""l*1. l'le. LH H

LaH,

I -I

Ph

r

'/"'/o

NaOOH ////

I

89"/" (overall yield)

rsurko,C.R.,Collibee,S.E',Knon,A.L.' DiMare,M' JOC 6l' 868(1996)' 2Farinola, V., Mazzone,L', Naso,F' CC 2523(1995)' G.M.,Fiandanese, 'O"p.*, K.M., Danishefsky'S.J.,Rosen,N', Sepp-l'orenzino' L' 'IACS118' 12463(1996)' acurri",D., Carboni, B., Vaultier'M. TL36,8209(1995)'

Th [3,3]Sigmatropic rearrangements' hreD requires by BF,.OEt ,5 although it still best. The conversion of N-vinylsulfinylarut .'onditions when BFr'OEt, or EtrCt*Bf igrc Aldehydes combrr 7,3-Oxazlcycles.t presence of BFr'OEt, to give hetera" \lechanistically, the intramolecular reactron
00

MeOOC

Borontrifluorideetherate

. rrhration of the mixed acetals of :' Dd :r\'.. ln succession,and then treatmentwith The functions of BCl. are to induce It: \.'f ':..,rlk) lationsteP.

.Tn l t:; A .oH u '- (i ".'o NaooH ./ \/ 4y' I Ph l

*

- BHz

-i

89"/" (overall yisld)

The amino-claisen rearrangement is catalyzed [3,3]Sigmatropic rearrangements. at by BFr.OEtr,s although it still requires high temperatures,and the yields are moderate milder under effected best. The conversion of N-vinylsulfinylanilines to indoles can be conditions when BF"'OEI' or EtlOBq ispresent.o Aldehydes combine with 1,2- and l,3-azido alcohols in Jhe 1,3-Oxamcycli.T presence of BFr.OEt, to give heterocyclic products (21 examples, 18-967o)' group Mechanistically, the intramolecular reaction of oxonium intermediateswith the azido is akin to the Schmidt reaction. The Lewis acid-catalyzedreaction of imines with diazoacetic esters Aziridines.s seneratesaziridines in which the cis-isomers predorninate' Silylated enyn r.e Condensation of 3,3-bis(trimethylsilyl)propyne with aldehydes provides predominantly (E)-1-trimethylsilylalk-3-en-l-ynes (8 examples,48-60Vo).

r \ 1 ' , ( 6 1 .8 6 8( 1 9 9 6 ) . r- : '( l-sl3(1995). (1996). p' .',:rrnrr. L. JACSll8, 12463

BF3' OEt2

MeaSi

/

...:

xl

Me3Si

-

+

El

Et-cHo cH2cl2 -600'>-2d

quinones. Useful catalysts include polymer-supported vanadium salts7 and (Ph,P),RuCl2.8The Rh-catalyzed reaction can oxidize p-substituted phenols, giving 4-l-butylperoxy-2,5-cyclohexadienones, which undergo rearangement (migration of the substituent)to afford the quinones on treatment with TiClo. (4 examples, The oxidation of 2-allyl-1-naphtholsleadsto 4-allyl-1,2-naphthoquinones 65-73Vo) as a result of hydroxylation followed by oxy-Cope rearrangernent.e

are alll l

reaction with t-BuOO Hindered

rn NMP, followed by TBAF.

:Hursthouse, M.B., Khan, A., Marson.C.V rlanier, M., Haddach, M., Pastor, R.. fuess 'Lakner, F.J., Cain, K.P., Hager, L.P. ./ACj tPalombi, L., Arista, L., Lattanzi, A.. Bqrr 'lyer, S., Varghese,J.P. SC25, 2261 tlcl95 'Krohn, K., Vinke, I., Adam, H. JOC 61.I Suresh,S., Skaria, S., Pornathnam.S. 5Cl 'Vurahashi, S.-I., Naota, T., Miyaguchr. S 'Krohn, K., Bemhard,S. S 699 (l996t. Choudary, B.M., Reddy, P.N. SI 959 | 199 Bhat. S.. Chandrasekaran,S. ?L 37. 35El t.\raneo, S., Fontana, F., Minisci, F.. Rcol '\{iller, R.A., Li, W., Humphrey,G.R. Z, -Raju, S.V.N., Upadhya, T.T., Ponrathnam -snvastava, R.S., Nicholas,K.M. CC 13-1 -smitrovich, J.H., Woerpel, K.A. JOC 51.

o

ff'Y"

>'-a R' Y-

Oxidative cleavage of cyclic acetals.to With VO(OAc)2 as catalyst, r-BuOOH effects the transformation of cyclic acetalsto hydroxyalkyl esters. Reactionof alkenes. r-BuOOH acts as a coaddend for alkenes to give mixed peroxides under certain conditions (e.g., in the presenceof B-cyclodextrin and waterrr or with Cu(OAc)2 as catalyst to generatethe tetrahydrofuranyl o-radical).r2

r-Butyl hydroperoxide-dialkyl tarrn ^ I -62; 15,55-56; 16, 54-55:17. 5'7-: Cyclobutanones.r Epoxidarioo -ewis acid-catalyzedrearrange[rnl ruhnonesarevaluablefor the syntlrsr

,.L,H _ ''

,\Aor". t-BUOOH

PhA

p-cD/ H2o 250, g h

r

OH

p6)(..-ooaut

r

*

OOBur

,nX.-o" (19 : 1) :rkumoto, K., Nemoto, H., Nagamochi. V 86%

t-Butyl hydroperoxide-dialkyl tartrate-titanium(IV) isopropoxide

with oxidation of unsaturated steroids to enonesl3 has been achieved Ti-containing by catalyzed is ethers enol silyl of r-BuooH-RuC1r, and the cleavage results in the silicalite.l4 In the latter reaction, oxidative cleavage of the double-bond

+

Allylic

:J.hromo-2-methylalkenes catalyzed by ::r:.rted somewhat with the molecular

\ :

:\' and other additives, including . zrng the oxidation of allylic and benzylic a : . : :-BuO)rZr6 is capableof oxidizing other . s : . . .LrJepolymer-supportedvanadiumsalts? t. -.:n ()\idize p-substitutedphenols, giving l . -:rJr'rgo rearrangement(migration of the . , : : hT i C l . . frd. L :

: -.,ll\ l- I .2-naphthoquinones (4 examples, - . i,r -Cope rearrangement.e

in NMP, followed bY TBAF. rHursthouse, M.B., Khan,A', Marson,C.M., Porter,R'A' IZ 36' 5979(1995)' 2lanier,M., Haddach,M., Pastor,R., Riess,l'G' TL34'2469 (1993)' 3l-ukn"t,F.J.,Cain,K.P.,Hager,L'P. JACSll9' 443(199'7)' aPalombi, L., Arista,L'Lattanzi, A.' Bonadies,F'' Scettri,A' TL37 '7849(1996)' 5lyer,S.,Varghese, J.P.SC25, 2261(1995). 6Ktohn,K., Vinke,I., Adam,H. JOC 61, 1467(1996). Tsuresh. S. SC26' 2ll3 (1996) S.,Skaria,S.,Ponrathnam, sMurahashi, N., Noda,S' JACS118'2509(1996)' S.-I.,Naota,T.' Miyaguchi, 'Krohn, K., Bemhard,S. S 699(1996). roChoudary, B.M.,Reddy,P.N.SL959(1995). " Bhut.S.,Chandrasekaran, S. TL 37,3581 ( 1996). (1995). 'lAran"o, S.,Fontana,F., Minisci,F., Recupero, F ' Serri'A cc 1399 'iMill"., R.A.,Li, W., Humphrev, G-R.TL37,3429(1996)' 'aRuju,S.V.N.,Upadhya,T.T., Ponrathnam, S.,Daniel,T', Sudalai'A cc 1969(1996) r5srivastava, (1996). R.S.,Nicholas,K.M. CC 2335 r6smitrovich, J.H.,Woerpel,K.A JOC 6L,6044(1996)'

o *o

)
^

OTBS

TBSO

HO'-

o^Ph

B u L i/ T H F - z R o - o- o

)-cl ErO)2Pi cl r.|

Me3SiCl / THF a

HO +,-Ph

I( o r l \ . )/

1

\

/

TBSO

OTBS

4Q%

estersis An intriguing diastereoselective synthesisof cr-hydroxyalkylphosphonate shown below.l5 Chalc ogen -lithium

o ---t-^-f---,,o..,z^...

an7

^ BuLi/rHF. -7s",14h

-2;p,[l* 'k

: H2i HCt;

o"

MeO

i l : -rP-.."r'r".,'

MeO

exchan g c. .'onveniently carried out by the rert :olorless solid that ignites on contr months.

I OH

CH2N2

/

77.

74"k

Q

a"a

-z:su

P=O

f

a"\ t l

I

Br

HO\,/^\r' BuLi/THF -78o,14h

HCI; CH2N2

Hatogen-lithium exchange. With hexane as solvent, alkenyl- and allenyllithiums are preparedl6 by the exchange reaction at room temperature. In ether, the formation of enolatesfrom s-haloketones is possible through treatment with BuLi.rT 0,-Bromoenolates, also accessiblefrom cr,c-dibromoketones by this method, can be used in a synthesis of

A dramatic solvent effect h oalkenylbenzyllithiums, which ar Selenobenzophenonesundergo corr reatment with BuLi.

X"t" (..\

tl o

rnY{rn

PhcHo / Et2o 250

BuLi mediates the silylation and alkylation of diethyl trichloromethylphosphonate, allowing the preparation of l-formylalkylphosphonatesle and 1-alkynylphosphonates.20

a

Ph. ,,

epoxy ketones by reaction with carbonyl compounds.r8

BuLi;

-78o - rt

OH 690/o

Br,

BuTeLi/ THF

Hz;

I '-7-a-P=a ^"N'-
95 : -_J/\/ 'o

\ctslo

Cadmium. 13,60; 18, 83 f,^TUnsaturatedketones.r rcdiated by cadmium. Cleavage of Troc groups.'

Allylation of acid chlorides with allyl bromides is

The 2,2,2-trichloroethoxycarbonyl protecting group of :mines is removed in neutral conditions using l0% Cd-Pb in THF containing NHTOAc (5 :rampfes, 89-94Vo). B., Boruah,A., Prajapati, D., Sandhu, J.S.TL37,9087(1996). Baruah, 'Dong, Anderson, C.8.,Ciufolini,M.A. TL36,5681(1995). Q.,

Carbon dioxide. Carbonates.r

Phosgenecan be avoided in the preparation ofcarbonates by using a :uanidine as catalyst to condensealcohols with CO, after which O-alkylation ensues.The . reldsare quite respectable(7 examples,53-97Vo).

o [Me2N]2c=NCy FPrOH +

BnCl co2, NMP 55o,

18 h

ll 'OBn r-Pro' 85o/o

\lcGhee,W., Riley,D. JOC 60,6205(1995).

Carbonyldihydridotris(triphenylphosphine)ruthenium(Il). (Triethoxysilyl)ethylatinn. Introduction of a silylethyl group to aromatic ketones ind esters at an ortho position is highly efficient, employing a reaction with nethoxy(vinyl)silanein the presenceof RuHr(CO)(PPhr),in toluene.rlnterestingdirecting :it-ectsof substituentson this insertion reaction have been observed.2

o

T -2

(Eto)3si

I] tl

(Ph3P)3Rh(CO)H2 -SilOE\JJs + P h M e ,1 3 5 0 ,3 h

+

si(oE03

R R=OMe

830/"

R=Me

3k

'to"k 93% 65

66

Carbonylhydridotris(triphenylphosphine)rhodiun(D

Ananalogous(B-silyl)ethylationreactionofconjugatedestersandketonesbyinsertion also possible'3'a of tf,. C-ff U'-ondat the p-carbon is N'' Murai' S' BCSJ68'62 lKakiuchi,F.' Sekine,S ' Tanaka'Y ' Kamatani'A'' Sonoda'M'' Chatani'

c^ri.^-----:

+

PhsH +

(199s).

JOMC-504'151(1995)' 2sonoda, M., Kakiuchi'F', Chatani'N'' Mvai'S' S.CL 679' 681 (1995)' Murai' 3Kakiuchi,F.' Tanaka,Y', s;, T'' Chatani'N'' oi-r,, S.M., rrni, K., Davies,I'W "/ACS117' 5371(1995)'

Yrmaguchi, M., Omata, K., Hirama. M. IL Yamamoto, Y., Kubota, Y., Honda, Y.. Ful 3usacca,C.A., Dong, Y ' TL 37,3947 (199 ' )eawa, A., Takeba, M., Kawakami' J.. T1l

C arbonythydridotris(triphenylphosphine)rhodium(I)' the anenes to give (E)-enynes under Enynes.r l_Alkynes uoa-to onu.tivated es' 43-9 lVo)' (2 infl uence of RhH(CO)(PPh,), I exampl

-LCarboxypyridinium chlorochromr Hyd.rolytic cleavage of C:N bot .'nverts phenylhydrazones,p-niuofl -:tluxing dichloromethane to the paret

Ph

S. SC26. I I :leltork,I.M., Pouranshirvani,

a

,dv":

:-Ph

(Ph3P)3Rh(co)H Et3P/ rHF ^

th

a ^A

Ph-

68%

as nucleophiles' use of malononitrile derivatives Ad.ilitian to ilnines.2 with the reactions are performed' synthetically valuable C-C-bond-forming compounds ftil" synthesis of these heterocyclic n 4-Aryl'2,3-dihya,opyooi"S CO into of incorporation catalyzed cyclization and reductive involves Rh

t'atecholborane. 16, 65-66; 17' 674 Aldehydes,r Partial reduction --rperature (15 examples,85-l00ct

:r\'cedure using diisobutylaluminum h Elevated terry Hydroboration ' , Jroboration of alkenes using caterl ', \-dimethylacetamide, which can pn

.:.r.J.S.,Chang,S'W.,Kwon,O.O..l(rm :irrett,C.E.,Fu,G.C.JOC 6l'3224 tl99

N-tosylcinnamYlamines'

(Ph3P)3Rh(co)H

Ph

,,\\\7 n

NHTs

Ph3P- co - H2i

/-T'

Ph--^\,,'

of 1-alkynes rs qftunsaturated aldehydes'a The thioformylation ftArylthio yields the reaction tvteCN at 120o' Usually' the performed with the nn(t) latalyst in proximal a at present group (e'8'' OH) is (Z)-isomers selectively, unless a coordinating positioninthecarbonchain.ThecarbonylationisnoteffectedbyPd(oAc),,whichcatalyzes Pd species in the Markovnikov sense.Phosphine-ligated the addition of thiols to alkynes promotetheformationot**ytyp"'ofproducts'whileNi'Ir'andRucomplexesexhibit no catalYtic activitY.

t crium(IV) ammonium nitrate- 13. .(,)

Carbonylation of triarylsfilbines.te . .o requires CAN.

CAN MeCN

I

cAN - (PnC

fi1'o' =-,^.7.

Phssb

CO. rr.| 2f

2/

70"/"

Nitration of alkenes, including allylsilanes, is accomplished with CAN-NaNO2-HOAc as reagent.lo A three-component assembly of a 2,3-disubstituted cycloalkanonerrfrom an electron-rich alkene (e.g., an enol ether), a 2-cycloalkenone, and another nucleophile is illustfated by the following process in which a l,l-dialkoxycyclopropane acts as a latent homoenolateanion.

\

( r l

o

X;:J'* *

iupta,A.D., Singh,R., Singh,V.K. SL 69 rl99 ilqu. J.R.,Jain,M.L., Tsay, S.-C.,Hakimelalu. i{*ri. J.p., Jain,M.L., Tsay, S.-C.,Hakinrela}u -ir ans.P.A., Longmire,J.M., Modi, D.P. Il f. irans, P.A., Nelson,J.D. JOC 61,76O0r 1996r \:rr. V., Mathew, J. JCS(PI ) 1881 (1995). \lrqnus, P., Barth, L., Lacour,J., Coldham.1..I ' r.:rr. N., Narasaka,K. CL98'7 (1995\. \l:chizuki, T., Hayakawa,S., Narasaka.K. 8C5 :i*u. J.R.,Chen, K.-L., Ananthan,S., Parel.H \ r - , l o b e l l i , A . B . , R u z z i c o n iR , . JOC6l.6f-1{, I >..,lobelli, A.B., Ceccherelli,P., Hzzo, F.. Ruzz :: * u. J.R.,Chen,C.N., Shiao,S.-S.JOC ffi. t:4 \:rr.

V., Mathew, J., Radhakrishnan,K.V. -/C9 r *rayashi,K., Mori, M., Uneda, T., Morikaue \ -rrvarna,T. AOMC 9,399 (1995).

cAN/ MeoHi lroEt '

"q.CF3COOH cHcl3 oo

\^"to n7f COOET 62%

"

rlindal, P.K., Roy, S.C. T 51,7823 (lc]45l :5'rpoor,N., Kazemi, F. S 821 (1996). :.'. C.S., Tanabe, K., Itoh, O., Uemura. S. ./O(

Cerium0V)ammoniumnitrate

ethers r : ::.3 o\idation of triisopropylsilyl enol exposed are F i..:,,. tcceptorswhen their anions I( : -g.rtedketonesareobtainedonsubsequent

In another condensation,r2 l,3-butadiene is used to assemble two nucleophiles, the oxidation in one of which initiates the coupling.

Me3Sio

/> \-, hl: '

Yn

o.

CAN - CaCOa r

\ v

_ \,>#\ t l

MeCN, rl;

^ \

./ E

NaCH(COOMe)2

E

E

(Ph3P)4Pd / THF

Et.ru

C

69

| ? /\Apn

(93 : 7)

E = COOMe

MeoH,rl 98% (basedon silyl enol ethe|

f

-,'ncomimnt with

nng

expansion

of

\i

o.\ Ph../

The CAN oxidation of thesecompounds in Additian to 7,3-dicarbonyl cotnpound* '.he presence of allyltrimethylsilane results in C-allylation.r3 The oxidative addition of I .-i-dicarbonyl compoundsto alkenesto form dihydrofurans is a rather generalreaction.la'r5 2-Oxazolines.l6 cr-Nitro ketones form nitrile oxides, which are trapped by Jipolarophiles. Preparation of sulfur compounds. CAN acts as a catalyst for dithioacetalizationrT .nd the transformation of epoxides to episulfides (using NHTSCN).r8 Ester formation in the Pd-catalyzed reaction Carbonylationoftriarylstilbines.rg .lio requiresCAN.

\ cAN - (PhCN)2PdC12

UeCN

tJ.

CO, MoOH 250, 24h

\/.-2

. :. .rccomplishedwith CAN-NaNOt-HOAc i'Jr:ubstituted cycloalkanonerr from an I -rcloalkenone, and anothernucleophileis ., l. l -dialkoxycyclopropaneacts as a latent

o L:

3 A N .M E O H '

,,YCHO \

PhCOOMe

Ph3sb

/\"::r1soz

I

aq. CF3COOH

'COOEI

CHCI3Oo 62"k

890k

(1996). .Gupta,A.D., Singh,R., Singh,V.K. SL69 'Hu,u, J.R.,Jain,M.L., Tsay, S.-C.,Hakimelahi,G.H. CC 545 (1996). Hwu, J.R.,Jain,M.L., Tsay, S.-C.,Hakimelahi,G.H. TL37,2035 (1996). 'Erans, P.A., Longmire,J.M., Modi, D.P. TL36,3985 (1995). 'Erans, P.A., Nelson,J.D. JOC 61,76Cf,(1996). '\air, V . , M a t h e w ,J . J C S ( P l ) l 8 8 l ( 1 9 9 5 ) . \tagnus,P., Barth, L., Lacour,J., Coldham,I., Mugrage,B., Bauta,W.B. f 51, 11075(1995). '\rai. N., Narasaka,K. CZ 987 (1995). '\f ichizuki, T., Hayakawa, S., Narasaka,K. BCSJ 69, 231'7(1996). -Hsu, J.R.,Chen, K.-L., Ananthan,S., Patel,H.V. OM 15,499 (1996). ?:rrlobelli,A.B., Ruzziconi,R. JOC 61,6434 (1996). 'P:olobelli, A.B., Ceccherelli,P.,Pizzo,F., Ruzziconi,R. JOC ffi,4954 (1995). .'{uu. J.R..Chen,C.N., Shiao,S.-S.JOC 60,856 (1995). \rrr. V., Mathew, J., Radhakrishnan,K.V. JCS(PI) 1487 (1996). {obayashi, K., Mori, M., Uneda, T., Morikawa, O., Konishi, H. CL 451 (1996)' 'rrgiyama, T. AOMC9,399 (1995). \fandal, P.K., Roy, S.C. T 51,7823 (1995). 'l:mpoor, N., Kazemi, F. S 821 (1996). '-"no. C.S.,Tanabe,K., Itoh, O., Uemura,S. JOC 60,274 (1995).

7n

Cesiumlluoride

Cesium acetate. (with ClCHrSO,CVpy)'treaftnent I nver sion of at'cohols'l By chloromesylation is convertedinto its una iyOrotyris, a se"ondatyalcohol with CsoAc/18-crown-6, enantiomer. T' TL37'6145$996)' rShimizu, S''Nakata' T.,Hiranuma, -7

a-Carbanions of phosphine oxides are fq .\posure to CsF/18-crown-6.Their rerum .r-dipolar cycloaddition to form tecrahld -:adiIy generatedfrom cr-chloro-a'-rinrthl I

-7 5; 18' 87-88

13,70; 14"7'7 8; t5' 13 carbonate.--'C'rito), -""'ii'"iirillir".i Cesium orphenols' "::1li thealkvlation hasbeen

anenoneto Additionof a B-ketoestermoietyto Intramolecula,ui"iA oiAun''z efficient' is asthebase (e.g., a l4-memberedring) usingcs,(co). '1h" a macrocycre form '""";;;;;;;;;j tosvl azide to active diazo a of iroup"from intoduction room temperature(8 that the reactiontake place at methylenecompoundst"qoit"' of Cs'(CO)t' .*urnpt.., 9l-99Vo)in thepresence rlr", J.C.,Yuk'I.Y',Cho,S'H'SC25'1367(1995)' P' BSCF132'371(1995) t;;i.;;., G.'Deslongchamps' (1995)' 3t ". J.C., Yuk,J.Y'SC25'1511 Cesiumfluoride.13,68;14'19;t5'75-'16;16'69-70:17'68;18'88-89 Asbase.Theo-alkylationoftetronicacidsandthealkylationof2-pyridone(ato withprimaryhalidesanoatNwithsecondaryhalides)aremediatedbyCsF.llneachcase thedisplacementofsecondarymesylateswithcarboxylicacids2andmalonicesters3 proceedsstereoselectiveryu,ingCsFasthebase,therebypermittingthepreparationof ctriralsuffi;-dimethylchroman-4-one from o-hydroxyaryl systemcanbe constructed closure Michaelreaction.while thering l_prop.nvrx",ln". iy anintramolecular I _methyliscatalyzedbybothacidsundbu,..,thebestdiastereoselectivityisobtainedwithCsF'a

c*

\ synthetically significant application is tl .-:racteristic of dynemicin through Or rnt

r.:clrvdes.9 A preparation of Suzukicoupling.to :' ::rted by a coupling at the terminal carbcx

- o BuLi;

'

\

c /.-o / \o'B-':''

Cp2ZtClz; R

HCI

OMe CsF/ THF 6 0 0 , 1d

quant(transcis95:5) olefination employs a A new version of the Peterson Desilylative reactions' epoxide an aldehyde' and CsF's Similarly' combination of ethyl tnmemylsitytacetate' using by avoids strongly basic conditions synthesis from carbonyt "ompoonOt methylide'o erJ*Tfo- as a sourceof the sulfonium linriatrstn

..,: . T.. Yoshimatsu, K., Otera, J. Sl 843 t 1996 . . r T . . O t e r a ,J . S / , 3 3 6 ( 1 9 9 5 ) . '.u . T.. Otera,J.IOC ffi,2627 (1995\. -..',iawa. T., Oku, Y., Kotake, K.1., Ishii. H. ./( ;': ..r-:soued.M.. Ozanne,N' JOC 60' 6582 t l9{ '' , ir. K., Tani, S., Sato,Y. S 649 (195). 3nen. P., Warren, S. SL 579 (1996). "-, ,. M.. Ishibashi,N., Hosomi, A. S4 234 (19

Cesir.n fluoride

ne-:.rtrr)n (with ClCH2SOrCVpy)' treatment into its i. j ...ondary alcohol is converted

cx-Carbanionsof phosphine oxides are formed from the a-trimethylsilyl derivatives on exposure to CsF/18-crown-6. Their reaction with benzaldehyde is 4t?ti-selective.TIn a l,3-dipolar cycloaddition to form tetrahydrofuran derivatives, the carbonyl ylides are readily generatedfrom c-chloro-a'-trimethylsilyl ethers.8

.^l{rt.

!-:{

cl -5.

-:

a\

18.87-88

ux'-: :n the alkYlationof Phenols' \-r.r::r(\n of a p-keto estermoiety to an enoneto r.: .'r:.g Cs'(CO), as the baseis efficient' . i : JrrTo group from tosyl azide to active (8 i :r 1-::,\n take place at room temperature

U

ttressj

Y

CsF/ MecN

?'

o

enlo/ Ph (85 : 15)

-( (,-

I

75/.

J

I

-

^)5r.

A synthetically significant application is the CsF-inducedclosure ofthe enediynebridge ;haracteristic of dynemicin through the intramolecular addition of silylated alkynes to

-.

1 t ^ v - 7 0 :1 7 , 6 8 ; 1 8 , 8 8 - 8 9 (at O I - .- .:- and the alkylation of 2-pyridone case In each CsF't by ,,.rJe.)are mediated t:Jesters3 malonic E. . r:. ;arboxylic acids2 and -.1\i'. thereby permitting the preparationof i'.-. . -':-*.can be constructed from o-hydroxyaryl ts the ring closure Jrl . - .:r \lichael reaction' While CsF'a tv:. : :-tereoselectivityis obtainedwith

rldehydes.e A preparation of B-aryl enones from l,3-diborylbutadienes is Suzukicoupling.to :nitiated by a coupling at the terminal carbon. CsF is presentto facilitate the reaction.

){o

BuLi;

to-B\.

Cp2ztol2;

\

R

HCI

O R r l B-?',rZ'e

Phl

_

CsF - (PhP)4Pd

t

'

. 1 ,n,#a I

THF

o,_.o

-ft-

FI

A

o , _ .o

-/-t-

| ^-, o- , , r , ,

i

OMe

Cr :

'-=

^ . tn-Z

R 1 \r^n tl

o

95:5) quant'(transcis - ,,f the Peterson olefination employs a epoxide !?.:- .,:. rldehlde. and CsF'5 Similarly' using by conditions basic iuongly :i. b -. 'ntum '-.: methYlide'6 ln \i-.

.:ro. T., Yoshimatsu, K., Otera,J. St 843(1996). .:ro. T., Otera,J. Sf 336(1995). .:rtr.T., Otera,J. JOC 60,2627(1995). i.hrkawa,T., Oku,Y., Kotake,K.-I.,Ishii,H. JOC 61,984 (1996). N. ./OC60,6582(1995). M., Ozanne, 3ellassoued, 'ii:.rki. K., Tani,S.,Sato,Y. S 649(1995). , Bnen,P.,Wanen,S. SL 5'79(1996). ':i 'rt-r. N., Hosomi,A. 5L234(1996). M., Ishibashi,

Chiral auxiliaries and catalysts eWender, P.A., Beckham,S., Mohler, D.L.TL36,209 (1995). roDesurmont, G., Dalton, S., Giolando, D.M., Srebnik, M. JOC 61,"1943(1996).

A member of the new ligand c bis(dihydroquinidine) ether of l.-t{rl ligands bound to soluble polymer s

Chiral auxiliaries and catalysts. 18, 89-97 Due to the extensive literature, only a portion of thesereagentsis mentioned. The chief criterion is their efficiency (e.g., mostly > 90Vo ee),unless the utility or reaction is novel. the yprostereogenic enolates with Protonation of Protontransfer. hydroxyselenoxides, such as 1, sometimes gives excellent ee.r The SnClo complex of a

Jihydroxylation.

Selenoalkoxylationand -lactonizatro rnd 8r3, the ferrocenyl diselenide9r.. : trocesses.The diselenidesare actii.ated

methyl ether of chiral BINOL can be used in catalytic amounts to protonate silyl enol ethers, affording ketones in high optical yields.2A catalytic enantioselectivedeprotonation to form a bromoalkene3is achieved by KH in the presenceof N-methylephedrine. The Cr-symmetric phosphine2 is useful for enantioselectiveacylation of Acylation. alcohols.aChiral mixed carbonatesare preparedfrom3 and secondaryalcohols, allowing a

,.o-{ \7-N

kinetic resolution of the alcohols.5

\^Se

|}

-f

o"

\sd":

riY MeolV

*o

(1)

j I

I

t

!o

Lb . t .' to-{

'o

\\

I

c

(7)

,P_Ph

\

OMe

(2')

vl

(3) The conversion of meso-anhydridesto chiral monoisopropyl esterscan be performed by reactingwith diisopropoxytitaniumTADDOLates.5" Hydrotrichlorosilylation of l-alkenes, which provides Additiantodoublebonds. intermediates for chiral alcohols, is Pd catalyzed with a binaphthylphosphine (4) as

Heckreactions. The o-oxazohn :r;ellent ligand to direct enantiosele ::,'xazolinylmethanederivative12 hash ' -nctionalized aryl iodides.rT

ra\

l l -Y"Yo i

ligand.6'7 Hydroboration

complex of with catecholborane catalyzed by a (5)8 high enantiois accompaniedby l-(2-diphenylphosphino-l-naphthyl)isoquinoline (6) promotes alkylaluminatione selectivity. Bis(l-neomenthylindenyl)zirconium dichloride rhodium

PhsP

N\

of l-alkenes through a noncyclic mechanism. (11)

cq.

(> CF3SO3

@"n' R = oMe

(44)

R=H

(48)

(5)

.4,Aol reactions, The copper comp r .:l\ lketeneacetalswith (benzyloxl.trt \n approachto 5-hydroxy-3-ketoesrcr n , ,lr.esa titanium alkoxide derived from rn imino-BINOL complex 15 is effec (6)

Chiralauxiliariesandcatalvsts 73 A member of the new ligand class for the asymmetric dihydroxylation is the bis(dihydroquinidine) ether of 1,4-dihydroxy-9,10-anthraquinone.r0Cinchona alkaloid ligands bound to soluble polymer supportsrr are effective catalysts for asymmetric

I -'. .eq5). l.: . \1 IOC 61.7943(1996)'

cv:: :r ,'i thesereagentsis mentioned'The chief f,, r'.' ,. unlessthe utility or teaction is novel' .:.:r'reogenic enolates with the Y-

dihydroxylation. Selenoalkoxylation and -lactonization using chiral areneselenenylderivatives such as712 and 813,the ferrocenyl diselenide 9ra, and the camphor-basedspecies(10)15are efficient processes.The diselenidesare activated by Br, to form reactive selenenyl bromides.

!:.:- .\cellent ee.l The SnClocomplex of a r..:i-, r lrc amountsto protonate silyl enol ethers, "., cr'.-: . enantioselectivedeprotonationto form Ir.. ..,i \'-methylephedrine. - I - .r.eful for enantioselectiveacylation of t '- nr 3 and secondaryalcohols, allowing a t\''

,,o-

l

(41)

t-+-L9 L'SJ/ \:nong chiral ligands for the Simmons,i: r.rhrrolidine prepared from tartaric acid o::- ..1r'43.85A thorough survey of a seriesof

I 6^5 + . l -ph TfO

.

(48)

(47)

Glycine incorporatedinto Oppolzer's sultam is transformed into the Cyclaadtlitbns. with imines to form pJactams.ea that reacts ketene sulfamido A2

N02 NHSO2Me

\

') (43A)

lt13

F. ^ ':. -nd. r'ia decomposition is amenable to '- :i:. chelates. Rhodium complexes of * .::::.ulfonYl)proline 4487arc typical. The latter D\ ,..:-\'n\)ids. For intramolecularreactions,the

h,," J,A^,^ 'cooH ,' \-soz

o

--N

h )'

II PhoPcb - Et3N CH2C!2,-23o->2f

OMe

i-r'.JiJ6'u are effective.

rr

The participation of TADDOL-Ti(OTs), in the 1,3-dipolar cycloadditione5of nitrones to alkenesensureshigh diastereo-and enantioselectivity. The novel chiral Lewis acid (49) is an excellent catalystfor Diels-Alder reactions.%The rrans-4,5-diaryl-1,3-bistriflyl-1,3,2-diazaluminolidines (50A) have been exploited in the elaboration of a chiral tetrahydrophthalimide intermediate for the synthesis of gracillin-B

: -, ,,,: ':-r.l€-

and gracillin-C.e7 A dioxaborepin 51 prepared from a substituted BINOL and 3,5-bis(trifluoromethyl)benzeneboronic acid is a Lewis acid catalyst for enantioselective Diels-Alder

t-\ttl :

reactions.e8

45 (46)

U

Chiral auxiliaries and catalysts

Ar.

Other catalysts are a ketodiolide 54t": ", :poxidation with the latter catalyst using nas .::te is favored.

.Ar

/

\

N)t' N.so2R RSO2X

(4e)

p = cFa (50A) R = 3,s-(FsC)zCoHs(508)

( cfu-

OQIh"(51)

(s4)

Pauson-Khand reaction, The intramolecular annulation of enynes promoted by a chiral titanocenederivative 52 exhibits high degreesofenantioselectivity.ee

For epoxidation of enones and relared s :.'llleucine exerts desirableeffects, yieldrq i-aone epoxidation with oxygen in I :< $ y lpseudoephedrineI07is also satisfacron

€

o"7)'RCFs.l AlcoholsreactwithCK .:rh KF and CuI in DMF at l00o under N". und

Coupling of allcynes with organoiodides. :-c reactionof l-alkynes with iodoalkynes leadsr

CopperQ) iodide

r

rY)

1 9 9 6) .

t ),

1$5). . Renaud. J., Untersteller, E. ACIEE 35' 889

rrc

VYt-o\,,,ph Br, Br

l - B u L/ T i HF,-7d; ...........'........................................._

I

C U C N ;O z

r t , 1 1 h

92% (mainproduct) a-Acetox! ethers.z A general procedure for the preparation of these compounds is accomplishedby DIBAL-H reduction of esters(lactones)and subsequentacetylation. Amines from amides.3 This reduction method is suitable for cr,o-diamides. A stereoselectiveapproach to cycloheptenols is based on the Hydroalumination.a cleavage of 8-oxabicyclo[3.2.1]oct-6-enes.The lack of generality for the fragmentation protocol plagued the method. Now a useful procedure consists of Ni(cod)r-catalyzed hydroalumination and treatment of the alane with r-BurAlCl. This method is also appropriatefor the asymmetric synthesisof cyclohexenols'

generates -:r,'1ateswith Zn(Ctlfr-BnOLi '^ complete aldehydes, then ;-PrO)TiCl.,and 1 .,

Ni(cod)2 - (A-BINAP

1

iBu2AlH

D 54% (80"/" ee)

..

o

_

+

.

-

B

n

,\I

rv*

BocNHf

.

o

on iln#H i \

H

(,Pro)ricb

r

O

Ll \/

'

Bn

BocNH CHO

ftr

'Oika*u,M., Oikawa,H., Ichihara, A. I5l' 623'7(1995)rDahanukar, S.D'JOC 61,8317(1996). V.H.,Rychnovsky, rcibo."uu.P.,Morin,C.,Vidal,M. SC26' 515(1996). {Lautens,M., Chiu,P., Ma, S.,Rovis,T. JACSll7 ' 532(1995).

\2 59% (>99% d6)

Diisobutyl(phenylselenyl)aluminum. I Regioselectivehydroselenationof l-alkynes affords a-Substitutedvinyl selenides. an accessto the selenides.

::r. \1.. Volante, R.P., Reider, P'J' JACS 11E' iBu2AlSePh

Ph.

\

hexane - PhMe L

f5 DI: !i{

r--l-l8r 16,134-135;17,123-125; .'ffects a reductlve nng opening of

Ph'PhS/-

24h

85%

rDabdoub, A.C.F.TL37,9005(1996). T.M.,Batista, M.J.,Cassol,

f30

Dirnanganesedecacarbonyl

borohydride. 18, 142 Diisopropoxytitanium(Il! Reductions. Aldehydes, ketones,acid chlorides, carboxylic acids,and N-Boc amino acids arereducedto the correspondingalcohols,generally in excellent yields.l The reduction of cx,B-epoxyketones gives alcohols without affecting the heterocycle.2 rRavikumar,K.S.,Chandrasekaran, S. JOC 61,826(1996). 2Ravikumar. S. T 52,9137(1996). K.S.,Chandrasekaran,

l{- Dimethoxybenzoylformic acirl The be Oxidation of alcohols.t ' rive carbonyl compounds (4 exampl

R.J.JOCffi.2$l r L:rung,M.C.,Tepper, lJ -Dimethoxy-5,5-dimethyl-43- I J.l 3,3-Dime thoxy hydroindolo n cs.'

The cothermol)sis ::nethoxycarbene.2 -r droindolonesvia a [l+4]cycloaddio ' ritled by tazettine is conceivable.

Dilithium tetrachloropalladate. Annulation with vinylcyclopropanes and -cyclobutanes.r

EIOOC. .COOEt

(1.cH(cooer), +

2",_

\-/-'

Li2Pdct4

V

"-;

/-'r4

!,|J--/-\_

8oo,3 d

of dienes'' Chlorocarbocyclization cyclization. Pd(II)-catalyzed

82/"

Dienes tethered to an allylsilane unit undergo

Rrgby,J.H., Cavezza,A., Ahmed. G. ./.{C ''',ruture. P.. Terlouw, J.K., Warkentin.J J

Meoocr -cooMe ffft

\2

(

(:r. fooc;.coorvr" ''Y>.'\

b"-"il""*HOAo- acetone

-f I ) =--L

"'..,"":tkcooMe

Li2Pdct4-Licl

7r: ( 3 : 1 )

) SiMe2Ph

68'/"

'Larock.R.C..Yum,E.K. T 52,2743(1996). 2Castano. A.M., Biickvall,J.-8."/ACS117,560(1995).

Dimanganesedecacarbonyl. The successiveaddition of two different organolithium Unsymmetritalketones.t reagentsto Mnr(CO),6 leads to an unsymmetrical ketone. An unsymmetrical cr-diketoneis produced when the reaction is carried out in the presenceof trimethyl phosphite and is quenchedwith NBS. lYa.u.oto. H.M., Sakurai,H., Narasaka, K. ECSJ69, 157(1996).

lJ -Dimethoxy-3-methyl-3-butano Claisenrearrangement.t Heao : a mild acid gives a rearrangedk ..&unsaturated acid.

*

. f r \,(

22-Dinethoxy-3-methyl-3-butanol

It :: t . :.. :rdes.carboxylic acids, and N-Boc amino I ri.. : : rerallf in excellentyields. The reduction I :ii:- ttn! rhe heterocYcle.2

t

il

.i*

2,4-Dimethoxybenzoylformic acid. The benzoylformate estersare photolabile and decompose Oxidation of alcohols.t to give carbonyl compounds (4 examples' 65-88Vo)' 'Pimrng,M.C.,Tepper,R.J.JOC 60' 2461(1995).

2,2.Dimethoxy-5,5-dimethyl-A3'1,3,4-oxadiazoline. The heterocycle 1 is a convenient precursor of 3,3_Dimethory hydroindolones.t I and vinyl isocyanatesleads to the formation of of The cothermolysis dimethoxycarbene.2 alkaloids hydroindolones via a [1+4]cycloaddition. The development of an approach to tvoified bv tazettine is conceivable.

-ctclobutttnes,l

EIOOC. .COOEI

.

\l-l-\_

J U

D:-:-

o1 .\\

Z>.\

- ; lClr

- N X

a20/o

orHP

THPO

rfl-(o-oMe

OMe

o N

y"6'

tetheredto an allylsilane unit undergo

/ ou"

A

CH(OMe)2

(1)

'Rigby,J.H.,Cavezza, A., Ahmed,G. JACS118' 12848(1996)' :Coutu.",P.,Terlouw,J.K.,Warkentin,I. JACSlL8, 4214(1996)' t,t::.1,:

COOMe

Cl

+

( 3 : 1 ) 68'/"

2,2-Dimethoxy-3-methyl-3-butanol. Heating an allylic alcohol with this reagentin the presence Claisen rearrangement.t ketol that can be cleaved by NaIOo to deliver the gives a rearranged ,rf a mild acid 'r.6-unsaturatedacid.

\^^+ OH

:r-. : rJdrtion of two different organolithium lFr: ..:. ierone. An unsynrmetricala-diketoneis ! .- :. Fresenceof trimethyl phosphiteand is

+'

. ,oH )( ,oMe

fou.

2,4-(OzN)zCoH:-OH t3oo, 5 h

M - cooH

X . ^e ^*-\ Et2O t

^r\-o)'9t" ...( ,.... Bno-o{" I I Bno"Y'oen 6en eno""t'oH OBn 92'/"

l{' Dimethylsulfoxonium methv-lide' Under"stl CyclaProPanation'' '--.. y lide adds to enonesefftcientlr r from th The Ylide can be generated 100''at MerSOo l\lSO and V.M', Carlson'R'M SC! .:x.stakovsky, \ ..'.rrester, J.,Jones,R'V'H" Preston'P

fXmethYltitanocene' 2-MethYleneoxetones'' ]- hctones with CPrTiMet'

Thcs'

JOC6l' -\.llinger,L'M , Howell'A'R

'

kldi lf-Dimethyt-1,2,4'triazolium Thc Benzoincondensation" condu is reaction The -.,ndensation' :. tte Presenceof the salt'

rstork,G., La clair, J.J.JACSll8'24'7 (1996)'

! rlrr ashita,A', Suzuki'Y'' Koba;"ashr

bromide' Dimethyl sulfoxide-hydrogen (9 examples' site-specificbromination suustlitutedbenzenesundergo Bromination., 36-9lvo)' 7,2-Diketones.'

contrastswith +^L^--lc by hv DMSO-HBr DMSO-HBr cor The oxidation of stilbenesto benzils

theresultsofDMSo-lroxidation,whichpreferentiallyconvertsatolanemoietyto cr-diketonein the same molecule'

12- DMSO

(

r-l

b-8.

I

Ph-1\

H1

)----Pn \,_-_7

Il Br2- DMSo>

' -E v 7-$ $,Z-DioxaborinanYt )atr'r1 Tl ond.t-lt*ene-3,4-dials't al bromide ::.rm allenylmagnesium t This -.3gent (1) by hydroboration' workuP :rtrducts that, on oxidative

Ph

'S.inurtuuu'S.K.,Chauhan'P'M'S ' Bhaduri' AP' CC26'7-9',1996)' s 1234(1995)' zyusubov,M.S.,Filimonov,v.o- v"rily""a' V P', Chi' K'-w'

P

BrMg.

I@)- Z-(13,2-Dioxaborinanyl)allylldiisopinocampheylborane

=^1.o"\'lo"io - ^ \-o--."'soPh

...OMe

""oBn

OBn

Dimethylsulfoxonium methylide. 14' 152; 15, 147; 16' 146; 17, 126-127|.18' 148 "superbasic" conditions Under [KOH, (BnNEt,)*C1-, DMSO], Cyclopropanation.r (7 86-94Vo). examples, efficiently to enones the ytide adds which is obtained from The ylide can be generatedfrom the salt (MerS:O;*(MeSO/-, at 100'.2 DMSO and MerSOo rshostakovsky, R.M. SC26, 1785(1996)' V.M., Carlson, rFooest".,J.,Jones,R.V.H.,Preston,P'N.,Simpson,E.S.C."/CS(P1)2289(1995)'

rt2o I

cHzcr, | /*\' Et2O +

rDimethyltitanocene. 2-Methyleneoxetanes.t Theserare compoundsare now availableby reactionof p-lactones with CprTiMet.

^'\-o\"'o""

t"o^foYl"o'.V"or" ano"t'oH

6an

OBn

'Dollinger, L.M., Howell, A.R. "/OC 61, 7248 (1996).

2,4-Dimethyl- \p,4-tnazolium iodide. Th" azolium salts are effective catalysts for benzoin Benzoin condensation.l by heating an aromatic aldehyde with NaH in THF is conducted condensation.The reaction in the presenceof the salt. rMiyashita,A., Suzuki,Y., Kobayashi, M., Kuriyama,N.' Higashino,T' H 43' 509(1996)

(9 examples, > .. :::i{, site-specificbromination D.-r" -. r,' benzilsby DMSO-HBr contrastswith --':rrentially converts a tolane moiety to i-

l( E) - y-(1,i,2-Dioxaborinanyl)allylldiisopinocampheylborane' The ready availability of B-allenyl-( 1,3,2-dioxaborinane) anti-1-Alkene-3,4-diots.t from allenylmagnesium bromide and the borinyl bromide makes it possible to prepare the reagent(1) by hydroboration. This reagentreactswith aldehydesstereoselectively.yielding products that, on oxidative workup, are transformed into the alkenediols with gcnd de and

!

,n-\

oyrn 71 -\_1/-\

(^p I

BrMs.

I +

;-B cl

-u-

Et2O

(

P

(lpc)zBH

b-8. \

b-8. - 7Bo

/

lpc2B (1) RcHo I - 78o;

{

NaOOH

OH

t

\ i

\

:h-q tl996).

(1995). K -\r'.s 1234

(de >95%) (ee90 - >95%)

*'Y\ 6H

^

140

Diphenyldiselenide

tBro*n,

H.C.,Narla,G. JOC 60,4686(1995).

Bz-Leu

Diphenyl chlorophosphate. Glycosyl chlorides.' Sugars containing acidJabile groups can be converted into glycosyl chlorides by reaction of the corresponding lithium alkoxides with CIPO(OPhl.

.,,\a"\""oH " \ / H',,,n,,,H

N3CH

\ . L., Stuhr-Hansen. i{enriksen. A., Fujii.H . the. H., Yamasaki, M. CC{75 , l{rn. L.-B.,Tanaka, '.ihosh. S.K.,Verma,R., GhoshI

Diphenylsilyl dichloride. I ntramole cular Dic ls - A l ,,\ntrol the Diels-Alder rea - r-adrenosterone.rThe first ':r'atrrr€ntof an alcohol beann

crPo(oPhD

o- ,u

+

THF 0o-> rt. 15 h

lHung, S.-C.,Wong,C.-H.TL 37, 4903(1996). Diphenyl diselenide. 13, 125; 18, 15 1- 152 Very pure PhSeSePhcan be prepared via dihydroxy(phenyl)selenoniumtosylate [PhSe(OH)r]*OTs-by^treatmentwith33Vo HrO, and TsOH.r Benzgl selcnides." PhSeNa derived from PhSeSePhand NaBHo converts benzyl alcohol to BnSePhin the presenceof AlCl.. The direct transformation of benzaldehydesinto the selenidesis achievedby this system. (In situ reduction of ArCHO initiates the process.)

o.-:r, I

t \

a-t-\

't-1=-zV ,/s

ftHydroxy selenides.3 In combination with nitrogen dioxide, PhSeSePhreacts with alkenesto afford p-nitratoselenides,which, on contactwith silica gel, arehydrolyzedto the correspondingalcohols.

c o Hsr .

c6H13

coHrs

phseseph

\

-

-aoo. 0.5 h -t rt, 12 h

foNo2

\""rn

:g1

ro* -s"Ph

(+)-adrenosteron 69% (overall yield)

C.D.,Zandi,K.S..\lt ll ,'zrerba, Peptide synthesis.' Peptide-bondformation from N-protected amino acids is readily achieved by reaction with cr-azidoalkanoicesters,which is promoted by PhSeSePh-BqP in a mixture of DMF and MeCN at room temperature.This is a rapid and self-regulated process.

Diphenyltitanocene. Aldol condensation.l : heating the reaction partn
1 0 0: 1 )

Ir -.-:1996).

--;C2.

1 equiv.

ll- rrillt1995)

.":hers'Highpressurefurtherfavorsthereaction.IExclusiveendo-selectivityinthereactions - alken-2-oneshas been determined'2 - r crlving (E) - l -benzenesulfonyl-3 Allylic methoxyacetates undergo reTransposilionof ailylicm-ethoxyacetates.3 with Eu(fod)t' Synfact:t^ttt:.t^::t the ester :jrrngement at room temperatureon treatment .loupisobserved.TherearrangementiSefficientandnotsubjecttosterichindrance, 'eJause the metal coordinateswith the tether atoms'

.:brritution at the CHr group of PhrC:N-

'. R . Roglans, A. TL34,8535(1993)'

r.:---ri r. availablein two stepsfrom the reactioo " ; - - . rn 607c yield. It shows a stereoselectivity I .:"t l(racetateesters.

\-. Er

rc'. undergo trifluoroacetylation only at the I acetonitrile. Very highly selective .- Jc.or.rs -,.'cn achieved2using one equivalent of thc

H'W' ?51' 8383(1995) D.A.L.,Scheeren, \ rndenput, S'-?52' 1205(1996)' '.r Chin'U'' Kanemasa' H', Yasuoka, W., Pei, 8., rda, (1996)' I1690 118' M '/ACS :rull. B.K.,Sakai,T.' Koreeda'

OH atN:

I

N F

(l

F l u o r i n e . 1 31,3 5 ;1 4 , 1 6 7 ; 1 51,6 0 ; 1 81' 6 1 the introduction of bromine or Electrophilit hnlogenation'' Fluorine facilitates iodineatomsinto aromaticnuclei' F\ F\

F1

Fz-tz

/-\

//

F-\

H2so4

Y

F

Sravber,S., Zupan,M. TL37,3591 (lc)96l' riravber, S., Zupan' M., Poss,A'J , Shia' G.A fL

/'

/F

Fluorofunctiona[imtion of alkene s': \teOH), an additionreactionto alkenesa'cr

/f-'

rAr 667"

of sulfides (e'g'' thioglycosides)and Fluorodesulfuriution.z The C-S bonds with Fr-It' arereadilyreplacedby theC-F bondon reaction dithioacetals

-(L \-Ftuoropyridinium sulfonates'16' l Fluorination.L lnternalsaltssucha-r 24-517o),anisole(83ctr' thr I examples, :nol ethers(4 examples,88-937c)'andF l

'Chumbe.r,R.D., Skinner,C J', Atherton' M'J'' Moilliet' J'S' JCS(P1) 1659 (1996)' (1996)' 'Chumbe.r, R.D., Sandford,G', Spanowhawk'M'C'' Atherton' M'J' JCS(PI) 1941 r3u

Fluoroboric acid. 18' 162 Diels-Alder reactions.r

an acetal group Enones substituted u, ,5" 6x'-positionwith

formcyclicvinyloxocarbeniumions.Theenhanceddienophilicreactivityofsuchspeciesis syntheticallyuseful,anddiasteroselectiveprocesseshavebeendevelopedinwhichthe ionizationismediatedbyfluoroboricacid.Scandium(Il!triflateprovideslower diastereoselectivity,andBF,..oEt,isuseless,asextensivedecompositionofthesubstrates occurs.

'.r ,I( -o- ,oEt v/ )r -r I I ,/ \

t

HBF4 cH'ct' _45"

tql

H t l a'^'-l-\rot

isoprene; ;;

.\)

lq memoto,T', Tomizawa' G' JOC ffi' 656-:

\ -Fluoro-1,2,3-oxathiazin-4'one' Fluorides.t This stable' crlstallrt . r eetenerAcesulfam.It fluorinatesenttla andanisoles' :rol acetates

,\

(1995)' summukiu,T., Berliner'M'A JOC 6O'6652

'2'2loctane bis(tetrafluoroborate)' 1-Fluoro-4-hydroxy-1,3'diazoniabicyclo[2 with reagent (1) often proceeds fluorination Direct Fluorinationof ketones.r high yields, providing cl-fluoro ketones' 146

'

\

' rbrera,I., Appel,W.K. ?51, 10205{ l9q5

N-Fluoro-1,2,3-oxathiazin-4-one 147

OH I

.i\ t \ l

--(a

2 BF4

F

(1) the introduction of bromine or

'J '1 -

F

/f-l

F

l

66% ' .ulfides (e.g., thioglycosides) and d

of a nucleophile (e'g'' Fluorofunctionalizntianof alkenes.z In the presence rteOH),an additionreactionto alkenesoccurs(12 examples'90-98Vo)' Stavber,S., Zupan,M. TL37'3591 (1996)' :Stavber,S., Zupan,M.' Poss,A'J., Shia, G'ATL36,6'169 (1995)'

\ -Fluoropyridinium sulfonates.16, l'10-17l; 18' 162 agentsfor styrenes Ftuoination.r Internalsaltssuchas(1) areexcellentfluorinating lexamples,24-5|vo),anisole(837o)'thioanisole(807o),Z,3-dihydrofuran(757o)'silyl (5 examples'46-98Va)' :nol ethers(4 examples,88-937o),andB-dicarbonylcompounds

:r.rctionwith Fr-Ir. 'r'\rPlt

r'.'-

1 6 5 9( 1 9 9 6 ) . \l J JCS(P.I) 1941(1996).

CFa

A ll.l r.c^t't'

':1. G'-positionwith an acetalgroup :\, :' rr: .: :::, 'philic reactivityof suchspeciesis r.-. :.,\e been developedin which thc :-.,':.irum(lll) triflate provides lowet !r.'- -:r e decompositionof the substratc

soi

F

(1) '.

G. JOC 60,6563(1995)' T., Tomizawa, memoto,

\'- -Fluoro- 112,3-oxathiazin-4-one. artificial This stable, crystalline reagent (l) is derived from the ituorarr.t as esters, well as .\\.eetenerAcesulfam. It fluorinates enolatesof B-ketoestersand malonic $prene;

inol acetatesand anisoles.

r,leOH

Z#N'F I

lt

\./i^-su-"

lortanc bis(tetrafluoroborate). rr: .,rrh reagent(L) often proceedsin

(1) 'Cubr"ru,L, Appel,W.K. ?51, 10205(1995)'

\-,o b

148

Formic acid

Fluorotrichloromethane. of the Barton esters in Chlorodecarborylation-t Photochemicaldecomposition FCCI.leadsto chlorocomPounds'

((bbFq FqP

OMe

\

rn

cFcl3

MeOOC-..r, -N^-S

hv

Meooo--", H",

\u o lDrllu, E.w., Taylor,D.K. IOC 59,2986(1994)'

Formaldehyde dimethylhydrazone' The reagent adds to nitroalkenes, gtvmg Hydroformylation antl hydrocyanation.r by ozonolysis and into nitro nitriles by adducts that are transformed into nitro aldehydes teatment with a Peracid.

OAc

cH2cl2

ozN

rt, 6h

rLassaletta,J.-M., Femandez, R., Gasch, C', Vazquez' I' T 52'9143 (1996)'

Formicacid.13, 137;18, 163 a l,2-bismethylenecyclohexane Reiluctivecyclimtionof tliynes.t The formationof The to drimanesesquiterpenes' approach an for unit from the l,7-diyne is the key feature EtrSiH' andHCOOH in tolueneat cyclizationconditionsusing ldba;red2'CHcl3'PhrAs' thePd(0) g0oseemto be oprimal.no.mic ucidi, c.iti"al to help shift the equilibriumfrom species' catalystto theactivehydridopalladium

rc@( d

xt. B.M., Fleitz, F'J', Wa&ins

\t''

l

Formic acid

.:rron of the Barton esters rn (dba)sPdzCHCla FqP - Et3SiH HCOOH/ PhME 8d

Meooc-', '4ct

:.'nt adds to nitroalkenes' givtng 'r,,lrsis and into nitro nitriles by

-.

/:

3:N

t -

(r

rrrl996).

i .r 1.2-bismethylenecyclohexanc Thc f .:-:-.(rr drimane sesquiterpenes. a toluene in HCOOH and \. i' \iH. Pd(01 the from . ::t the equilibrium lr ).'

79"/"

(1996)' Trost,B.M.,Fleitz,F.J',Watkins,W'J.JACS118'5146

Alexakis, A., Tranchier, J.-P., Lensen, N.. Maneet

Grignard reagents.13, 138-140;14, l7l-l' As bases. The formation of phosptr l.l-dibromoalkenes to acetylenef are r\ro Gallium-lead0D chloride. Reformatsky-type reagents.t The synthesis of B-hydroxy nitriles (9 examples, 55-99Eo) and p-hydroxy o,cx-dichloroalkanoic esters (9 examples, 60-g0zo) from iodoacetonitrile and trichloroacetic esters, respectively, is mediated by Ga-pbcl,

in

refluxing THF. tZhang,X.-L.,Han, Y., Tao,W.-T.,Huang,y.-2. JCS(pl) 189(1995).

EtMgBr) as a base. Ketone syntheses. Acyl derivatives du reyond the first round include A:r) 1 'rrbutylphosphonium chlorides (generaredrn :nvolving N-methoxy-N-methyl carboxamdr c-chloro ketones,6cr-ketoamides,and q,{rtcr Svmmetrical diketones are obtained br rh rethiodides.8 Note that an analosous reruq :urnishesaldehydes.e

Gallium0lD iodide. Propargylic alcohols.t

Condensation of alkynes with carbonyl compounds is simply accomplished by treatment with GaIr-Bu,N in THF at room temperature (16 examples,49-88Vo). rHan, Y., Huang,Y.-2.TL36,7277(1995).

Y". 'l N-(

R

\ o

R'Mg& Et2O

Glyoxal.18, 166 t Monoaminals. Th" chiral monoaminals of glyoxal are valuable building blocks as asymmetric reactions on them become possible. Thus, chiral aldehydes containing an q-acetoxy or o,-amino group are readily obtained from organometallic reactions directly or after condensationwith tritylamine. The addition of organocuprateto the unsaturatedester derived from an Emmons-wadsworth reaction generateschiral B-formyl esters.

'Yoyo, o

R

I--."'tn oHc-( | ,N^Pr' R

I

,"^tn R

h-cHo BocNH

R

R OHC-CHO *

HsPO.

,,N),,'tn

t-1 Ph3CN'

R'\

I

,f.f--.,..,en

I

AcO

,*^tn

v

R'MgBr

cHzcl2.-d

The reaction of 3-(1,1,3,3-tetranr0ll .romide (1) with aromatic nitriles gives I -rclodehydration of the releasedamino kerorr

)-cHo

AcO

h

---1*)"'tn * EoocJ/ )"{rn R

,,

\

R

,MSAr

.'Si R',

"'rcHo

ETOOCJ

|

+ PhCN

,N-

)s\ (1)

Grignard reagents

\lexakis, A., Tranchier, J.-P., Lensen, N., Mangeney, P. JACS Il7 ' 1076'7(1995).

-17 | Grignard reagents.13, 138-140;14, 17l-172:16, 172-173;17, l4l-142;18,167 As bases. The formation of phosphonium ylidesr and the transformation of l.l-dibromoalkenes to acetylenes2are two types of applications of Grignard reagents

: .)-hrdroxy nitriles (9 examples, e.':-. i9 examples,60-807o) from lr:: . r: mediated by Ga-PbCl, in

, EtMgBr) as a base. Ketone syntheses, Acyl derivatives that favor the arrestmentof Grignard reactions beyond the first round include N-acylpyrazoles.l acyl hemiacetals.a and acyl tributylphosphonium chlorides (generatedin situ from RCOCI and BurP).s The protocol involving N-methoxy-N-methyl calboxamides has been extended to the preparation of o-chloro ketones,6cr-ketoamides,and cr-diketones(the last two from the oxalyl diamides.)'7 Symmetrical diketones are obtained by the Grignard reaction of bis(benzimidazole) methiodides.8Note that an analogous reaction of 1,3-disubstitutedbenzimidazolium salts

. ^ 1 5) .

fumishes aldehydes.e

t,

s ith carbonyl compounds is THF at room temperature (16

Y': I

B . '.,. .rrevaluablebuilding blocks as T - . -hrral aldehydescontaining an )a' r l_

- :.rnometallicreactionsdirectly or :::,rupfnte to the unsaturatedester . .hiral p-formyl esters.

R

\\ o

Er2O

\ ,|t\r\

/

Z'-rN^ .-J / N-\v l

\

n

"Yoyo) v

R'MgBr cH'2ct2, -2Co;

cHo

BocNH

: Ph

'\-cxo

\pn

R'MgBr

o R\ ' / J \ R' //_

o

-

H3POa

)

o

2 l

.Ph

.' \H- .

n

R'98% ee)

i

m l

-

a

conjugate add.itions. 1-chloro-G,B-unsaturated sulfoxides give cyclopropane derivatives on Grignard reactions.rs Apparently, intramolecular displacement of the 1-chloro substituentin the cx,-sulfinylanion intermediatesis highly favorable.

Fr

n

(FrO)eB

Triarylbismuthanes bearing three differtl Grignardreactionsof arylbismuthtriflates. O..

o /--,aS-rot

l l l ^ ,

\,'^'. -

MgBr

;;

-.,..-..rS-Tol

t---,-2r\>

..\/^o

ll

O--\ | )rHn

Ar-&

A13Bi Ar'MgBr/ THF

Substilution ofal$loxy d.erivatives. 2-Alkenyl-1,3-dioxolan-4-ones undergo ring opening with Grignard reagents,with the attack controlled by the substitution pattern at C-5. The products can readily be converted to chiral allylic alcohols and protected o-hydroxy aldehydes(ozonolysis).r6

. |

N

Me3SiOTf-HMPA

These rea Vinylmagnesium bromidesur reaction Their reactions. rn Diels-Alder -rncd I 2-cyclohexeneto leads heatingat 130' retherto render the reaction intramolecular. so "coaxed" to partake in crclo Jienophiles are become reactive. Unlike silicon atom tetltec * orkup.

BuMgBr

Bu COOH

.r2u, -78o. 2 h

o P h

:

l

75"/" BuLi ;

The ring opening of endoperoxidesby Grignard reagentsand related organometallicsis I7 interesting, as monoethersof cis-2-cycloalkene-I ,4-diols are formed.

/\'

,

MgBt

Ir

Grignard reagents

::r,cr are transforrned into enamino t, I c.' .:r. imion.To retainthe nitrogenatom,

OH

ri\q \ro

\ 1- .\ lates undergo cleavage on reaction c - .: alcohols.r2while the cleavageof .: . rJc'salkenyl Grignardreagents,in the -r .::rr':ulfinyl)methylphosphonaterathe

-

Tol'

^*n,

xyrene

A l

4"1

.78O

THF,

t

/

+

^

83"/"

2'3-butadienylboronates' Reqctionwith boronatesand arylbismuthtriflales' Dab/l anionequivalents,areformedfrom allenylmagnesium *hich serveas 1,3-butadiene-2-yl r8 hromidewith dialkyl (halomethyl)boronates.

n v . t l

-

r53

, s .v , P h

tl

75% (>98"/" ee\

c

RCHO

)l I

l.-: . -.i sultbxides give cyclopropane 0: , ::rtramoleculardisplacementof the r: - : .:tr'\ is highly favorable.

z',uR

PhMe

n

(FrO)eB

I

o

H

59 - 950/0

Triarylbismuthanes bearing three different aryl groups are available by succesive re Grignard reactions of arylbismuth triflates.

o\ r

t

F

-

^

N

+

..'s-Tol Me.SiOTJ-HMPA

t-

V'rA

A13Bi

Ar

Ar-Bi

Ar-Bi

Ar'MgBr/ THF

Aa'

Me.SiOTt-HMPA

AT

Ar"MgBr/ THF

A/

u%

c.-. d ,

70 - 80"k

l.-l-dioxolan-4-onesundergo ring i.'d b1 the substitutionpattem at C-5. - elcohols and protected a,-hydroxy

These reagentscan be employed as alkene equivalents Vinylmngnesiumbromides. with lithium alka-2,4-dienolates followed by reaction rn Diels-Alder reactions. Their The Mg atom servesas a temporary reating at 130'leads to 2-cyclohexene-l-methanols.20 highly substitutedunactivateddienesand so that :etherto renderthe reaction intramolecular, "coaxed" to partake in cycloaddition. Even 4,4-disubstituted alkadienols Jienophiles are r€come reactive. Unlike silicon atom tethers, the cycloadducts undergo protonolysis on ,*'orkup.

Bu COOH

. , i/ \ , /l \

Ph

75%

5d""7;* L BuLi; I

rir'nl\ and relatedorganometallicsis .. are formed.lT

a

Xa)" [""

; w

154

salts Grignardreagentdcopper

Orall l a-Diketones and a-ketoesten' of -::nard reagentsin the presence CuBr r -:glrt)rt of the monochloride/esten of oralr'- e '1- and 5-oro \ convenient approach to (succinic and cl -:alrr)ns of cyclic anhydrides r aziridtrr: As Reactinn of aziridines' rea-oo 1r,.. phoamides) undergo electrophilic -::nard reaction and subsequentremor al of t

lshen.Y., Yao,J. JCR(R)394(1995)' 2Jiang,B., Ma, P. SC25' 3641(1995)' 'f"rfri.", C., Kita, I., Takahashi, K ' Hosorni'A' JHC 32'25 (1995)' 4Mattson,M.N., Rapoport'H' JoC 61'6071(1996)' tfnlu.ou,H., Okamoio, J.,ohmori'H'TL37' 5381(1996)'tTllly"t; R., rr"y, L.F., Tschaen, D'M'' Dolling' U'-H SL225(1996)' tiiii rta.p.,Marvin,M., Sharma, R' Joc 60' 5016(199s)' 8stri,2., Gu,H., Xu, L.-L. sc 26,3175(1996)' eshi,2., Gu, H. sc 26, 4l'750996)' tdli"p-[nt' M., De Kimpe,N" Fonck'G' sC 26' 3097(1996)' t tti6r, rra.e.,Marvin,M., Sharma,R' Joc 59' 4040(1994)(1995)' ttc"r.v, 1.,Ranaivosata, J.-L.,Bellosta'V'' Wietzke'R: s9 25' 3109 t'J"i.t,, f., Takano,K', Someya,H'' Matsuda'K'TL36"7091 (1995)' P'TL37' 6017(1996)' raCardellicchiu, C.,Iacuone'A" Naso'F'' Tortorella' (1995)' t'Tuk"moto,Y., Ohra'r', sugiiutu' K'' Imanishi'T'' Iwata'C' CPB 43'571 (1996)' l42l 37' IL r6Heckmann, B', Mioskowski]L', Sttun'R'K'' Falck'J R' rTSchwaebe, M.K., Little, R'D' TL 37,6635 (1996)' r8iounO*u*jun,R.' Li, G', Brown'H'C' JOC 6l' 100(1996)' t'frlutuno,v., Miyamatsu'T', Suzuki'H' OM 6l' 8 (1996) 2ostork. G.,Chan,T.Y. JACStl7 ' 6595(1995)'

of MO-bis(diphenylphosphinll thl dror 6 -, :.'reactive leaving group is present The Khara*h t Conjugate adtlitions' < .:::r stshasbeenevaluated'7Another reptxt' . ::e conjugate allYlation' The replacementof a p-methylthio re:rdtr l0 ',. :tro- &Irdstereoselective'9' Stz' displacements. A method fcr tr -.:nard reactionof FzC:C(OEI)CH'O'{c arn 'rn

-

18' I 7 I Grignard reagents/cerium(Ill) chloride' Dryingisimportantfo,i*p.ouingtheefficiencyoftheadditionreactions.rSuch reactions can be rendered catalytic' branching The synthesis from esters by a two-step 2-Substinted aUytX oioii"N., attack of an (alkoxysilyl)methylmagnesium homologation process involves nucleophilic chloride (2 equiv.) and oxidative desilylation'

MeooC. rl-oBn Y

:

v o,o).'U*n", Fro '

)ri

cect3/ THF -7Bo -> rt

.oBn

,rtro'Si-\ : g9%

KF -: ntW,

I r\^oec ' I

+ PhltgF

oEt

ethyl ethen't: Cad 1,2-Diarylethenyl -Br. andLiBr followedby Pd-catarlzed'-o ,examples, 58-84Vo).

-"/Y^o"n Ho ,Jl : 98%

tDi.itou, V., Kostova, K ' Genov' M' TL 37' 6'78'7(1996)' 'Mi"k"lron, T.J., Koviach, J'L', Forsyth' C'J' JOC 6l'961'7 (1996)'

171-173 Grignard reagents/coppersalts' 18' then are treated with N-tosylimidazole and l,2-diols When alcohols.| Homoallylic vinylmagnesiumbromideinthepresenceofCul,homoallylicalcoholsareobtained.This one-potprocessinvolvesepoxideintermediatesthatareopenedbyGrignardreagents'The of chiral products' method can be employed in the synthesis

PhMgBr

EtO:

CuBr- LiBr THF, -2OO

l . '" "-

L

' 'rnli, ( R.D., Forsyth'C.J' JOC 60,8122 1995 ' Pto: 3rdudri, F., Fiandanese,V', Marchese' G Ptm 3.rdudri, F., Fiandanese,V', Marchese' G" '--hommet, G., Freville, S , Thuy, V'' Petit' H ' ( II \owska-Pacewicka'K',Zwierzak' A' S 3-1-r '.'.ntrill, (1995t A . A . , S w e e n e y J, ' B ' S L 1 2 ' 1 7 t1995 Reetz,M.T., Kindler, A' JOMC 502' C5 ".-rpshutz,B.H., Hackmann,C' JOC S9"l1l- t1 'rtenta. g.K., Ila, H., Junjappa'H' TI 36' l9a(

Gri gnard reagentJcopper salts

I

-'

a-Diketones and a-ketoesters. oxalyl chloride reacts with two equivalents of , ingnard reagents in the presence of cuBr and LiBr to afford cx-diketones.2A similar -r.rction of the monochloride/estersof oxalic acid gives the o-ketoesters.3 A convenient approach to 4- and 5-oxoacids consists of analogous cu-catalyzed '!'rctions of cyclic anhydrides (succinic and glutaric anhydrides).4 Reactionof aziridines. As aziridines with an activating group on nitrogen (e.g., :hosphoamides)undergo electrophilic reactions, primary amines may be prepared by the ingnard reaction and subsequentremoval of the activating group.5Substitution at the side :rain of N,o-bis(diphenylphosphinyl)hydroxymethyl aziidine predominates, because a :t\)re reactiveleaving group is present.6

^ri

I

>' I

I i;

15 :. rr r lgg5). ^ r 5) . .r- '. I- , 1996).

=-.

Conjugate additions. The Kharasch reaction using CuI 2LiCl and MerSiCl as -.rtalystshasbeenevaluated.TAnother report8delineatessynthetic and spectroscopicaspects

t,B {-r.s7l ( 1995).

i the conjugate allylation. The replacementof a B-methylthio residueof enonesby Cu(I)-catalyzed reaction is both lo - nemo- and stereoselective.e'

. .1- l:l (1996).

w

Si' displacements. A method for the synthesisof 3,3-difluoroalkan-2-onesinvolves .irignard reactionof FrC:C(OEt)CflOAc and hydrolysisof the resultingenol ethers.rr

F

c-

il.

\

the addition reactions.r Suct crters by a two-step branching ' .rlkoxysilyl)methylmagnesium

I r),'^oec oEr

+ phMgBr

r . r

CUCN- UCI

Ph/v THF -2o" -> t1

I

oEr 60%

1,2-Diarylethenyl ethyl ethers.t2 Carbocupration of ethoxyethyne using ArMgBr, cuBr, and LiBr followed by Pd-cataiyzedcoupling with aryl iodides provides the products l0 examples,58-84Vo). KF Hzoz

tl

HQA,,"T - Y O B n :

PhMgBr

CuBr- LiBr THF, -2OO

Eto\

I

on

Eto.

> 1 l - ) : Pli\ Pti cuMsBr2I "t:H;"t

I

l-

ri :'-.r \\ ith N-tosylimidazoleand theo r. ': .,llrlic alcoholsare obtained.This [ ::: ,,rren€dby Grignard reagents.Thc

Cink, R.D., Forsyth,CJ. JOC ffi,8122 (1995). -Badudri, F., Fiandanese,V., Marchese,G., Punzi, A. TL36,7305 (1995). -Badudri, F., Fiandanese,V., Marchese,G., Punzi, A. T 52,13513 (1996). -Lhommet, G., Freville, S., Thuy, V., Petit, H., Celerier, I.P. SC 26, 2397 (1996). 'Osowska-Pacewicka, K., Zwienak,A. S 333 (1996). 'Cantrill, A.A., Sweeney,I.B. SL 1277 (1995). Reetz,M.T., Kindler, A. JOMC 502, C5 (1995). 'Lipshutz, B.H., Hackmann,C. JOC 59,7437 (1994). 'Mehta, B.K., Ila, H., Junjappa,H. TL36, 1925(lgg5).

X,

156

Grignardr€agentsy'nickelcomplexes

h,Iehta,B.K., Dhar,S.,Ila, H., Junjappa,H. TL36,9377 (tggs). f"Shi, G.-Q.,Cai,w.-L. SL37l (1996). "Kato, N., Miyaura,N. 252, 13347(1996).

Ketones.' The Grignard reaction of r \.1ones, including benzils, can be obtained u

Grignard reagentsi/nickel complexes. 18, 173 Si'displacements. 4-Alkenyl-1,3-dioxolan-2-ones undergo ring opening in the Ni(Il)-catalyzed Grignard reaction, furnishing allylic alcohols.l Allylic ethers are also reactive when there is a phosphine group to coordinate Ni.2 Note that Grignard reagents which can act as hydride donors give products of reductive cleavage of the allylic ethen without transposition of the double bond.3

OMe PPh2 j I ,' v coHrg ..

MeMgBr

1

,^\\,r,\

(phsp)2Nicr2 T H F , 2 2 0 ,1 8 h

(teen"

Indolines.d Nickelcomplexesmedrarc :h organoazides,resulting in indolines.

cuai? 7O"/" (Z:E > 49:1\

The Ni-catalyzed reaction solves the problem in ring opening of recalcifant oxabicycles.aAlkynyl dithioacetals that can be described as allene l,3-dication synthons give allenes.5

tx'

MsMgl

/

(dpps)Nicb P h H , 6 5 0 ,1 2 h

Ph

(PibPn A/t

Allylsilanes.g rte.SiCHzMgCl

Ph

Alkenyl

selenides are

in DME in the presence of rl

IHF as solvent gives lower yields.

C-Aryl-l2-glycopyranosi.des.6

Unsaturated glycosides undergo substitution by Grignard reagentswith either Ni or Pd catalysts. The opposite stereoselectivityof the two reactions is fascinatins.

{:ng, S.-K., Cho, D.-G., Park, C.-H., Namkmrg-)rdiuk, M.T., Morken, J.P., Hoveyda, A.H. JACS \t,rrken, J.P., Didiuk, M.T., Hoveyda, A.H. Il t '-.jutens, M., Ma, S. JOC 61,7246 (1996\. l rt

c*;

,F{rEp. 1,per-

ocooEl rFoku"u*u, T' T 52' 1953(1996)' H.,Tsuchimoto' S.-I',Furuya, Bu JC

-122; 18' 174 reagents/titanium(IY)compounds'14' 121 Grienard ""'til_iior"rr., alkynescanbe extended (Z)-alkenesfrom The methodfor generating the titanacyclopropene quenching On enynes' to conjugatedand methylene-skipped with DrO, dideuterioproductsareobtained' intermediates ""-^'rr;;;r;., andexposingtheadductsto co Adiing iminesto rhetitanacyclopropenes pyrroles' leadto 2.3,4-trisubstituted

1

.P.uf

ocooEr

x

R.

\

rPrMgB

l "7-"oot,

(tsProLT,

E(

Etp. -4t I '

t'\--1t' iPrMgX - (tsPrO)4Ti; 9":Pf

PhCH=NPr -soo-t -2d

en--{.*}iroe,1, Pr

Pt\

co

/''

,-\\ ph_(N) Pr 61%

Allylation,Allylhalidesareconvertedtoallyltitaniumcompoundsby ihMgBr/(ihO)oTi,whichcanbeusedforallylationofcarbonylcompounddand the reaction is highly aldimines.a with imines derived from a chiral cx,-phenethylamine, induction' l a exhibiting '3-asymmetric diastereoselectivefollowing the Cram pattern bis(t15-indenyl)titanium and diene a from Allyltitanium species are also obtained dichloride in the presenceof i-PrMgCl'5 Cleavageofallylderivatives.Acombinationof(l-Pro),TiandaGrignardreagentis protecting groups, such as TIPS' Perhaps useful for dJ-O-allyiation6 without affecting other moreinterestingisthatanallylgroupatthecentralcarbonofamalonicestercanberemoved acidic hydrogen of malonic esters by in the same way, indicating a new way to protect C-allylation.T The rapid reaction is carried Hyd.rodehalogenation of gem'dihalocyclopropanes'\ out in refluxing ether to give the monobromocyclopropanes' "-'--ai"trrtli"t.' -ate complexes effect anti-selecti.uealdolization (5 ii-iu. examples,12-8lVo).

Quenchingdr r 2-Iod.o-7,3-ilienes.r3 Kcl ,.Jrnefurnishes2-iodo-1,3-alkadienes .:tscles.

Thc n Functionalizeil cyclopropanes' gr alkoxide titanium and reagent . Grignard -:.iction).14With the use of ethylene carborlr . r ;lopropanone hemiacetals'l5An intramok

acooMe \

&r|c ""-

c€d9

(rPtQ1

I

t

Grignard reagentdtitanium(W) compounds

When a carbonateester containing an alkynel0 or allene Intramolecular acylation. unitlr at the proper length is submitted to i-PrMgBr/(t-PrO)4Ti, the multiple bond is metallated and becomes nucleophilic such that intemal attack on the carbonyl group results in O -+ C transfer ofthe alkoxycarbonyl group. Diethyl alkynylmalonates also undergo a

R. ,OH

X +)

rl'

?.-nten, F.,Magnusson, G. JOC 61,7463(1996t. '\lrrtinez-Grau, A., Cunan,D.P.JOCffi,8331 t l9J i:rgman,L., Gupta,V. CC 2515(1995). '{rm. S.,Jon,S.Y.CC 1335(1996). lrrm.S.,Lee,I.Y.,Yoon,J.-Y.,Oh,D.H. "/ACSI lt : 'len. 8., Skerlj,R.T.CJC72,2468(1994).

PhH

BursnsnBur

ao"/"

o^-{t""

rr

Hexafluoropropene-diethylamine. gem-Difluorination,' Togethelrith { 5-dimethylhydantoin, the combination of :;m-difluorides.

/

i:rimizu,M., Maeda,T., Fujisawa, T. JFC 71.9 rlg9

60 % (crs: trans 1 :4)

Cyclaalkanones,- o-Bromo thioesters and selenoestersgive cyclic ketones on photolysis in the presenceof (Bu.Sn)r. 162

Hexamethyldisilazane. 13, l4l; lE, I 77- I 78 Allylsilanes.r Allylic acetates and m by a Pd(0) catallsr:rmethylsilane derivatives presence :imperaturesand the of LiCl.

Hexamethyldisilazane

ETOOC\,/rcOOEr

EIOOC. ,COOEI ,,\

\

er)

Bu3snsnBu3

/

.-\

hv (3oonm)

cosPh

o 85"k

| .::.-:.nt catalystfor the rearrangementin a | . < - \..lnlples. 53-97Vo). r...

R:-

Synthesisof oxime etherc.S Phenylsulfonyloxime ethers accept free radicals seneratedfrom organohalides and subsequentlyexpel the PhSO, unit. Thus, the process constitutesa chain extension by a masked acyl group.

.x)6r.

oEt

. .rrc'dby CprHfClr-AgClOo to reactwith

P{

o-' -: u:.

l-

Me3SnSnMq hv

o4

oEt

(Y

oEt

"nsg -N-oBn R ,

lll-144;18, l'15-176

'H

\_J

'a.

FN-oBn R R = H 88o/.

i .rll\ I group to a sugarwhen it is treated

and telluridesundergo )r-- . -..i()rganoiodides i: .': '.rdc'a hydrogenatomthe configuration .rr:' .:rr'J.rThere is a distinct preferencefor r '- : ',,u crclopentane.3

H,,,T\

R=Me

78%

With (PqP)4Pdas a catalyst,hexamethylditin vic-Bis(trimethylstannyl)alkenes.6 (21 examples, andN,N-dimethyl-2-alkynamides homolyticallyaddsto alkyl 2-alkynoates 61-95Vo). G. JOC 61,7463(1996). Ponten,F., Magnusson, -Martinez-Grau, A., Curran,D.P.JOC 60,8332(1995). 'Engman, L., Gupta,V. CC2515(1995). 'Kim, S.,Jon,S.Y.CC 1335(1996). tKi., S.,Lee,I.Y.,Yoon,J.-Y.,oh, D.H. JACS118,5138(1996). Tiers, E., Skerlj,R.T. CJC72,2468(1994).

'-:-:-

Hexafl uoropropene-diethylamine. gem-Difluorination.' Together

1,3-dibromoN-iodosuccinimide or with 5.5-dimethylhydantoin, the combination of reagents converts 1,3-dithiolanes into

s-:

' ,v o/ / /

f-IePh \

F_

sern-difluorides. T. JFC 71,9 (1995). Shimizu, M., Maeda,T., Fujisawa,

60'/. (cls: trans 1 :4\

.clenoesters give cyclic ketones oo

Hexamethyldisilazane. 13, l4l; 18, 177-17 8 Allylsilanes.' Allylic acetates and trifluoroacetates are converted into the rimethylsilane derivatives by a Pd(0) catalyst. The reaction of acetatesrequires higher remperaturesand the presenceof LiCl.

164

OAc

Pd(dba)2,LiCl +

crrruD

+

MesSiSiMe3

c7H15,vSitvte3 DMF 81"k (E: Z 95 : 5)

1000. 40 h

'Tsuji,

llulla-
rt 90% (anti: syn 98:2)

174

Iodine

RCHO

+

oMoM ,' v'SnBr. ^ \

Bu35nCl

Inc[ "

\

Me,co -zao-> rt

R'

?" "

8L

Bu-B(Hx)3 Bu35.

\'/ Y oMoM

Lt

74- 83"/"(anti: syn 84-98: 16-2)

Admixture of alkynylstannanes, aldehydes, trimethylsilyl chloride, and InCl3 in acetonitrile at room temperatureresults in the formation of propargyl silyl ethers.aIn the synthesisof homoallylic alcohols, simple allylic halides can be used to form the tin halides

a-rr! Allylmalonic Heterocyclizntion. .rcorporating iodine, giving 1-bufyrolactoft! a 'ley are treated with I, in dichloromethanear r The stereoselectivity of pynolidine fomr ;reatly affectedby a base.ro

in situ in water.5 Mukaiyama aldol and Diels-Alder InCl" in water.

reactians.

Both reactions6'7are catalvzed by

W'n NHTs

rTrost,B.M.,Livingston, R.C../ACSf 17,9586(1995). zMarshall. J.A.,Hinkte,K.w. JOC 61,105(1996). 3Marshall. J.A..Garofalo.A.W. "/OC61, 8732(1996). aYasuda, I., Baba,A. TL36,9497(1995). M., Miyai,T., Shibata, 5Li.x.-R..Loh.T.-p. TA7, ts35(tgg6). "Loh,T.-P.,Pei,J.,Cao,G.-Q.CC 1819(1996). 7l-oh,T.-p.,pei,J.,Lin, M. cc 2315(tgg6).

+ K2CQ

Iodine. 13, 148-149 ; 14, l8l - 182; 15, l'72- 173; 16, 182; 18, I 89- I 9 1 The conversion of alcohols to iodides with inverted configuration is Alkyl iodides.' accomplishedby heating with iodine in an alkane solvent. The reaction in refluxing methanol cleaves p-methoxybenzyl Cleavage ofethers. ethers (10 examples,T5-91Vo)2.Benzyl ethers are not affected,but r-butyldimethylsilyl ethersare deprotected.l Dithioacetallacetal exchange." Iodine in 1,2-ethanediol is effective for this transformation, which is particularly valuable for the synthesisof bissilyl ketones.

ogivezen

MeSrSiMezPh MeS'

SiMe2Ph

HOCH2CH2OH

O

SiMe2Ph

80% HOAc

or.

I

l L l

o'"OH H

DMSO, 230, 2 h

\

I

,,---1 \ r o

H

rFrigerio,M., Santagostino, G' JOC 60'7272(1995)' M., Sputore,S.,Palmisano, rCorey,8.J., Palani,A. TL36'3485(1995).

Iridium chloride. Isoxazolidines give perhydrooxazines by IrClr-catalyzed Reductive insertion.t are obtained by insertion of CO into the N-O bond. Interestingly, perhydrooxazin-2-ones changing the catalyst to [Rh(cod)C1]2. analogousprocess' Note that the cyclization of hydrazones2with an alkyne moiety is an a hydrosilane' It gives heterocyclesby methylene-stitching,using Irr(CO),t' CO' and

MeOOC\//:

rr : -.::r()n of B-ketoestersis readily perr - .remples,50-807o). !r.:.:. J new way for the conversionof

1.3

l l

"ox Y ty''.,-ot

MeOOC

r.-': \

1

,a\l\

\

lr+(CO)rz , CO - AuMqSiH

N-NMe2

MeCN 10 atm 1400, 20h

,-SiMezBut

rrleOOC'l tvteooc/\=--rN-NMe2 53%

rKhumtaveepom,K., Alper, H. JOC 60' 8142 (1995)' rchatani, N., Yamaguchi,S., Fukumoto,Y.' Murai, S' OM 14,4418 (1995)'

,

:: ': SiCl.-NaI in situ, shows chemo' [:: - .rturatedketonesare produced. r. '. .r7.229'7 (1996).

Iron. to secondary Reduction of N-o compounds. Nitroxides and nitrones are reduced of acetic presence In the amines with Fe-HoAc without affecting other functionalities.r (11 examples, anhydride, nitroalkenes are converted into enamides at reflux temperatures 60-817o).2

Iron(III)

chloride

NHAc

[-l'-*o' \ttz

Ac2O- HOAc A 2-5h

65v" Reduction of azides.3 Primary amines or amides are generated from ArN, and ArcoN3, respectively, on treatment with Fe and Niclr.6Hro in THF at the temperatureof lce. 'Sar, C.P..Kalai.T.. Baracz,N.M., Jerkovich,G., Hideg,K. SC25, 2g2g(Igg5). "Laso. N.M..Quicklet-Sire, 8., Zard,S.Z.TL 37,1605( I 996). 'Baruah, M., Boruah,A., Prajapati,D., Sandhu,J.S.,Ghosh,A.C. TL 37, 4559(l996it. Iron(III) chloride. 13,133-134:14,164-165;15, 158-159; 16,167_169.190_19t:tZ. 1 3 8 - 1 3 9 : 1 81. 9 7 Deben4ylation l Benzyl ethers ofcomplex oligosaccharidesare selectively cleaved on exposure to Fecl, in cHrcl, at 0' without affecting acetates,benzoates,phthalimides, acyl amides, and sensitive glycosidic linkages. Glycosylation.z o-Glycosides can be synthesizedfiom unprotectedglycosyl donors by using FeCl, as a catalyst. Hydrationof arylalkynes.3 Fecl, with water constitutes a specific system for converting arylalkynes to ketones. oxidative cleavage of cyclopropyl trimethylsilyl ethers. 2-cycloalkenones are obtained from bicyclo[n.1.0]alkan-l-yl trimethylsilyl ethers.awhen a double bond is presentat a suitable distanceto interact with the p-radical, cyclization occurs.5

MesSiO,,,,4 ..1,",H

o,, Fecrs

-

l,-r.2".._/ l r -

.l::|,'

H fcl

()-^\r--( t ) \.rfv H 64/"

2,2'Dichloro-7,3-indanediones.6 1,4-Naphthoquinones undergo ring contraction and chlorination on reaction with FeCl.-HClOo in HOAc at room temperature.

ArNOz -+ArNHz.'

1

The FeCl.-catall

zine.

:Rodebaugh, R., Debenham, J.S.,Fraser-ReidB f -Ferrieres, D. Il 3t1 V., Bertho,J.-N.,Plusquellec, 'Du-i-o, M. JOMC 522,303(1996' J.P.,Postel, 'Booker-Milburn, D.F. f Sl. 135 K.I., Thompson, 'Booker-Milburn,K.I., Thompson, D.F. JCSrPl, :. 'Singh, R.N. 7L 35,3753( l991r P.K.,Khanna, Boothroyd, S.R.,Ken, M.A. f2,36,2411(1995'

{ Isocyanocyclohexane)gold(I) chloride. l.-l-Dt Imidazolines and isoxazolines.

and amideswith N-tosylirninesrand aldehrdc heterocycles.Interestingly, cis-imidazolinesa trans-iridazolines are obtained on base 9 9 % ( c i s :t r a n s 9 0 : 1 0 )

rHayashi, V.A.' Uozumi,Y. TL37'4969(1996)' T., Kishi,E., Soloshonok, 2su*u.ur4 M., Nakayama, Y., Kato,T., Ito, Y. JOC 60' l'127(1995)'

t )

-.-_4t H

64"/"

t--.:', nes undergo ring contraction 0 i- .:l rt)ofl temperature.

Isocyanuric chloride. 18, 199 The rapid oxidation of aldehydes to methyl esters in the presence of oxidation. -937o)'t Acetals are similarly pyridine and methanol is preparatively useful (9 examples,67 converted to esters.z rHiegel,G.A., Bayne,C.D.,Donde,Y., Tamashiro'G'S',Hilberath,L'A' SC26'2633(1996)' 2Benincasa. U.M. SC25' 3463(1995)' M., Grandi,R.,Ghelfi,F.' Pagnoni,

o

. -fl.,c| i l ---\

lr X br \\n

Isocyanuric fluoride. Activation of carboxylic acids. The formation of an acid fluoride and its immediate treatment with NaBHo accomplishesthe reduction of an acid to an alcohol. y,\-Unsaturated ketones.Z The fluoride is useful for promoting the transfer of the alkenyl group of an alkenylboronic acid to enones.

r82

4-Isopropyl-2-oxazolin-5-one

F

/\A/tr(o*),

*

ruAr.,t

-y

i l l FAN-AF

Ph

r

cH2ct2 A

o

-1

'w"(Y'n o

H

N\rO

o +

:\

E:J l

cHo

(1) 'Kokotos, G.,Noula,C. JOC 6l,6994(1996). 'Hara, S.,Ishimura, S.,Suzuki,A. S1,993(1990.

Barco.A., Benetti,S., De Risi, C., Pollinr. G P

Isopinocampheylchloroborane. Asymmetric cyclic hydroboration.t As illustrated in the following equation, the facile accessibility of this reagentby in situ reduction of the dichloroborane derivative with MersiH and the high optical yield of (+)-trans-decaloneprepared from the hydroboration route suggesta general approach to such ketones:

Me3SiH Me3SiH

BCl3 pentane, -7d

> 99% ee

I unruo

V

MecHo,

", (-.1 -

I

\

-

\

l(r'o

\--'

+

M€ocHcr2: H2O2 - NaOAc

l

fr

>99%de/ee

lBrown, H.C.,Mahindroo, V.K.,Dhokte,U.p.JOC 61,1906(1996). 4-Isopropyl-2-oxazolin-5-one. Formyl anion equivalent. Under mildly basic conditions, (1) acts as nucleophile toward carbonyl compounds and undergoesconjugate additions as well.

4-Isopropyl-2-oxamlin-5-one

-1

llllle

H N*b * (1)

Er3N

)

+

l*o

o

\-1l / / \

57' Hcl

il.t,,b

l

r

n )

cHo

r

cHo I I cHo 38%

72"/"

rBarco,A., Benetti, S.' De Risi, C.' Pollini, G'P', Spalluto' G''Zanitato'y 'TL34'3907 (1993)

s::.:r-J in the following equation, the c: : thc dichloroborane derivative with i: ' , treDilr€d from the hydroboration

a)

o'€ I mtno

V

u; E-

r-

r'. - -.,nditions, (1) acts as nucleophile rs.,:- .,.iJitionsas well.

r83

Eto\Y'o *oa

Eto

Lanthanum(Ill) isopropoxide. lT, 160; 18' 201 Heating an ester in another alcohol in the presence of Transesterification.l for exchanging the alkoxy group' method La(OPri), is a simple

I

Oxidativecleavageof ftamino ala leadto eitheran aldehydeor a nitrile'

tokano,T., Miyamoto,K., Kiji, J. cL246 (1995).

"",-1{oH

Lanthanum(Ill) perchlorate hydrate. pGlycosytation.Trimethylsilylethersareadequateglycosylacceptors,lwhereasa of cr'-mannosyl combination of La(ClO)o and Sn(OTf), is effective for the glycosylation fluorides.2

f*^

- ,o

Ph

rKim, W.-S.,Hosono,S., Sasai,H., Shibasaki, M. TL36' 4443(1995)' 2Ki., W.-S.,Sasai,H., Shibasaki, M. TL37"7'797(1996)-

Lead. Lead is capable of promoting (2-alkoxya-M ethy Ien e' Y-b utYr olacto n es.' products undergo lactonization on contact with The carbonyl)allylation of aldehydes. CF"COOH.

oH ,,

RcHo * t'VA"oo=,

NH4CI THF - H2O

t i l n/V\cooet 61 - 97%

which Reduction of conjugated carbonyl compounds.Z The Lindlar catalyst, conjugated of the the saturation promotes activity, catalytic of a regulator as contains Pb double bonds. rzhou,J.-Y.,Jia,Y., Yao,X.-B.,Wu, S.-H.SC26' 2397(1996)' 'Righi, G., Rossi,L. SC 26,l32l (1996).

Lead[V) acetate. 13, 155- I 56; 14, I 88; 16, 193-194; 18, 201-202 Squaric acid derivatives undergo cleavageofcyclobutenolones.l cleavageto give lactones. 184

IYamamoto, Y., Ohno, M', Eguchi' S JICS :Jayaraman,M., Nandi, M', Sathe' K'M ' D

Lipases. 17, 133-134: 18' 202-2Or HydrolYsis. 1,1'1-Trifluoro-l-: chloroacetates'rald corresponding the

t alkanols have also been successfulll menthlof resolution the is shown in s group is retained.3Selective hydroll usci been has a chiral diol,a which r tS)-chromanethanol' which is an reso 6-acetoxymethyldihydropyranis (PPL). These can be used to

2,2'-bis(phenylthiomethyl)dihydropl' for 1.2-diols.5

i

o

Lipase (Atrsr

!,r o\,* oxidative

,,\

6n.

pH 7 ptF6!, 30o

Lipases

o ErO

EtO

/o

Pb(OAc)a

)*o"

EtO

p

tt ^/"--{

PhMe

I

/(

\_

Eru

-.OAc

/

rt. t h

5'l%

x:.:r .rlcohol in the presence of ! i:

,Llp.

can Oxidativecleavageof ftamino alcohols'z Adjustment of oxidation conditions teadto eitheran aldehydeor a nitrile. R",,,, ,,,,cN

TI

whereas a rlrcosyl acceptors,r gl;-cosylationof cx-mannosyl

}_NR

o'

,, NHZ a ' . T : P H + Pb(OAc)a )-Na

- 100./"

R",,,, .,,,cHo

Ph

fl /r-NR ct' 80%

of

promoting

(2-alkoxy-

rYu.urnoto,Y., Ohno,M.' Eguchi,S JACS117,9653(1995)' tluyu*.un,.fuf., Nandi,M., Sattre,f.U., Deshmukh,A'R'A'S'' Bhawal'B'M' fA 4' 609 (1993)'

.tctonizationon contact with

oH ,,

.)tA"oor, 61 - 970/o

L-'i:i

Lindlar catalyst, which .aturation of the conjugated

Lipases. 17, 133-134:' 18,202-204 hydrolysis of Hyd.rolysis. 1, I ,l -Trifluoro-2-alkanols are resolved through enzymatic 1,1,1-trifluoro-3-phenylthio-2the corresponding chloroacetates,ralthough the acetatesof A useful selectivity alkanols have also been successfully resolved by a similar procedure.2 as the menthyl ester is shown in the resolution of menthyl 0,-acetoxy-0,-ethylthioacetate, provides group is rerained.3Selectivehydrolysis of 1,5-dibenzoyloxy-3-methyl-3-pentanol (R)-mevalonolactone and an a chiral diol,a which has been used for the synthesis of for vitamin E. Racemic block building (s)-chromanethanol, which is an important porcine pancreatic lipase by isomers 6-acetoxymethyldihydropyranis resolved to the chiral (PPL).Thesecanbeusedtoprepare2,2,-bis(halomethyl)dihydropyransand protecting and resolving agents 2,2'-bis(phenylthiomethyl)dihydropyran, which are useful for 1,2-diols.5 a

=

, Lipase(AmanoPs)

1g;rr1-202 .:::rratives undergo oxidative

pH 7 phosphate 300

t

t

O

l

l ,..^,.\

U

,,st, : onc

48% (>95% ee)

t

O

(-.J.,....,\se, I I OH

186

Lipases

The resolution by enantioselective hydrolysis of cyclic carbonates6 and 2-oxazolidinonesTis particularly interesting with respectto the latter class of compounds, in which the estergroup is attachedto a side chain while the stereogenic center is in the ring.

Diketene is a recently employed t enantioselective esterification of hemrd interesting. Note that the greater-th:

hemithioacetalsare recycled by dissocian

roH

7-OcOEt

r- Nt l F n Ph',^-ci

lipase

r-Nr. l F o

|Pt20 rt,

f-ocoEr

*

Phl--o

-N

l F o

A.n

Ph"'-o

MeO'Y

3h

+

HS.n \2/

OSiEt3

tl 42o/o(75ok eel

A v

46% (70% eel

crosslinked crystals of candida rugosa ripase are highly efficient catalysts for resolving racemic esters,8whereas ppl- immobilized in microemulsion-based gel has been used to hydrolyze one of the polyphenolic perpropanoates.e Actually, symmetrical diacetatesare readily cleaved to provide the monoestersby ppl.lo Resolution by transesterifuation. A procedure for the large-scale preparation of (ls'2s)+rans-2-methoxycyclohexanol, which is a key intermediate for the synthesis of tricyclic BJactam antibiotics, has been worked out.lr Monoprotected 1,2-diols and acetals of a-hydroxy aldehydesafford chiral acetatesby the lipase-c atalyzedtransesterification.12 q-Ketols are also resolved.13Dimethyl meso-2,5-dibromoadipate is readily desymmetrized by the transesterificationprotocol, permitting the synthesis of chiral cis-2,5-disubstituted pyrrolidines.la

PLL = Pr

Chemo sele ctiv e trans esterifitatiort (and deacylation) of carbohydrateshas br The lipase-mediar Esterification.

l5 rnin.).22Four lipases immobilized in catalyzing esterification.z3 Resolution gives access I -cyclohexenecarboxylate spirocyclic alkaloids:24(+)-nitramine, r+ I The resolution of 2-methylalkanoic r using a long-chainedalcohol.25

Amidation of esters. Benzyl ra formation with simultaneousresolution o MeOOC U--r .COOMe V. \: / : PPL Ar

gr

MeOOC z--r .COOBn R.NH2 V \,/

: : Br 6r

BnOH

PPL = porcine pancreatic lipase

f_l

Meooc^N

cooBn

I Ph7""H

':r.COOlue

s6% (g9o/" de)

\"oo""

K2co3 PhH - H2O

62"/"

arn ;

A double-enantioselectivesynthesis of carbonatesand carbamatesusing C. antarctica Iipase is eminently successful.15

I f f

pnAoAo\

+ Ho"\

CoHtg

CAL=

hexane,32 h

Qanlida antarctica

lioase

Ph'

'o',t\

,/\

b'

'cuH,.

41Y"conv. 88% de, 98% ee

The enzymatic reaction is promoted by microwave.16Significant effects of acyr groups on the enantioselectivetransesterificationhave been observed.lT

'Yonezawa, T., Sakamoto,Y., Nogawa. K. l' 2shi-i.u, M., Sugiyama, K., Fujisawa- T. 8C 3Milton, J., Brand, S., Jones,M.F., Ralrrr. C -{ aMizuguchi,8., Suzuki,T., Achiwa, K. SL 5L"y, -9 S.V., Mio, S., Meseguer,B. ,!l 787. oMatsumoto, K., Fuwa, S., Kitajima, H. Il t TWakamatsu, H., Terao, Y . CPB U,261 r | 99 ol-alonde, J.J.,Govardhan, C., Khalaf, N.. \tr ( 1995). eParmar, V.S., Pati,H.N., Sharma,S.K.. Sinci (1996).

Lipases

d: . -i\ of cyclic carbonates6 and r..:.i.r ro the lafter classof compounds, '* :. : the stereogeniccenter is in the ring.

OH

'-o

media.rs're The Diketene is a recently employed esterification agent in organic in situ, is most formed are enantioselective esterification of hemithioacetals,2owhich unesterified the that interesting. Note that the greater-that-5}Vo yield indicates components' hemithioacetalsare recycled by dissociation into the original

TOCOEI

o

I

t /N. \

+

U

,t H + MeO'\y"

Ph""-o

HS.n \.2 OSiEtg

tl

t'

-:

46o/" (7O% ee)

: ee)

o

PLL- cHz=cHoAc

Jf.

FBuoMe, SiQ 3oo, 11days

.S. n 6O.

83% (90% ee) PLL= Pseudomonas ftuorescenslipase

.re highly efficient catalysts for gel has been zr.: r microemulsion-based a rt

f

I

l

(-r^---",/ '

\

I

LDA/THF

-

7

*

\

:c-,

.

l

/

6r"

oPO(oEt)2

91"/' 'i LoA / rHF

(EIO)2OPO

*-OMe Ph

o

Ph

LDA/ THF -z3o

'Y ,/A:.,N(SiMeg)z

Ph-

Y OH 89%

can be coupled to a route6 to tetrahydropyridines Theaza-12,31-Wittigrearrangement used as the base for the BuLi was ^*ttt Wittig olefination of 2-acyl-itidin"'' demonstration'7

25o

I

*,-OMe 'i -.

pl Ph.

P(

LDAITHF.

/ ,

bsiMe2Bu'

2

5

o

alkenYl sultn AlkenYlsibnesanil p-silyl sulfo where,as reanangement'l2 to give alkenylsilanes"'

Ph

.COOBut

( -!

,.9

LDA >

tt "n

rHF, -7Bo

I 2'\ l l /-tt coogu'

^

csHrz\X.

.SiMe3 SiM%

H

63"/"

undergo by Diels-Alder reactions Dihydrothiopyrans.prepared ls Cyclopentenes.E of LDA/HMPA' The reactron atlyl aniong in the presence (via thiolati ring contraction diastereoselective'

P

SiMe3

j'.so2Ph -J Ph/

Lithium diisopropylamide

w-

cooEt

, '

\ l

-

T S N H O \ ,

Na-Hg -

-

: i l \ / pnMoA

195

-n-cooEt

LDA/ THF-HMPA;

)ilcooet

- $ +

./\-'S

SMe

l|--. 74o/o

SMe ( 8 : 1 ) 87"/o

r.'adily promoted by LDA. The )br':r.,,'rnazolesto give B,y-unsaturated ' -..1 Benzyl and allyl hydroximates r \ .::.. c'thersof cr-ketols.5 s ,::

A

Ph

--:

>'/

. -

f

(o

91"/"

F

*-OMe r. _Ph

Allenes. Substituted allenes are prepared from ketones via elimination of the enol to phosphates.eInterestingly, enol triflates tend to give alkynes. The method can be applied elimination' undelgo also ethersrt enol Silyl protected aminoalkenyl phosphates.r0

a^)

a

-J

\

w I

al

LDA/THF .....'-------_

\

a \ l--.)

-7Bo

|

oPo(oEt)2

62%

(EiO)2OPO LDA/ rHF \ N(siMe"), -'-'- -"'' /,' \,/

? . Y

25o

I

\tts'"".r,

70"k

OH 89'/"

t.::

Ph.

/

p(

bsivte2But

:

rDA/rHF

25o

Ph.

,Li

Ph'

Li

Me2Si(H)Cl

Ph.

/SiMe2H

pr(

siMe2H

.-.,,Jropyridines can be coupled to a ,.ruallv used as the base for the

Alkenylsilanesand alkenylsulfunes. I, I -Disilylepoxides undergo an unusual whereasB-silyl sulfoneslosethe sulfonylgroupon treatmentwith LDA rearrangement,l2 to givealkenylsilanes.r3 Ph

..>

L

4r.rAcooau, n

..r -SiMee csHrz\ix_..SiMe3

LDA

;l

63q.

rr.:.-: 'i Diels-Alder reactions undergo p.r .:':r.. of LDA/HMPA. The reactionis

SiMe3 I CeHfl\/\,,.SiMe2OH 9 0 " / " ( E : Z1 : 1 1

SiMe3

LDA

,n/..",,so'Ph

THF A

,h"\,"siMt' 79%

196

" 1",.t'1Tltl;t-l'l;lTt creary.

Lithiumitiisopropylami(

'Davis. F'A ' ReddY'u'v ' rt

Thebase-mediatedtransformationofepisulfonesintoalkenylsulfonesisstereoselective'

-'"il-f#l;#

promote successtulrv ;**, .-:Xor LDAinether

i:;ff;"t".

thedecompositionorr'yoru"on"sderivedfromN.amino-2-phenylaziridine.(Z)-Alkenesare havebeenreported' the major Products' synthesesofpyrrolesl6and B-thiolactamslT Heterocycles' New

of the A s y n t h e s i s o f t h e * i l ; l i i v ' i o u " i ' i n*"" - tatp'o'onution u t o ' " ' a n e l iismnot i n aatt ithe o nn-carbon ofan *"In**ot'' N-toluenesulfinvf-i'ioinlii estergroup'

LDA/ THF

cHo AruH

L-

//

-78o-> 25o HCI/ cH2cl2

BJc

PhCOOMe +

HC(=S)NMe2

-7Bo

.bt\..

(-Jl

*

camphorsulfonic aod

\

/1.--

Licto4- Et2o

Intramolecular

o. -o

a\t-\ t t t

l

H

30 min 867"

cFscooH Licto4- Et2o t h

/-rfr

\-< ) H4 f "

OBu'

other cycloadditions. A [3+2]-cycloaddition involving a benzoquinone and an alkene to give 2,3-dihydrobenzofuran derivativesf and an intramolecular [4+3]cycloaddition to provide functionalized polycyclic compounds,r0are further demonsrarrons of the utility of Licloo.oEtr. The reaction of aromatic or o,,B-unsaturatedaldehydes with acid chlorides proceedsvia ketenesand then 2-oxetanones.ll

LIOO.

Etv\ rt6.

Rearrangements and ene reactions. Thc vinyl ethers as catalyzed by LiClOo.OEh har p ionize to give stabilized carbocationssuch as l-fi to undergo this type of reaction.l2

Diels-Aaer reactions. compounds that give an oxygen-stabilized allyl cation are super-dienophiles in the presence of Licloo.oEt' The method obviates the difficulties experienced with the low reactivities of 2-cyclohexenones] An intramolecular variand

o. -o

,Ph

6J

Licro.-€+ n

6.

ene reactions are readily crrah

lsudhu, R., Narasimhan, K.M., Saraswathy,V.G.. Sa 'Bohm, G., Waldmann, H. I-4,613 (1996). 'Ipaktschi, J., Eckert,T. CBl28, ll71 (1995). -Giovannini, R., Petrini, M. SZ l00l (1996). 'Saraswathy, V.G., Sankararaman, S. J CS(P 2 ) 29 r I I osaraswathy, V.G., Sankararaman,S. "/OC 60. 501{ r I 'Grieco, P.A., Collins, J.L., Handy, S.T. SL I155 ( lF ocrieco, P.A., Kaufman, M.D., Daeuble, J.F., Sairo. \ J., Ryu. Y.. Chiba. K.. Tada, M. "/CRrSlll{, ,-Asano, '"Harmata. M., Elomari, S., Barnes,C.L. JACS llt. :t IlArrastia, I., Cossio,F.P. TL37,7143 (1996). ''Palani, N., Balasubramanian,K.K. TL36,9527 (Sq ''Sarkar, T.K., Nandy, S.K., Ghorai, B.K., Mukhegec.

Lithium telluride. vic-Dinls-s alkenes,t After derivatizatia to eliminationby LirTe at roomtemperature. rclive,D.L.J., Wickens, P.L.,Sgarbi, P.W.M. JOC61

LitNum tclluride

201

F-

11

t* (' ' r, F-r.O. epoxides are converted to h :'.::. and trichloroimidates undergo i: -' rrridesand phosphatesare inert. s : [!.rones with alkynyllithiums and Lr( , r. OEt have been compared.3The u:

.x

t

LDA

\-\_/. o . o

Ttcl

r. .-'.: nirroalkenesinvolves silyl group

LiClOa Et2O- Et3N n

cl. ',

52% (overallyield)

-/

Ph

pl /

x o+

LiCtOa-Er2o Et3N

,'t rhe benzenesulfonylgroup of

-\ .:,,1reactionscatalyzedby LiClOo.OF4 f : -. .rnddimethoxyacetalsof aldehydesi

\

/-\( \-\_/.o- on

/

'

Ph

H

rt,6h 71%(E:Z4:6\

Rearrangementsandenereactbns. The fl.3]-reanangement of hindered allyl vinyl ethers as catalyzed by LiCIO'OEI, has previously been reported. Allyl ethers that ionize to give stabilized carbocationssuch as 2-furylalkyl and 2-thienylalkyl ions are found to undergo this type of reaction.r2

g:.: .,:r ()\\'gen-stabilizedallyl cation are E: . :c method obviates the difficulties

W,

f.' -, - :t()nes.rAn intramolecularvarianf

OJ

Licto4 - Et2O rt, 6h

n r 'o^1 ,P 50v"

Intramolecular

O. rO !'

,t^\.'\

l '\.4\-,-\

?:,

t l

H

f

86%

---\

/

k*) x..

-'--\:

87"/"

':r,rlr'1nga benzoquinone and an l:.-. end an intramolecular [4+3]:. ,unds,r0are further demonstrations 'r d.p-unsaturated aldehydes with lT :' c'.:' : t ' . . I

ene reactions are readily catalyzed by LiClOo dispersed in silica gel.13

'Sudha, R., Narasimhan,K.M., Saraswathy,V.G., Sankararaman,S. JOC 61, 1877 (1996). 2Boh-, c., Waldmann, H. I^A,613 (1996). rlpaktschi, J., Eckert,T. CB 128, I l7l (1995). aGiovannini, R., Petrini, M. Sl, l00l (1996). ssaraswathy, V.G., Sankararaman,S. J CS(P 2) 29 (lg9 6). 6saraswathy, V.G., Sankararaman,S. "IOC 610,5024 (1995). 7c.i".o, P.A., Collins, J.L., Handy, S.T. SL 1155(1995). ocrieco, P.A., Kaufman,M.D., Daeuble,J.F., Saito,N. JACS 118, 2095 (1996). 'Asano, J., Ryu, Y., Chiba, K., Tada, M. JCR(S) 124 (1995). 'oHu.rnutu, M., Elomari, S., Barnes,C.L. JACS 118, 2860 (1996). "Arrastia, I., Cossio,F.P. TL37,7143 (1996). f 2Palani, N., Balasubramanian,K.K. TL36,9527 (lgg5). ''Sarkar, T.K., Nandy, S.K., Ghorai, B.K., Mukherjee,B. SL97 (1996).

D , -

Lithium telluride. vic-Diols-+ alkenes.r After derivatization to the dimesvlate. a vic-diolis amenable to eliminationby LirTe at roomtemperature. rclive,D.L.J., Wickens, P.L.,Sgarbi, P.W.M. JOC61,7426(1996).

Lithium tri-s-butylborohydride (L-Selectride)

(LTMP).13,167;14,194-195; Lithium2,2,6,6-tetramethylpiperidide l7 , 17l-172; 18,220-221

LiBH(s8ub

I-Hydroxyalkylmaleic esters.r LTMP can initiate a Michael addition to maleic estersto give adductsthat are reactive toward carbonyl compounds.The expulsion of LTMP

THF, -7f - n

completes a reaction cycle similar to the Baylis-Hillman reaction.

OH

LTMP

(cooet

FO

I Ph7\"'cooet

-78o -> rt

cooEt

Chiral 2-hyitroxyalleylaziridines.l T is high. .'ertain2-acylaziridines

cooEr 51%

Ph

^* Interring-directed lithiation.z With LTMP at _-40" or -70o, 2,4'-bipyridyl is lithiated at the C-3 of the 4-substituted pyridine ring, owing to the directing effect of tlre secondnitrogen atom. Thus, selective functionalization (such as by stannylation and Heck

fr

L'E

LV\rn H

, .7tr

reaction) at that position is readily achieved.

Reductive cyclization.4 2,7-Nonadr ;yclohexane derivatives. With proper ple rerpenesynthesisis readily preparedb1 ttus

IHurro*uen, D.C.,Poon,H.S.?52, 1389(1996). 2zolrewicz.J.A.. Dill. C.D. T 52. l4r';6gOgg6i).

Lithium tetraorganoindate. Allylation.'Coupling of the organic residue of Li(InRo) with allylic halides occurs at room temperature.Products that include 1,5-dienesare readily formed, and thus, the method is applicable to the synthesisof rosefuran and sesquirosefuran. 'Aruki, S.,Jin, S.-J.,Butsugan, Y . JCS(PI ) 549(lgg5).

Lithium tri-s-butylborohydride (L-Selectride). Reduction of the C=N bond.t The highly

stereoselective reduction of Ndiphenylphosphinoyl iminesr and O-methyl u-(p-toluenesulfinyl)ketoximes2 leading to amino derivatives are reported.

,

-

\'J

/

\

L

i

/:ry pn)p=o

! B

H

(';

rHF, ,t

s

J

A

\

U

u

)

.

/

,rNlH pn)p=o

J

*\

(>97 : rt

ro1ror,,\,,L ' | | Y,,.,oBn

9 8 % ( d s> 5 0 : 1 )

\ \Iagnesium monoperoxyphthalate t Il Baeyer-Villigeroxidotion. Thc \{MPP as reagent is mediated by acao

Magnesium rnonolrcroxyphthalate(MMPP)

l. : ll.O couple reduces carbonll J'r(':r.'.c'nce of an allyl halide, homoa\l ; . : :..rlides(alkyl, aryl, benzyl, etc.) RI rl a'

7l 19(1995). r i .'t.-16. S.M. Ta tl' h . ..n Geel,T.A.P.,Stratton,

effected

is

r

::.rnsformation

I t

LR , S 2 t 8( 1 9 9 6 ) '

b

Dieckmann anit claisen condensatians. Dieckmann cyclization5 and claisen .-ondensationof N-acylpyrazoles6 are catalyzed by MgBrr-RrN. Note that a practical .y'nthesisof o-acylamino-p-ketoestersemploys MgClr-Et,N to induce the reaction between .rlkyl hydrogen (acylamino)malonatesand acyl chlorides.T G.G.,Baldwin,J.E.7 53, 215(1997). Haraldsson, :vede.js,E., Daugulis,o. JoC 61,5702(1996). 'Righi, G.,D'Achille,R.,Bonini,C. TL37,6893(1996). 'Charette, A.F.,Mellon,C' TL36' 8557(1995). A.8., Benslimane, 'Tamai, S.,Ushirogochi,H., Sano,S.,Nagao,Y. CL295 (1995). 'Kashima. K. JHC 32,1775(1995). K., Fukusaka, C., Takahashi, Krysan,D.J.TL 37,3303(1996).

Ilagnesium methoxide. 18, 227 Selectivedeacylation. By using Mg(OMe), in methanol, it is possible to remove primary acetates in the presence of tertiary acetates.rFor different esters, the order of reactivity to this reagentis p-nitrobenzoate > acetate> benzoate> pivalate'2

18.226-22-7 r .i.: . .r!B of benzyl ethersof o-hydrox;-

l-r

Mg(OMs)2

Ho,.

MeOH

Ir .:.j .r tertiary amine (such as EqNl o: ^ rramPles,80-997a)' :1:- ::{)m aziridine-2-carboxylicestctr o: I:rtcrestingly,the regioselectivityfc l.i:::;ri the metal halide to NaI (wi6

tt. 24h

ar /f\

LOPiv

96"/"

Ethers.3 Benzylic and allylic halides undergo alcoholysis to give alkyl ethers. Directed aldol reaction.a Unsymmetrical y-diketones are cyclized via the masnesiumchelates.

NHCOOET / M€OH; Mg(OMe)2

COOMe

Y

+

I

Br

NaOH / H2O

- 100./. .'lli ltributylstannane

on a-alkoxl

'Xu, Y.-C.,Bizuneh, A., Walker,C. JoC 61,9086(1996). txu. Y.-C..Bizuneh, A., Walker,C. TL37,455(1996). rl-in.J.-M..Li, H.-H.,Zhou,A.-M. TL37,5159(1996). *Cadtnun, M.L.F.,Crombie,L., Freeman,S.,Mistry,J. ICS(PI) 1397(1995).

9H n " - / "rr . r.Z \ ,lA i

\ - ./,,.

OBn

98% (ds >50 : 1)

-200 ; 18, 228 Magnesium monoperoxyphthalate (MMPP). 14, 197; 16, 199 from cyclic ketones using The preparation of lactones Baeyer-Viltiger oridation. presence of bentonite clay MMPP as reagent is mediated by acetonitrile,l as well as in the

208

Manganese-lead(Il)chloride-trimethylsilylchloride

(6 examples, 65-957o),2 although other solvent systems, such as aqueous DMF (for the synthesisof phthalides from benzocyclobutenones)'3have been employed'

t

, OMe l

n

aY"

Y

OMe

("Y'cosH vcoo)rtr,tg DMF - H2O

OMe

4oo, 0.5 h

.q 2 N+

,1, +

I

\-\O

,\"u^.,

730/"

2,S-Disubstituted furans give the di2,5-Dimethory-2,5-dihydrofurans.a methoxylated products on treatment at room temperature with MMPP in methanol (5 examples, 83-957o). The original substituentsin 2,5-positions are preserved' Sulfuxides,s Bentonite assists the MMPP oxidation of sulfides (15 examples. 68-967o). 2,2-Disubstinted f,y-unsaturated nitriles.o After deconjugative alkylation of enal N,N-dimethylhydrazones,MMPP oxidation (MeOH, 0") furnishes the nitriles' rHiruno,M., Yakabe,S.,Satoh,A., Clark,J'H.,Morimoto,T. SC26'4591(1996)' 2Hi.uno, M., Ueno,Y., Morimoto,T. SC25,3765(1995). 3Horoyu, Y., Suzuki,K. SL635(1995). T., Kuriyama, aD'Annibale, A., Scettri,A. TL36,4659(1995). sHi.uno.M., Ueno,Y., Morimoto,T. SC25,3125(1995). 6Mino,T.. Yamashita, M. JOC 61,1159(1996).

Magnesium perchlorate. 18, 228 In the presenceof Mg(clo)r, the admixture of an allylic alcohol and Allyl ethers.t another alcohol prone to ionize results in the formation of the mixed allyl ether. 'De Mico,A., Margarita, G. TL36,2679(1995). R.,Piancatelli,

Manganese-lead(Il) chloride-trimethylsilyl chloride. Manganeseis activated by a catalytic amount of PbCl, and MerSiCl by Altylation.r way of removing the tightly bound metal oxide that coats the surface.The system is useful for allylation of carbonyl compounds by allyl halides. A three-component condensation: Tandem reactions initialed by conjugale addilian. of alkyl iodides, electron-deficient olefins, and carbonyl compounds is an expedient synthetic procedure for skeletal construction. Exposure of allyl or propargyl acrylatesand alkyl iodides to the Mn-PbClr-MerSiCl system gives 1,6-unsaturatedor allenic acids. respectively, through a conjugate addition and Ireland-claisen reaction sequence'3

Takai, K., Ueda, T., Hayashi, T., Moriu alc. I tT"kui, K., Ueda, T., Ikeda, N., Moriwake. T . Trkai, K., Ueda, T., Kaihara, H., Sunamr. \' -

\tanganese(Ill)acetate.13, 17l: l.l. 19 SP Alkylation of malonateeskn. -.\)mologous diestersor lactonesin tlrefrs -:action2involvingsimultaneous addrtrc .r ntheticpotentials.

\-^.t-

\AO 4^"u''"

OMe

N

l o H

/v-1,,)

M%SiCl DMF- THF 2 5 0 , 0 . 5h

o

f.

C

I

Mn - Pbct2

:-a'::t'cooH I

M % S i C' lN M I D M F .T H F 400, t h

I --c=r'cu*t t 86"/"

73"/"

di.[\ . ^.lrtuted furans give (5 r.- :'r:rture with MMPP in methanol 11- < :,'.itionsarepreserved' rrJation of sulfides (15 exampler lPi the

'

'rilc'r deconjugativealkylation of enal

lc i: r.-,

r furnishesthe nitriles' ' r(- 26.4591(1996).

'Takai,K., Ueda,T., Hayashi'T., Moriwake,T'TL37'7049 (1996)' (1996)' -f^f.^i, f., Ueda,T.' Ikeda,N., Moriwake,T ' JOC 61^'7990 tf*r, f., Ueda,T., Kaihara,H', Sunami,Y', Moriwake'T' JoC 6l' 8728(1996)'

Manganese(Ill)acetate. 13,l7l;14,197-199;16'200:17'l'75-176;18'229-230 either Special procedures can be applied to form Alkylationofmalanateesters' reaction with olefins'l An intramolecular homologousdiestersor lactonesin the free-radical bond and carboxylation of the latter has a triple to addition reaction2involving simultaneous synthetic Potentials. HOOC\

tl -

COOMe

\,,^-- 99o/oal

rGotteland,J.-P.,Halazy,S. S,931 (1995)' 'A;J;";, c.1., spetr"rit, n., Norton' J'R', Meyers' A'l rL36' 1613 (1995)

'Morruy,R.W.,Iyanar,K., Chen,J.,Wearing.I 1 :Mu.ray,R.W.,Iyanar,K., Chen,J.,Wearing. I1 lMurruy,R.W.,Iyanar,K', Chen,J.,Wearing.J 1 tzhu,Z.,Espenson, J.H.JACS118,9901t 1996 5zhu,Z.,Espenson, I.H. JOCffi,1728(199:' oAbu-Oma., OM 15.-15J M.M.,Espenson,J.H.

Methyltrioxorhenium(VlD-urea-h.r-drq Allylic alcohols un Epoxidatinn."' but contrar] t( ofperacid, analogousto that

Methyttrioxorhenium(Vll)-urea-hydrogen 3Quadrelli, P., lnv emizzi, A.G., Caramella, P. TL 37, 1909 ( 1996). aHay, A.M., Ken, W.J., Kirk, G.G., Middlemiss,D. OM 14,4986 (1995).

....-SnMeg

Methyltrioxorhmium(Vll)(MTO).17,192-193 by Alkylations.' The O-atkylationof an alcoholby anotheralcoholis catalyzed

55""

\ :rrrrma. M., Watanabe,T., Yokoyama"

)

peroxide

MTO, and thus, both symmetrical and unsymmetrical ethers are readily prepared. Amines are also alkylated by alcohols. the Epoxides and aziridines.2 The rhenium carbenoid generated from decomposition of ethyl diazoacetateundergoescycloaddition with aromatic aldimines and with carbonyl compounds. The yields of the ethyl 3-arylaziridine-2-carboxylates are excellent.

Ur,: . 1,'phenols involves lithiation, and H I i r'\amPles,'l5-80Vo). .::nvatives without a metal catalyst. fi\

'

s0% O=N-COR from nitrile oxides is )c. .: - rrflr temperature.The reactive acyl r. 'lc,': , : svnthesis of cyclopentenones lF.:- :r!' ligand is attached to the dicobalt r\.

hi

tZho,Z,., E*p"n.on,J.H.JOC61,324(1996). 2zhr,Z.,Espenson, J.H.JOC 60,?090(1995).

:'- .4.s.

hydrogen peroxide. Methyltrioxorhenium(Vll): carbonyl compounds are obtained from alcohols by of bonds.' c-H oxidation hydrocarbons are also oxidized: adamantane to Some aq.HrOr-MTO. oxidation with (887o), cjs-4a-decalol (907o), and trd,?s-decalin to to cis-decalin 1-adamantanol (207o). tr ans 4a-decalol -adamantanamine Oxidation of amines. Secondaryamines give nitrones,2whereas l -nitroadamantane, to nitroarenes.l and anilines are converted is converted to l Reactionsof ethyt diazoacetates.4 Diazo compounds form metal carbenoids,which can insert into o-H, S-H, and N-H bonds. with compounds containing a c=X bond (alkenes, carbonyl compounds, and imines), cycloaddition takes place to afford cyclopropanes,epoxides,and aziridines. (Note that R\ and ArCHO form ArCH=NR in the presenceof MTO_and Ptt P). a-Diketones.s Alkynes are oxidized to c-diketones at room temperature' 1,3-cycloalkanediones lose the central carbon to give cleavageof pdiketones.b diacids.

dT"1 \_J O ^-

,:t^-Fl.

Ll

z'-i.'\ Ph-< | t

Y-:'l/

O

H

75% (> 99'/. et

;,

- 1 6 i f , l - 1( 1 9 9 5 ) .

'Muouy,R.W.,Iyanar,K., Chen,J.,Wearing, J.T.TL36' 6415(1995). tMu.ruy,R.W.,Iyanar,K., Chen,J.,Wearing,J'T.JOC 6l' 8099(1996)' rMu.ruy,R.W.,Iyanar,K., Chen,J.,Wearing,J.T.TL37,805(1996). tzhu,Z.,Espenson, J.H.JACSf 18,9901(1996). 5zhu,Z.,Espenson, (1995). J.H.JOC 60,'1728 nAbu-Oma., OM 15,3543(1996). M.M.,Espenson,I.H.

peroxide. Methyltrioxorhenium(Vll)-urea-hydrogen epoxidation in athreo-selective manner undergo alcohols Allyli. Epoxidation.t'2 process' the VO(acac)r-mediated to peracid, but contrary analogousto that of

218

Methyl(trifluoromethyl)dioxirane

MeReO3

.)ji?t-.o ...1'

OH

^^

r-nnJ-b;o

\ ct:

Z>act oY\,/

>\.

-

t l t

o-o

l l . - - - - - - " _ cHp? o -fr .!

threo

Rro.-/!n

.Yang,D., Wong,M.-K.,Yip, Y.-C../OCO. lt$' -Curci, R.,D'Accolti,L., Dinoi,A., Fusco.C.. Ri: G.,Mello,R., Gonzalez-Nunez. !rl.E..C ..{sensio, -Asensio, G., Castellano, G., Mello, R., Gonzalez

Y b A--G-r v---1/Jerythro

\Iethyltriphenylphosphonium

Nilrones.r

The oxidation of secondaryamines to nitrones with this oxidant mixture shows about the same efficiency as aq.HrOr-MTO.

borohl-dril Reduction.' Theborohydridereagerr gresenceof ketones,conjugatedcarbonvl ccn

rAdam, W., Mitchell,C.M.ACIEE35,533(1996). 'Boehlow, T.R.,Spilling,C.D. TL37,2717(1996). 'Goti, A., Nannelli,L. TL37,6025(1996).

io alcohols.

Methyl triflate. Activation of imidazolides.t N-Acylimidazoles are further activated N'methylation, making them susceptibleto attack by hindered alcohols and amines.

\Iethyl triphenylphosphoranylacetate. Olefination of lactones.l At high r.rrq *ith Ph,P=CHCOOMe to give the merhll \tereoselectivity for this reaction is lo\I..

Firouazabadi, H., Adibi, M. SC 26,2429tlc)96,

by

tulibulTi, G., Chorer,N., Bigg, D.C.H.S 1286(tgg6).

Methyl donor.2 Thi, Wittig reagenr r phenols,acids,and phthalimide.

Methyl(trifluoromethyl)dioxirane. 15, 212; 16, 224; 18, 242 The reagentcan be preparedr in situ from 1,1,1-trifluoroacetoneand Oxone@. Epoxi.dation.' Fast reaction in homogeneous system for all kinds of alkenes are observed. a-Ketols,z

Molybdenum carbene complexes. 17. lqf- | Oleftn metathesis. Cross metathesrs 1 rZ)-a,p-unsaturated nitriles.2Furthermore. em

Acetonides undergo oxidative ring cleavage.

qx

x"t'

asymmetric allylboration provides funcdonah

o-o

cH2ct2

: Lakhrissi,M., Chapleur,Y . ACIEE 35,750r I $)6 r -Desmaele, D. TL 37, 1233(1996).

OH

o o ,1 5 m i n

Oxyfunctionalizntion of unactivated C-H bonds. 2,2,3,3-Tet"ramethylbutane affords a primary alkyl trifluoroacetate3in 99vo yieldwhen it is oxidized with Me(cF,)co, in the presence of (cF,co)ro in dichloromethane at 0o. Esters show a remarkable regioselectivity in their oxidation.a

\ /

\ ,

/

\r11 //-*= ---,

/

c

(1)

Molybdenumcarbenecomplexes 2lg

OH

,\

">(\

fi"Y'v o \_./

aY"'

o-o

.

cH2ct2 -20o, 48 h

fi"Y'vo

a("'

o2-'t'2

Yang,D., Wong, M.-K., Yip, y.-C. JOC 60,3887 0995). -Curci, R., D'Accolti, L., Dinoi, A., Fusco,C., Rosa,A. TL 37, I l5 (1996). .\sensio,G., Mello, R., Gonzalez-Nunez,M.E., Castellano,G., Corral, I. ACIEE 35,Zl"l (1996). '.{sensio, G., Castellano,G., Mello, R., Gonzalez-Nunez,M.E. JOC 61,55g (1996).

\lethyltriphenylphosphonium

,,neswith thisoxidantmixturc

borohydride. Reduction.' The borohydride reagent is highly selective, reducing ardehydesin the presenceof ketones'conjugatedcarbonylcompounds to allylic alcohols,and acid chlorides :o alcohols. Firouazabadi, H., Adibi, M. SC 26,2429(tggil.

Ilethyl triphenylphosphoranylacetate.

lta

,' turther activated .:J alcoholsand amines.

b

oleftnation of lactones.t At high temperaturesin a nonporar solvent, racronesreact nith PhrP=cHCooMe to give the methyl 2-oxacycloalkylideneacetates. However. the 'tereoselectivity for this reaction is low. Methyl donor.' This wittig reagent is able to donate a methyl group to amines, rhenols,acids,and phthalimide.

It U ' : .r.c'to[l€ and Oxone@. ' ri,r all kinds of alkenes !':.'

r

,1996\. .Lakhrissi,M., Chapleur,y. ACIEE 35,750 -Desmaele, D. TL 37, 1233(1996).

\tolybdenum carbene complexes. 17, 194_195: lg. 242_243 Olcftn metathesis. Cross metathesis permits a facile access to allylsilanesr and Z/-s,p-unsaturated nitriles.2Furthermore, employing an alkene metathesis in tandem with esymmetric allylboration provides functionalized alkenes.3

)-oH 39". I 1..1.-3-Tetramethylbutane t^,.' :: r\ oxidizedwith Me(CFr)CO. i:

Esters show a remarkablc

4' n,

N=Mo{CFs

{.'.\* cFs (1)

220

Molybdenumcarbenecomplexes

lMol

Y.,"".

Ph/\

p6'Vsiu".

DME 85To

["o]'

vt*

c8H1/\

"rttr)

CH2C12 CN 72Y"

There are severalimportant applications of the Mo-carbene complex (1) in the synthesis of natural products, illustrating the power of the ring-closing olefin metathesis. Thus, elegant synthesesof coronafacic acid,adactylol,s and fluvirucin6 have been reported.

o A-./\/t ( l

l

Vr-/ I

MeOOC

cooH coronafacic acid

COOMe

[Mor; N

-

\--\

-'

BU4NF

-r

) \-

/

I

l-z-siMet

7-AcO , QAc

,ol4 * "o"r,

|

/--2ct'

dactvlol -

)

ncg ,9Ac

I

t

-

\Iolybdenum hexacarbonyl.13. l 9l Cyclopentenones.' The Paus hasbeenextendedto thepreparatror

aH-{

85"/.

,

Crowe, W.E., Goldberg, D.R., Zhang. ZJ -Crowe, W.E., Goldberg,D.R. JACS I l?. 'Banett, A.G.M., Beall, J.C.,Gibson.\'G -Htjlder, S., Blechert,S. SL 505 (1996r 'Fr.irstner, A., Langemann, K. ,IOC 61. 8-r 'Xu,2., Johannes,C.W., Salman,S.S..Hc Huwe, C.M., Velder, J., Blechen, S. ACl/ 'Fujimura, O., Grubbs,R.H../ACS llt. :.1

l

\

--\

A9*r"o"r, "

l

i ' Y "i ' r '

HNJ

fluvirucin It is interesting that a Mo-carbene complex and a Ru-carbene complex can show different stereoselectivepatternsin ring-closing olefin metathesis.T An asymmetric version of olefin metathesisutilizes a Mo-carbene complex (2) with (R,R)-1,2-bis(Z-hydroxy-2,2-bistrifl uoromethyl)ethylcyclopentaneas a ligand.8

Alkynemetathesis. Substiturc Cross-alkyne couplingprovidesa rrr tu o svmmetricalalkvnes.3

r

OAc

OAc

Allylic substilutions. A ne* !r j ;atalystfor allylic substitution

Molybdenumhexacarbonyl

ph'

/ \ nv

221

'SiMe3

85"/"

cFs

,^ caHrz \) I CN

(2)

721"

- rrtrenecomplex (1) in the synthesis :.:.:-ilosing olefin metathesis.Thut )c '- -r rrucin6have been reported. l

o Ar'V\ ( t vY

l I

cooH

:Crowe,W.E.,Goldberg, D.R.,Zhang,Z.J.TL37,2ll7 (1996). -Crowe,W.E.,Goldberg,D.R.JACSll7, 5162(1995). 'Barrett, A.G.M.,Beall,J.C.,Gibson,V.G.,Giles,M.R.,Walker,G.L.P.CC2229(1996). 'Hdlder, S.sL 505(1996). S.,Blechert, 'F,.i.rtn"r, A., Langemann, K. JOC 61,8746(1996). "Xu, A.H. "/ACS118,10926(1996). 2., Johannes, C.W.,Salman, S.S.,Hoveyda, Huwe,C.M., Velder,J.,Blechert,S.ACIEE35,23'76(1996). 'Fujimura, O., Grubbs,R.H.,IACSL18,2499(1996). llolybdenum hexacarbonyl . 13, 194 - 195 ; 15, 2 12-213 ; 16, 225-226; 18, 243-244 Cyclopentenones.' The Pauson-Khand reaction catalyzed by Mo(COI in DMSO has been extendedto the preparation ofo-methylenecyclopentenones.

coronatacic acid Mo(CO)6

n/z

-

/_rw

dactYlol

lz=-siuet

a-.-", l F o

(

DMSO - PhMe

*\

1000, 3 h

SiMe3 68%

Aco , gAc ^t / |

'

/)3NHcocF3 l

t l

Alkyne metathesis. Substituted tolanes are formed from alkyl aryl acetylenes.2 Cross-alkyne coupling provides a new route to unsymmetrical disubstituted alkynes from two svmmetrical alkvnes.3

^

I

o 2",,, -',J

t

l

Ph Mo(CO)6

* f luvirucin a:.J .i Ru-carbene comPlex can shos e:::::rctathesis.T Dl:,':. a Mo-carbene comPlex (2) with as a ligand.8 [\.-'., ir)pentane

[*"

\rlronc

ill

lll I

Ph

4-CtC6H4OH PhMe,1100

rll-"* Ph

74"/" Allylic substitutions. A new Mo complex (l) derived from Mo(CO). is an active catalvst for allvlic substitutioni

Montmorillonit€ clays

OAc

-\ t r l =A-\ Mo(CO)6

IBnNEt3]+Cl-. ..-.----------------*

OMe ,-.t

[(OC)5MoOTf]tOTf-

AgOTf (1)

t r l

;;;* DME- CH2C|2 rt,4h

H

937.

lKent, J.L., Wan, H., Brummond, K.M. Il 36, 2407 (1995). 2Kaneta, N., Hirai, T., Mori, M. CL627 (1995). 3Kun"tu, N., Hikichi, K., Asaka,S.-L, Uemura,N., Mori, M. CL 1055 (1995). aDvorakova, H., Dvorak, D., Srogl, J., Kocovsky, P. TL36,6351 (1995).

Molybdenyl acetylacetonate. 18, 244 The deprotection of acetals is performed in high yields (9 Deacetalimtion.r examples,7O-95Vo). MoOr(acac), catalyzes the oxidation of alcohols by sulfoxides. Oxidation.' Aldehydes are obtained from primaryalcohols. The conversion of propargylic alcohols to Meyer-schuster rearrangement.' conjugated carbonyl compounds is effected by heating with MoQ(acac), and BurS=O in o-dichlorobenzeneat 100o.

Mo02(acac)2

/\f

\Iontmorillonite clays,metal iondoped. Methylthiolationof thiophenes.' \\pcrn morilloniteK 10,thiopheneundergoes

cno

Bu2S=O 1,2-Ct2C6H4 1000, 5 h

tKuntu-, M.L., Swapna,V., Santhi,P.L. SC 25,2529(1995). 'Lorber,C.Y.,Pauls,I., Osborn,J.A. BSCF133,755(1996) 3l-orber. C.Y..Osborn,J.A.TL37,853(1996).

Montmorillonite clays. 15, 213-214; 18 Acid-catalyzed organic reactions by using clays continue to attract attention, and manl reports on acetalization have appeared.The formation of C-glycosides by the reaction of glycals with enol silyl ethers,acetates,and allylsilanesis efficient (53-977o)l Catalyzed reactions that are further assistedby microwave heating include aldolizatiori and Beckmann rearrangement.3 lToshima,K., Miyamoto,N., Matsuo,G., Nakata,M., Matsumura,S. CC 1379(1996). 2Abdulluh-Elayoubi,S.,Texier-Boullet,F. ./CR(S)208 (1995). 3Bosch, E.,Loupy,A., Langa,F. SZ 1259(1995). A.I.,de la Cruz,P.,Diez-Barra,

a \/

s

+

MeS-SMe

llctr

z

Aromatic nitration usrng Nitration.' :npregnated acidic montmorillonite clal . Potassiumferrate(\'l r sl Oxidations. 'i alcohols to carbonyl compounds. of

Another method for oridiz:n -'ompounds.3 -lays.a

Thehydroesterificr Homologation rn alcohol under pressurealso works * hcrl

Clark,P.D.,Mesher,S.T.E.,Primak,A. PSSI lr 'Gigante, \tl A.O.,Marcelo-Cuno. B., Prazeres, Delaude,L.. Laszlo,P. JOC 61,6360( I 996t 'le OliveiraFilho,A.P.,Moreira,B.G..\lcr-an,I 'i-ee. C.W.,Alper,H. JOC60,250(1995r

Montmorillonit€ clays, metal ion-doped

OAc t t -:A--\ /

r--:-'

OMe

l

MeOH DME- CH2C|2 rt,4h

,l-.. t t

H

Montmorilloniteclays,metal ion-doped.15, 101,178-179; 18,244-245 Metfulthiolationofthiophenes.' When autoclaved with ZnClr-doped-montpermethylthiolation. morilloniteK 10,thiopheneundergoes

l

93%

O

MontmorilloniteK + + Mes-sMe

l0

Z n C l 2 ,1 5 O o , 5 h

MeS

auloctave 50%

\l cr 1055(1995). , \1 P . .16.615l (1995).

(.: .,-.tals is performed in high yields (9 li:

,rrdation of alcohols by sulfoxides.

Nilration." Aromatic nitration using fuming nitric acid is catalyzed by Cu(NO.)rrmpregnatedacidic montmorillonite clay. Potassiumfenate(Vl) supportedon clay has been used in the oxidation Oxidations. of alcohols to carbonyl compounds, of thiols to disulfides, and of organonitrogen ;ompounds.3Another method for oxidizing alcohols involves acyl nitrates absorbedin ; lays.a

)i.

tc - ::\!'rsion of propargylic alcohols !o b. -:.,rrns rvith MoQ(acac), and BurS=O in

^('-cno

^r:

s-

-ontinue to attract attention, and man;rr,,n of C-glycosidesby the reactionof 1 1 , . :rcr is efficient (53-97Vo)l rriro\r'ave heating include aldolizatiori N t -

:.unrura, S. CC 1379(1996). a5r

::rr. F. SL 1259(1995).

Homologation The hydroesterification of alkenes using Pd(OAc)r, CO, Ph.P, and .rn alcohol under pressurealso works when the clay-supportedcatalyst is used.5 Clark,P.D.,Mesher,S.T.E.,Primak,A. PSS114,99 (1996). -Gigante,B., Prazeres, A.O., Marcelo-Curto, M.J.,Cornelis,A., Laszlo,P. JOC 60,3445(1995). 'Delaude. L.. Laszlo.P. JOC 6I.6360(1996). 'deOliveiraFilho,A.P.,Moreira,B.G.,Moran,P.J.S.,Rodrigues,J.A.R. TL37,5029(1996). 'Lee, C.W.,Alper,H. JOC 60,25O(lgg5).

Bricout, H., Carpentier, J.-F., Mortreux. A C 'Bricout, H., Carpentier, J.-F., Mortreur. A 1l Trost, B.M., Spagnol,M.D. JCS(P// 208-rr i'

Nickel. 12, 355:,13, 197; 14, 213; 18, 246 Free radicals are generatedfrom trichloroacetamideson reaction with f-Iactams.' nickel powder-acetic acid. One report describesfour examples of intramolecular additioo of the radical, leading to p-lactams in24-65Vo.

r-sPh cl -"' "' I ^,-a 2:'. u r

cr

Ni - HOAo

\ /

z2*NBn

o'

\ickel(ID acetylacetonate.17, 201: lt. Metallated sul Homocouplings.' elkenesunder Ni catalysis. Cross-couplings, The enynes arc

Tlre Ni(acac)r-catalyzedcross-coupling useful becausemany functionalities are t .'an intervene in this coupling thereb) ctl

ll

^,--s "'

/:PrOH A

)-i,"

znt'

o'

Qf"oo''

50"/"

Cleavageof perlluoro epoxides.z In combination with iodine, nickel powder promotes the cleavage (C-O and C-C) to form acyl fluorides and gemdiiodoperfluoroalkanes. 'Quiclet-Sire, B., Saunier, J.-8.,7,ard, S.Z.TL37, 1397(1996). 2Y ang,Z.-Y../ACSI 18,8140( 1996).

Et2Zn - t*e

,,")"( Nickel, Raney-sodium hypophosphite. Chiral alcohols.' The reagent system in a buffered medium (pH 5.2) accomplishes the desulfurization of thioethers without causing racemization of a secondary alcohol (l l examples,54-897o). 'Nirhid", K., Shigeta, Y., Obata,K., Inoue,T., Node,M. TL37,22'll (1996\.

tta THF .T'I

CuCN- 2 LO

,r=F-

Efficient coupling of benzylic chlon speciesformed by the reduction of \it r equivalents of Ph,P.sBy contrast. Pdr0r particularly in the cases of hindered t synthesisof coenzymeQn.

Nickel(0)-phosphine complexes. Displacements.' Nickel complexes can serve as an alternative to the Pd catalyss. e.g., in the synthesis of allylaminest and c-allylmalonic esters.2A report on the latter reaction states that bis(aminophosphine) ligands are more efficient than dppb and other usual phosphines. l,4-Dienes.3

Coupling of allylamines with alkenylboronic acids with (Ph.P)rNi in benzeneleadsto l,4-dienes.

c,onlB(oH)'*

E'2N/V

(Ph3P)4Ni

PhH ^

MeO

?Y

'-,,,\.'tt-"'

",*v",arn/\,\

MeO

Michael I Conjugate additions. alkenylboranesTas donors proceed in t

Nickel(Il)

acetylacetonate

'B.icout,H., Carpentier, J.-F.,Mortreux,A. CC 1863(1995). rBricout,H., Carpentier, J.-F.,Mortreux,A.TL37' 6105(1996). rTrost,B.M.,Spagnol, 2083(1995). M.D..ICS(P1)

t::: l a\

:tl()roacetamideson reaction witb .,r'nplesof intramolecular additim

cr

Nickel(Il) acetylacetonate. 17,201; 18, 247 -248 Metallated sulfones undergo coupling to give symmetrical Homocouplings.l alkenesunder Ni catalysis. Cross-couplings. The enynes are formed from allyl halides and alkynylstannanes.' The Ni(acac)r-catalyzed cross-coupling3of alkyl iodides and dialkylzincs is particularly useful becausemany functionalities are tolerated. An intramolecular addition to an alkene can interyene in this coupling thereby creating functionalized cyclic compoundsl

ll

-^ --1"\ .l_ilen

(e"oo* (-.

3

r

50% B:

,"'[\Moo.], Ni(acach THF - NMP

': s ith iodine, nickel powdcr :nr acyl fluorides and gem-

C:loo.

-780 -> -350

78%

Et2Zn - Ni(acac)2

,,")"(

C u C N - 2 L i C/ lT H F ;

\ er-rf-cooet fl:'-'.: nredium(pH 5.2) accomplishes r'- . .rrr()nof a secondaryalcohol (l I

L-r-rt-l(1996).

Efficient coupling of benzylic chlorides with alkenylaluminums is catalyzed by Ni(0) speciesformed by the reduction of Ni(acac), in THF with l-BurAlH in the presenceof four equivalents of Ph.P.5By contrast, Pd(0) catalysts are much inferior in this cross coupling, particularly in the cases of hindered benzylic chlorides, such as those required in the synthesisof coenzYmeQn.

l |a

r

a alternative to the Pd catalysts. A report on the laner - c'StcrS.2 :r' etficient than dppb and other

MeO

r"r^ (VAf\H ",*

l\:: .lirrronic acids with (Ph.P)"Ni in MeO

P..'

c*alN

t 85%

Ni(o)-cat > G+

""/-\^^G" 47"/o

Michael additions involving cyclic p-keto esterso and Conjugate additions. proceed in the presence of Ni(acac)r. By using a mixture of alkenylboranesTas donors

226

Nickelbromide

dimethylzinc, a l-alkyne, chlorotrimethylsilane, and phrp, in addition to Ni(acac)r, rhe introduction of a 2,2-disubstitutedalkenyl group to enones8is accomplishedin one step (5 examples,58-89Vo).

+

C6H13----

-4

i l )

o lt

/ a 1

Ni(acac)2 - PPh3

Me2Zn- MqSiCl

C6n13-^VV

T H F , 2 5 0 ,2 h ;

89./.

HCt- H2O

The regioselectivity in the conjugateaddition of alkyl aluminums and methyltitanium ate complexes to androsta-1,4-diene-3,l7-dioneis reversedin the presenceof Ni(acac)^.e The cycloaddition betweendiene, and unactivatednisystems [4+2]Cycloaddition.r0 often proceeds at room temperature in the presence of transition metal catalysts. The catalytic system [Ni(acac), and EtrAloEt] for such a stereoselectiveprocesscan be replaced by Ni(cod)r, as applied to a synthesisof a precursor to A-aromatic steroids.

Condon-Gueugnot,S., Leonel, E., Nedelec. J -\' . I 'Durandetti. M., Nedelec, J.-Y., Perichon. I. JO( a r)livero, S., Dunach, E. CC 249'l (1995',.

-. 15,2 I 6-l I \ickel carbonyl.13, 198-1991 Cyclnpentenones. The cyclocarbonl rrlyfunctionalproductsin onestep.Stereos

o

tt\

\

ToFS=O

ry (o

\ickel chloride dihydrate. Hydrated NiCl. and Hyd.rogenation.' for alkenesland alkFr :.rrm a reducingagent

Ni(cod)2 (,-CaHF6)Ol3P

MeOOMOM

B = SiMea

90% tcui, Y., Julia, M., Verpeaux,J.-N. aSCF 133, g05 (1996). 'Cui, D.-M., Hashimoto,N., Ikeda,S.-I., Sato,Y. JOC 60,5752 (1995). 'Devasagayaraj, A., Studemann,T., Knochel, p. ACIEE 34,2'123 (lgg5). -Vaupel, A., Knochel, P. JOC 61,5743 (1996). -Lipshutz, B.H., Bulow, G., Lowe, R.F., Stevens,K.L. "/ACS11g,5512 (1996). oRao. H.S.P.Reddy.K.S., Jeyalakshmi,K. IJC(B) 34B,809 (1995). 'Yanagi. T.. Sasaki,H., Suzuki,A., Miyaura, N. SC 26, 2503 (1996). Slk"du, S., Yamamoro,H., Kondo, K., Sato,y. OM 14,5015 (1995). J., Neh, H., Nickisch, K. CB l2g,963 (1996). .eWestermann, r0Wender, P.A., Smith, T.E. JOC 60,2962 (lgg5\.

Nickel bromide. NiBr,

has been empl

Villar, J.M., Delgado,A., Llebaria,A.. Moreto. J I

OMOM

Arylations,

Note that (bipy)rNi(BFo),

- leavage of allyl ethers (Mg anode).1

is a useful catalyst for the electrochemical

arylation of activated

alkenes.r cross coupling of aryl halides with activated alkyl halides (e.g., u-halo ketones)2 occurs under similar conditions.

\lonso,F., Yus,M. 7L 37, 6925(19961. tAlonso.F.,Yus,M. TL38, 149(199'7).

\ickel chloride-phosphine complexe l{. The tPh.Pl Transfer hydrogenation.' .-arbonyl compounds by isopropanol in Or p Nucleo Addition to activated imines.rhe presenceof (Ph.P)rNiClr. Coupl Coupling with organoborates. .ulfonates,aas well as allylic carbonates.tI

q. )-q o.r\A"oo=,

+

Q ; r

Nickel chloride-phosphine complexes

Ph.P. in addition to Ni(acac)r, the ,nes'is accomplishedin one step(5

o lt

),_-'l . t t , i : :

i 1 1 C5H13-^\,,^J

:-

2:

89"h

has been employed

Note that (bipy)rNi(BF/,

as the catalyst for the electrochemical

cleavage of allyl ethers 1Mg anode).3 rCondon-Gueugnot,S., lronel,8., Nedelec, J.-Y., Perichon, I' JOC 60"1684 (1995)' :Durandetti, M., Nedelec, J.-Y., Perichon, I. JOC 61,1748 (1996)' rolive.o, S., Dunach, E. CC 2497 (1995).

Nickelcarbonyl.13, I 98- I 99; 15,216-217; 18' 249 of allyl halidesand alkynesfurnishes cyclopentenones. The cyclocarbonylation is alsoobserved' polyfunctionalproductsin onestep.Stereoselectivity

or .: r : I eluminums and methyltitanium ate of Ni(acac)r.e 31:'.:J rn the presence io*'.' :cn dienesand unactivatedn-systems

'b

\,

!--r'-.. rrf transition metal catalysts.The :h .: .:.rr'oselectiveprocesscan be replaced \ ' \-aromatic steroids.

Ni(co)4 KOAC/ M6OH

\ + Tol-S=O

63"/"

,Villar,

( 1996). J.M., Delgado,A., Llebaria,A., Moreto, J. M., Molins, 8., Miravitlles, C. T 52, 10525

\ickel chloride dihydrate. Hydrated NiCl, and Li with a catalytic amount of naphthalene Hydrogenationl iorm a reducing agent for alkenesr and alkynes.2

h

.\lonso,F., Yus,M. IL 37, 6925(1996):Alonso.F., Yus,M. TL38, 149(1997). 14-

('rrt '-,,, tnrtr. t : . u : - : . 1( 1 9 9 5 ) , . I 1 8 .5 5 1 2( 1 9 9 6 ) . .. .q95).

ts . b ll

_. i l996). . < tqp5).

Nickel chloride-phosphine complexes. 14, 1251'15, 122; 16, 124; 18' 250 The (P\P)2NiCl2 complex catalyzes the reduction of TronsJer hydrogenotionl carbonyl compounds by isopropanol in the presenceof NaOH' in Addition to activated imines.z Nucleophiles such asmalonateestersadd to imines the presenceof (Ph,P)rNiClr. Coupling Coupling with organoiorates. 'ulfonates,aas well as allylic carbonates.5'6

q I rf : -.r'strochemicalarylation of activated rr., :,r rlkvl halides(e.g.,cr-haloketones):

)-or

o.,,2.7t"oo.,

+

G

partners can be aryl

halides3 and

M e L i, B ( O M e h ;

+

(dppf)NiC12

HO

cooEr

22E

Nitric acid

Alkenes.T vic-Dibromides undergo debromination with EtMgBr-(dppe)NiCl, in THF at 0'. Alkynes are obtained from dibromoalkenes. Alkylidenationofdithioacetak.s With (dppe)NiCl, gem-bimetallic reagenc (RCH[MgBr]ZnBr) react with dithioaceralsto form trisubstituted alkenes. rlyer, S.,Varghese, J.P.CC 465(lgg5). 'Shida, N., Kubota,Y., Fukui,H., Asao,N., Kadota,L, Yamamoto,y. TL36,5023 (lgg5). 3suito,S., Sakai,M., Miyaura,N. IZ 37, 2993(1996). -Kobayashi, Y., Mizojiri,R. TL37,8531(1996). 'Mizojiri, R., Kobayashi,Y. JCS(Pl)2073 (1995). oKobayashi, Y., Mizojiri,R.,Ikeda,E. JOC 61,5391(1996) 'Malanga, C.,Aronica,L.A., Lardicci,L. TL36,9189(1995). 6Tseng, H.-R.,Luh,T.-Y. OM 15,3Wg(tgg6').

Niobium(V) chloride. Homologatianl o-Trimethylstannylmethyl-B-ketoesters are converted to ^lketoesters in the presence of NbCI' presumably via cyclopropanol intermediates (6 examples, 34-88Vo). The tributylstannylmethyl analoguesgive inferiorresults.

\itric

oxide. Nitration of alkerrs Nitrations.l performed with NO in 1,2-dichloroethancI .ue dehydratedby heating with acidic aluru Anisole and its derivatives are nitrated u Reductive deamination.3 Aromarr.'1 compoundswith NO in THF under argon

Hata,E., Yamada,T., Mukaiyama,T. ECSJal. -Mizuno,K., Tamai,T., Hashida,L. Otsu1.\' . lt 'ltoh, K., Ohsaua-A f Y., Nagata, T., Matsuya,

\itridomanganese(Y) salen complere The complexes(lr art Aminatian.' enol ethers, providing cl-amino ketorrs T'

f,gentsother than porphyrin derivatir.es.Us of tCF.CO),O to acylatethe amino group

F

o ,\ .cooEt Ph, Y I -snMe3

'''R

o Nbcts/ cH2ct2 -fio

:N

pnYcooet 51"/"

Y

/:\

\.\:____i/-o

N

(1 Ar -78" in ether, the Nbclr-catalyzed cycloaddition between cyclopentadiene and crotonaldehyde is complete in I h. Interestingly, the endo-to-exoratio is 1:9. Dicls-Alderreactions.z

rYamamoto, M., Nakazawa, M., Kishikawa,K., Kohmoto,S CC 2353(1996\. 'Howarth, J.,Gillespie, K. TL37,6011(1996).

Nitric acid. 18, 251-252 Nitrations. Sulfuric acid on silica gel is an inexpensive catalyst for nitration.l For nitration of strongly deactivated arenes, the mixture of HNo,/2cF,So,H-B(orf), is effective.2 oxidafion of sulfides.3 The oxidation to sulfoxides is accomplished by HNo., catalyzedby FeBr, and (FeBr)r(dmso)r. rRiego, J.-M.,Sedin,2.,Zaldivar,J.M., Marziano, N.C.,Tortato,C. TL37,513(1996). "Olah, G.A., Orlinkov,A., Oxyzoglou,A.B., Prakash,G.K.S.JOC60, ':.348(lggs,t. 3sua.er, A.R.,Rossi,L.I., Martin,S.E.ZL 36, l20l (1995).

'Du Bois,J.,Hong,J.,Carreira, 8.M.. Da1. \t \r

Nitrobenzene. a-Substituted lactic acids.t Ar hrgfr ketonesare transformed into lactic acids sr

Ph. ,\ V Y i

o

l

:

t

'srinivasan,P.S.,Mahesh,R., Rao, G.V.. Kalrr

6

Nitrobenzene 229 al:

:

5

e \.(

\\ irh EtMgBr-(dppe)NiCl, '1..

in

gem-bimetallic reagents

"t. - '.

trtutedalkenes.

ti-

.\" TL36,5023(1995).

It{itric oxide. Nitratians.t Nitration of alkenes (e.g., styrene to B-nitrostyrene) is readily performed with NO in 1,2-dichloroethaneat room temperature.Nitro alcohol side products are dehydratedby heating with acidic alumina. Anisole and its derivative^sare nitrated using an NO-O2 system.2 Reductive deamination,r Aromatic amines are converted to deaminated aromatic compoundswith NO in THF under argon. The yields range from trace amounts to 92Vo. rHata, E., Yamada,T., Mukaiyama,T. BCS"I6E, 3629(lgg5). -Mizuno, K., Tamai,T., Hashida,I., Otsuji,Y., Inoue,H. JCR(S)284(1995). 'ltoh, T., Matsuya, Y., Nagata, K., Ohsawa, A. TL37,4165(1996).

l:'l r.tcrs are cOnverted to tt:. . r;lspl6panol intermediates(6 tu.. rr\ e inferior results.

Itlitridomanganese(V) salen complexes. Amination.' The complexes (1) are very effective for aminating electron-rich silyl enol ethers, providing s-amino ketones. These are the first members of nitrogen transfer agentsother than porphyrin derivatives. Usually, the reaction is conducted in the presence of {CF,COlrO to acylatethe amino group.

R R

+-{-

c ='

v

N.

CooEt

,N Mn

dilr'c

5't%

N

(1) hr' \hCI.-catalyzed cycloaddition rcr: ii!' in I h. Interestingly, the

( , : i : . 1( 1 9 9 6 ) .

'Du

R=H'Me

Bois,J.,Hong,J.,Carreira, E.M.,Day,M.W. ./ACS118,915(1996).

Nitrobenzene. a-Substituted lactic acids.l At high temperaturesunder basic conditions (NaOH), ketonesare transformed into lactic acids with PhNO, serving as an oxidant.

r:.:r.r\e catalystfor nitration.l For I : I{\O.,/2CF.SO,H*B(OTf), is Ph. ,.r

\,/ Y /

)\:i!.

is accomplishedby HNO,

ll o

PhNO2 NaOH 1600

\ ,OH P h X O H

"Y

o 480/0

rt, 37,513(1996). r 89 9 5 ) . J , " H t . 7 - 1 4( 1

'srinivasan, P.S.,Mahesh,R., Rao, G.V., Kalyanam,N. SC26, 216l (1996).

Nitryl iodide

4-Nitrobenzenesulfonyl azide. a-Diozocarbonllcompounds. B-Diketones and p-ketoesters are converted to a-diazo ketonesr and diazo esters,2respectively, on reaction with the sulfonyl azide in CH2Cl2at room temperature,using DBU as a base. rTaber, D.F.,Gleave, D.M.,Hen,R.J.,Moody,K., Hennessy, M.I. JOC 60,22g3(lgg5). 'Taber, D.F.,You,K., Song,Y. JOC 60,1093(1995).

Nitrogen dioxide. 15, 219; 18, 252-253 Deacetalization and dethioacetalization.

Cyclic acetals of ketones are cleaved by Nor in the presence of silica gel (5 examples, 88-l00zo).r carbonyl compounds are similarly recovered from dithioacetals2by treatment with "nitrogen oxides," which are preparedfrom arsenousoxide with concentratedHNOI. selenoxides. preparation.3

Autoxidation in the presence of No,

is a mild method for the

Organoantimonyreagents.17,2M: lt. l-< Knoevenagel reactions.t Alkllidcrra dibromomalonicestersand carbonvlconq 70-95%). examples, ;Davis, A.P., Bhattarai,K.M. I51, 8033 ( l9)i,

Organocerium reagents.13,206:14. : l Reaction with carbonyl compourrds.

--:

l

behavesnormally as a nucleophile. Lithium a convertedto the correspondingcerium specr.

rNishiguchi, T., Ohosima, T., Nishida,A., Fujisaki,S. CC I l2l (1995). 'Mehta, G.,Uma,R. TL37,l8g7 (1996). rBosch. E.,Kochi,J.K. JCS(Pt) 2731( t996).

studied.2

Nitronium tetrafluoroborate, 14, 215 Nitration.t Allylsilanes undergo desilylative nitration with transposition. rBeresis, R.T.,Masse,C.E.,Panek, J.SJOC60,ii 14(gg5t.

4-Nitropyridine N-oxide. a-siloxy aldehydes.t cr-Trimethylsilyl epoxides are converted to the siloxy aldehydeswith 4-nitropyridine N-oxide with TMS-OTf as a catalyst.

LDA;CeCls

o'-

-.-H

Wn-,," o

plminoalcohols.r

Alkaneimidolk-cr

and RLi/CeClr. On quenching with carbonr I

o

t\ib3sioTf/ CH2C|2 ozN{

' t--\+ N-o

o*")"''oh OS|M€3

%*O, BuLi;

a 0.5h

NC v9vl3

THF

'Raubo, P.,Wicha,J. TL35,3387(1994).

Nitryl iodide. Nitration. Cyclic conjugated alkenes give nitroalkenes on reaction with nitryl iodide, which is preparedin situ from iodine and KNO, (18-crown-6). rGhosh, D., Nichols,D.E.S 195(1996).

-780, 0.5 h

'Tokuya.a,

t _

lL (_ 7\ B^u ,

/a

H., Isaka, M., Nakamura E. SC L rt

:

Bul"""

CI

Dioxolanes derived from o,p;y,6-dienals can react with organocopperreagentsat both rhe s- and y-position. Interestingly, chiral dioxolanes of such a substitution panern give optically active products,rr due to remote asymmetric induction.

. - : c r s> 1 2: 1 )

1c hc'en obtained from | : . r , ,s t e p s ) . 3

the

=

..__s

^ Rh K'ot ) ' o sFn

cooEr -:.. h.. .'railableorganozincshave hzr.: molecules. For example. ln:I i.1l!'\ the preparation Of ?. .,r'r'uS€din the coupling with

t

f,.; !: r

3

$.:rdroxy silanes due to the ti i ::\ tor the reactionof methyl (r: lhe presenceor absenceof ir:.rtrcantwith the addedlrwis f ::r'rr vinYl sulfoxides with

v\cHo

H

Etao, -30o,30 min

+ (70 : 30)

Iithium reasentshas been unveiled.l3

Y\,^-o o

of

of RM / Et2O -1000, 2 h

--t

\rro. o 2'M=Li 60%

. : \

\

V"v^,-o i l : o /'1

M=Cu 80%

.

:r' :rJ tellurides.o

/'. enf

Addition to C=X bonds. A preparation of Cr-symmetric di-s-phenethylamine is performed by the addition of MerCuLi to the benzal derivative of (S)-1-phenethylaminein rhepresenceof BF,.12 A remarkable contrast in stereoselectivityof the copper and Conjugate additions.

o+ TIPSO

P h c u- B F 3 ' o E t 2

'1

36

Novel organocupratesused in conjugate additions are 2-(trimethylgermyl)allylcopper(l) and the iMerS complexl,ra dilithium bis[2-trimethylstannyl)vinyl]cyanocuprate.r5 a-azoalkylcuprates.I6 Long-chained alkylphosphonates are formed by the addition of cuprate to a vinylphosphonate ester. The addition-trapping protocol gives rise to the less accessible branchedcompounds.lT

234

Organocopperreagents

Alkenyl triflones have unusualreactivities. A stereoselectivesynthesisl8oftrisubstituted alkenyl triflones involves the organocoppersand alkynyl triflones.

-npolung manier. It is important that. duru .rbstituents remain on the tin atom. Tlrrs .e.-ondarycyclohexyl groups has an advantag

Cu CF3SO2:Ph

+

'.llowed by acetylation and treatment \rrth i 'romide) in the presenceof CuCN effecrs a (

Vo \)

Et2o - 11 0 0

OAc (E:Z 12:1) 82o/"

,J. -SnCy3

C5H11'

Allenes are obtained from the 1,6-addition to sulfonyl enynes.reActually, acetylene itself is receptive to attack by silylcuprate reagents,giving rise to (Z)-alkenylsilanes after trapping with electrophiles.20

\r

Me2CuLi- Mq3sil

\

\r.Z'ggrp6

Et2O, -20o; 2N H2SO4

\ u.r A v s o 2Ph

3-Methory-2-acylmethylationof 2-cycloalkenols,zr Fused-ring cyclopropyl carbinols derived from 2-cycloalkenols undergo ring opening in methanol with Hg(II) salts; the ensuing intermediates are readily converted to the alkyl(methyl)mercury derivatives. O-Acylation followed by reaction with MerCuLi2 gives the functionalized cycloalkanols.

/-

(-f

OH I

OH

-l(}

Hg" / MeOH;

(t''n", 9,".or.

rc

cY = cyclohexyl

Danielmeier, K., Schierle, K., Steckhan,E. .\ClE/ 'Linderman' R'J" Chen' s' ZZ 36' 7'799(1995' 'Jefford, C.W., McNulty, J.,Lrt,Z.-H., Wang. J B '\'ettel, S., Vaupel, A., Knochel,P. fL 36. l0:-r , I 'Tsushima, K., Hirade, T., Hasegawa,H.. Murar. ! "Chieffi. A., Comasseto,J.V. SL 671 (1995t.

45"/.

OH

c{

MeCu; HglI.

RCOX

j uqcuLi v OH I

./\l:/R l t \ V...or"o Reductive umpolung of aldehydes.z2 A th.""-rtep reaction sequenceaccomplishes this transformation. Thus, the reaction of an aldehyde with tricyclohexylstannyllithium,

Hudrlik, P.F., Ma, D., Bhamidipati, R.S.. Hudrtfi '\agumo, S., Irie, S., Akita, H. CC 2001 ( 1995' '\tarino, J.P., Anna, L.J., de la Pradilla. R.F.. \!

1996). Cantrill,A.A., Jarvis,A.N., Osbom, H.M.l.. Our Rakotoarisoa,H.,Perez, R.G., Mangeney. P.. .{.lc : {lu-o. G., Savoia,D., Valentinetti,M.R. f Sl I 'Leonard, J., Mohialdin, S., Reed,D., Ryan.G . Sr 'Piers, E., Kaller, A.M. SL 549 (1996\. 'Pereira, O.2Z.,Chan,T.-H. JOC 61,5406 ( 1996, -.\lexander, C.W., Lin, S.-Y., Dieter, R.K. ./O.vC Baldwin, I.C., Beckett,R.P., Williams, J.NIJ -sI 'Xiang, J., Fuchs,P.L. JACS 118, I 1986 ( 1996, 'Hohmann. M.. Krause, N. CB 128, 85 | ( 1995, :'Barbero, A., Cuadrado, P., Fleming, I.. Gonz:Jc ,1995). : Kocovsky,P., Grech,J.M., Mitchell, w.L, J(f a ttLind"rman. R.J.,Siedlecki,J.M. JOC 61. 619: , I

reagents.18,262-16-r Organocopper/zinc. Methylenation' After the readxr nethylcopper-zincreagentsin the presco alkenes.If the initial produ :nonosubstituted result. Conjugateadditian. The Michaelrca .s donorsrequiresonly catalyticamounlsd

Organocopper/zincreagents235

of ffisubstituted !:., -!'lectivesynthesisr8 l-i .:.r l triflones.

(acid chloride, allylic iollowed by acetylation and treatment with an active electrophile in an bromide) in the presenceof CuCN effects a C-C bond formation with the aldehyde -+ other the Cu transmetallation' umpolung manner. It is important that, during the Sn substituents remain on the tin atom. Therefore, the particular intermediate that bears ,econdary cyclohexyl groups has an advantageover the methyl or butyl derivatives.

OAc

I

82"k(E:Z 'lzt 1\

C5Hl14SnCy3

o -.. :,'n)l enynes.leActually, acetylene rt. ::', rnB rise to (Z)-alkenylsilanes after

'

!' ^ \,/

/\

SOzph

45"/. Fused-ring cyclopropyl carnoli.l E :Lnrng in methanolwith Hg(II) salts: t. : : .rlkyl(methyl)mercury derivatives. i. : .:. the functionalizedcycloalkanols.

F

- / '

,gct l.,re

A - n csHrr- Y o 73 - 92"/"

rDanielmeier. E. ACIEE35'224'7(1996)' K., Schierle,K., Steckhan, :Lind..-un, R.J.,Chen,S. TL36,7799(1995). rJefford, C.W.,McNulty,I.,Lu,Z.-H.,Wang,J.B.HCA79' 1203(1996)' avettel,S.,Vaupel,A., Knochel,P. TL36,1023(1995)' sTsushima, H., Murai,A. Ca 80l (1995) K., Hirade,T., Hasegawa' uchi"fft.A.. comasseto, (1995). 671 SL J.V. 7Hud.lik,P.F.,Ma, D., Bhamidipati' R.S.,Hudrlik,A.M. JOC 6l' 8655(1996)' tNugu-o,S.,Irie,S.,Akita,H. CC2001(1995). nMi.ino. J.p., Anna,L.J., de la pradilla,R.F.,Martinez,M.V., Montero,C., Visa, A. TL 37, 8031

---1\

v.\

Cy = cyclohexyl

OAc

Mecu; RCOX

MescuLrz

(1996). 'oc*t ill, A.A.,Jarvis,A.N', Osbom,H.M.I.'Ouadi,A', Sweeney, J'B' Sf 847(1996)' I rRakotou.i.oa, 1957( 1996)' 15' OM A' P., Alexfis, H., Perez,R.G.,Mangeney, '2Alu*o. G., Savoia, M.R. 252, 12571(1996). D., Valentinetti, r3lronard,J.,Mohialdin,S.,Reed,D., Ryan'G.,Swain,P'A' ?51' 12843(1995)' raPiers, E., Kaller,A.M. SL 549(1996). rsPereira. O.2Z., Chan,T.-H.JOC 61,5406(1996). t6Alexander, C.W.,Lin, S.-Y.,Dieter,R.K. IOMC 503'213(1995)' '7Buld*in.I.C.,Beckett, R.P.,Williams,J.M.J.S 34 (1996). r8xiung,J.,Fuchs,P.L.JACS118,11986(1996). reHohmunn. N. CB 128,851(1995). M.. Krause, '0Barb.ro.A., Cuadrado, A' JCS(PI) 1525 P., Fleming,I.,Gonzalez,A'M', Pulido,F'J', Sanchez' (19e5). ?rKocovsky, P.,Grech,J.M.,Mitchell'W'L- JOC 60' 1482(1995)' 22l-ind".-un.R.J..Siedlecki,J.M. Jo C 6L' 992 (1996).

I Organocopper/zinc reagents. 18, 262-263 t the reaction of aldehydes with (dialkoxyboryl)Aft". Methylenation gives methylcopper-zinc reagents in the presence of BF..OEt2, subsequent heating I,2-diols monosubstituted alkenes. If the initial products are treated with buffered HrOr, bric .tc'p reaction sequenceaccomplishes tJs: . .i.' * ith tricyclohexylstannyllithium'

result. The Michael reaction using functionalized organozincreagents Conjugate addition. amounts of cu(I) species.2Thus, the addition of MeLi to catalytic only as donors requires

236

Organomanganesereagents

an RZnMe followed by exposureto catalytic :rmountsof Mercu(cN)Li, in the presenceof MerSicl effects the transmetallation (from organozinc to lithiocuprate), and the reagent is ready to deliver the functionalized R group to an enone. (E)-Alkenyl trifluoromethyl ketones are prepared by the reaction of the (Z)-$ butyltelluro enone.3

FoC BuTe FO E

THF -600 -> -30o. 3 h

Fo Pti 90./.

is mild enough that chiral cr-r organomanganesehalides can be directll mad Phenylmanganesechlcn Enolization.t catalytic amount of an amine. Quenchine urO

Organogallium reagents. Epoxide opening.' Tertiary alcohols are obtained from the reaction of lithium [B-(E)-trimethylsilylvinyl]trimethylgallatewith 1,1-disubstitutedepoxides. The MEMethers of these alcohols fragment to give ketones on contact with TiCl' The behavior is different from that ofthe (Z)-isomers, which form dihydropyrans.

R,-\

*

: \. \ Me3Ga-

siMe3

rHF; MEM-cr

Lt

rPrrNEt

9^o'\''o" RJ R'l\\

Tict4 sitvte'

52 - 55"/o

B u 3 M n M g B r / T HC Fr

R'MnCl

tsukui, M., Saito,S.,Kanai,G.,Suzuki,A., Miyaura,N. f 52, g15(1996). zlipshutz, B.H.,Wood,M.R.,Tirado,R. "/ACSll7 ,6126(lgg5). 'Mo, X.-S., Huang,Y.-2. SL 180(1995).

R..-g

,zca{'rs

grN

In the prt Addition to multiple bonds. are formed br u 1,4-dienes alkynes.Therefore, with mr a by treatment oalkenyl bromides pror I quench of the reaction observed.5Iodine -+RCOR'. ketone srntlrst A RCOCI

FsC. Ph2CuCN(ZnCl)

B'\

R

Io R'

o Etv\Et

( PhMnCl - PhNHMe

lEr

THF - Sullolane, d 4h

'lnoue,R., Shinokubo, H., Oshima,K. Il 37.i,r-:Cahier,G., Marquais, (1996t S. TL 37,11'73 rFtirstner. H. TL37,7009(1996r. A.. Brunner, 'okada, K., oshima,K., Utimoto,K. "/ACsllt. rrl 5zugueq8., G .X Klement,I., Reddy,C.K.,Cahiez. ocahiez. G..Metais,E. TL36,6449(1995t.

M.V., Rieke,R.D. fL 37. : lq Kim. S.-H.,Hanson, icuhier,G.,Kanaan, M., Clery,P. SL 19I ( 1995,

YC-/6

Organonickel reagents. Alkyl cyanonickelate. Couplings.' preparedin situ from M(CN)2 and RLi at --t rHoriuchi, Y., Taniguchi, M., Oshima, K., Utimoro,K. 24 35,Tgjl (lgg4).

Organomanganese reagents. Couplings. Organomanganesespeciesprepared in situ from MnX, and a Grignard reagent catalyzes the coupling of alkyl halides, including gem-dibromocyclopropanes.r RMncl couples with alkenyl halides in the presenceof Fe(acac),.2Selective manganation of o-bromofluorobenzene using manganese-graphite in THF followed by the coupling enablesthe synthesisofo-fluorostyrenes(10 examples,64-75Vo).3

IKauffmann,T., Nienaber,H. S 207( 1995).

Organotellurium reagents. Diorganotellurides are useful precursorso{ are obtained by treating the tellurides urti difficulty in preparing RLi from RX. Alkylations. B-Lithiocarbonyl slntho rhe bromides by reacting with BuTeLi and available from p-(organotelluro)acroleins.

Organotelluriumreagents

',rnrsof Me2Cu(CN)Li2 in thepresence of ' lithiocuprate),andrhereagentis .1:;..:" :-:Jnaredby the reaction of the (Z)-fi-

C.: 0:It f:

Br\

M"..

/Ca{.rs

B u 3 M n M g B r / T H0Fo ;

Br..

,rcaH::

'

erV

grN

237

,rcaH't"

MN

(94 : 6) 65"k Aditition

to muhiple bonds.

In the presence of MnIr,

Grignard

alkynes. Therefore, 1,4-dienes are formed by using allylmagnesium

FqC

reagents add to

halides.a Cyclization

of

90%

ro-alkenyl bromides by treatment with a mixture of Et2Zn and MnBrr/CuCl has been observed.5Iodine quench of the reaction provides iodomethylcycloalkanes. A ketone synthesis6by the reaction of acid chlorides with RCOCI-+RCOR'. R'MnCl is mild enough that chiral cx-acyloxy ketones can be prepared. Such

u : . ' . i 5 2 .9 1 5( 1 9 9 6 ) . - ' . I 9 9 5) .

organomanganesehalides can be directly made from the halides and Rieke manganese'7 Phenylmanganesechloride deprotonatesketones in the presenceof a Enolization,d catalyt;tcamount of an amine. Quenching with an anhydride gives enol esters'

4 -

. -

-

- A

2

-*: Ph

3 n

o Etv\Et ,hreined from the reaction of lithium i -disubstitutedepoxides. The MEM, 'n contact with TiClr. The behavior is

I

:

irhr dropyrans.

O

v

-o\

,'\'SiMe3 a2 - 55"/.

Tict4

R

!o

R'

THF - Sulfolane, d 4 h

I

'l ol,rncr

1 l"^".,

(EtCO)2O Oo-> rt 2 h

ocoEt I

Etr A "

CHEI

94ok(Z: E 87 : 13)

'lnoue,R., Shinokubo, H., Oshima,K. TL37,5377(1996). :Cuhier,G.,Marquais, S. TL 37,l'173(1996). 'Ftirstner, 9 A., Brunner, H. TL37,700. (1996). 'Okada, K., Oshima,K., Utimoto,K. "/ACs118,6076(1996). 'Riguet,8., Klement,I., Reddy,C.K.,Cahiez,G., Knochel,P. TL37' 5865(1996). 'Cahiez, G.,Metais,E. TL36,6449(1995). M.V.,Rieke,R.D. ZL 37, 219'7(1996). Kim,S.-H.,Hanson, 'Cahiez, M., Clery,P. SL 191(1995). G.,Kanaan,

95% ( R = C 1 6 H 2R 1 ,.

\5.1977(t994)

s :'-. :'.:j-.rl in situ from MnX, and a Grignard irj: - ::iluding gen-dibromocyclopropanes.l ri. . . -' ,,1'Fe(acac):.2Selectivemanganation ---. "r1r!.in THF followed by the coupling c ' . . : ' . . ' . .6 1 - 7 5 V o ) . 3

P h M n C l- P h N H M e

Organonickel reagents. Alkyl cyanonickelates (also cyanocobaltates and cyanoferrates) Couplings.t preparedin situ from M(CN)2 and RLi at -78" couple with organic halides. :

Kauffmann,T., Nienaber,H. S 207( 1995).

Organotellurium reagents. Diorganotellurides are useful precursorsoforganolithium compounds.The latter species are obtained by treating the tellurides with BuLi. This indirect protocol obviates the difficulty in preparing RLi from RX. Alkylotions. $-Lithiocarbonyl synthonsr and propargy\ anions2 are generated from the bromides by reacting with BuTeLi and then BuL\. (Z)-1,3-Butadien-l-yllilhiumr is available from p-(organotelluro)acroleins.

Organotellurimreagents

BuTeTeBu

NaBH4;

BuTe,

:

_cHo

/CHO Ph3P=CH2

BuTe\ ..:,

F

g2o/"

'DaMoub, M.J.,Cassol, T.M. f 5l. | ]9DaMoub,M.J.,Begnini,M.L., Cassol.T Tucci,F.C.,Chieffi,A., Comasseto. J.\'

I BuLi/ THF;

I RcHo OH R{

\:/

/:

85 - 92"/"

The mild conditions for the Te/Li exchange allow the generation of RLi containing a cyano group.aA route to homopropargylic alcohols involves the conversion of propargytc bromides to allenyl butyl tellurides (via Grignard reactions with BuTeBr or reactions with

Organotin reagents.

dnti-Selst ftHydroxyesters.' R,SnH in the presenceof TiCl is unu

a.pEpor ftHydroxy ketones.' rixrure of BurSnH, and BurSnI.. Ttx Desulfurization.r Thionoesrcn :rhen, respectively,with P}\SnH-AIB)

OBn

BurTe in the presence of NaBHo [however, the latter reaction is limited to 3-bromo- l-alkynesl) and then to propargyllithium reagents.5 Enyne and arylalkene synthesis from alkenyl tellurides can proceed witb transmetallationto give Zn species.6'7 Alternatively, the partial reduction of 1,3-diynesvia hydrotelluration,Tell,i exchange,and protonation also provides (E)-enynes.8

Fluorous tin reagents,' A geo .elow. These compounds have su Ph.P)PdCl"with LiCl as an additire -

-

p

h

EUtetetJu NaBHa

[:'n TeBu

BuLi ; Hzo

_,[:,n

EIOH A

80/"

o,tunsaturated acids and esters. Alkenyl tellurides of defined constitution and configuration can be prepared from alkynes.eTreating such tellurides with BuLi and co. or CICOOR leadsto the enoic acidsor esters.l0 Di-(Z)-alkenyl tellurides obtained from the ft(Z)-Alkenyl[cyclo]alkanones.tt hydrotelluration of alkynes undergo Te/cu exchange[e.g., with Burcu(cN)Lir]. conjugate addition to alkenones (including cycloalkenones) gives the substituted ketones. Reaction with epoxides furnishes (Z)-homoallylic alcohols.

rlnoue, T., Atarashi,Y., Kambe,N., Ogawa,A., Sonoda,N. Sl, 209 (1995). 'Kanda,T., Ando, Y., Kato,S.,Kambe,N., Sonoda,N. 5L745(tggs'). 3Mo,X.-S.,Huang, Y.-2. TL36,3539(t9g5). -Kanda, T., Kato,S.,Sugino,T., Kambe,N., Ogawa,A., Sonoda, N. S 1102(1995). -Dabdoub, M.J.,Rotta,J.C.c.SZ526(1996). 6deArau.lo, M.A.,Comasseto, J.V.SZ 1145(1995). 'Terao, J.,Kambe,N., Sonoda, N. TL37,474I (1996). oDabdoub, M.J.,Dabdoub, V.B. 251. 9839(1995).

thSnCl3

1

lMgCH2CH2CoF1s-

ClSn(CFl2Cft2CsF

Polystyrene-supported tin hy&il rreparedfrom dichloromethylcvclo

l l r

I T-cHc], ,/\V\

organotinreagents 239

:-,P=cHz

)

BuTe, F .'I

92"/"

eDabdoub, T.M. T51, 12971(1995). M.J.,Cassol, r'babdoub, P'G'' Silveira'C'C'TL36'7623(1995)' T.M. Guerrero, M.J.,Begnini,M.L., Cassol, :rTucci,F.C.,Chieffi,A., Comasseto, J.V.,Marino,I'P' JOC 6L'4975(1996)'

B u L/ir H F ;

+ RcHo OH

85'92"/" r< .: '\\ the generation of RLi containing a r. . rnrolves the conversionofpropargylic ar,: :r,retions with BuTeBr or reactions with rrr rr. the latter reaction is limited to

Organotin reagents. of a-methyl p-alkylketo esters by ftHyilrory esters.r anti-Selective reduction is unusual. R.SnH in the presenceof TiClo pHyilroxy ketones.2 cr,p-Epoxy ketones undergo reductive ring cleavage with a mixture of BuSnH" and Bu,SnIr. The actual reagent is ButSnHI' Thionoest"rs *d thionolactonesareconverted to ethersandcyclic OesutfuiZaAon.3 erhers,respectively,with P\SnH-AIBN in refluxing toluene.(10 examples"T2-99vo).

OBn

,,,,,toan

l,--: :cegents.5 r ., ir'nr I tellurides can proceed with [r r . rhe partial reductionof l,3-diynes via 11 : \,, provides1E)-enynes.8

OBn Ph3SnH- AIBN

toe"

+

PhMe,11d

95% is shown Fluorous tin reagents,4 A general method for the syntheis of the reagents using coupling in Stille applied been below. These compounds have successfully 80'' at DMF-THF rPh.P)PdCl, with LiCl as an additive in

B u L i; T e 3-

Hzo

--[-:'n PhSnCl3 a

lMgCH2CH2CoFIg-

BrSn(CH2CH2C6F13)3

PhSn(CH2CH2C6F13)3

I nrl,t

I

.:.. :.'llurides of defined constitution and T::.:r:1! suchtellurideswith BuLi and CO.

C | S n ( C H 2 C H 2 C 6 F 1 3 ) 3 +A r - R

I

2.. r.n\l tellurides obtained from the :|r: --' L'.s..with Bu2Cu(CN)Lirl. Conjugate G.. rr\c's the substitutedketones.Reaction l

-

o , :.. \ JI-209( 1995). -15 ( 1995). . \ .. N. S 1102(1995). l. 1 \ 'n{xla.

9.

ArSn(CH2CH2C6F1 3)g (Ph3P)2PdCl2 Licl THF. DMF

tin hydride.5 With the use of this reagent, tropones are Polystyrene-supported preparedfrom dichloromethylcyclohexadienones

o

o

/t.,"0 ),2\

@snH nreN PhMe, 8d

\--\./ ( ) .:\ 76"/"

AO

reagents Organozinc

tSato,T., Nishio,M., Otera,J. SZ965(1995). 'Kawakami,T., Shibata,I., Baba,A. JOC 61,82 (1996). 3Nicolaou, Miller,N.D.CC 1583(1995). K.C.,Sato,M., Theodorakis,8.A., ocurr*, D.P.,Hoshino,M. JOC 61,6480(1996). sDygutsch, M. SZ 363(1994). D.P.,Neumann,W.P.,Peterseim,

R3

(Ro)lnL,

l 7 Arsoi /

R2

rR1

Organovanadium reagents. The combination of an allyl halide, VC! and Zn canbe used to allylate Altylation,r carbonyl compounds. Sequential Grignard reaction of a ketone and treatment with allyl bromide and VcL(tmeda), together complete the deoxygenative alkylation. Aldehydes undergo reductive coupling with Zn, MgSiCl, and Pinacolization.' catalytic amounts of CpV(CO), (3 examples,70-9OVo).Such a diol product is actually tied

,rddition of diorganozincs. Ho*erer.

up as dioxolane (with one equivalent of the original aldehyde).

TMSCI,

rKataoka, Y., Makihira,I., Akiyama,H., Tani,K.TL36,6495(1995). 2Hirao,T., Hasegawa, T., Muguruma,Y., Ikeda,l. JOC 61,366(1996).

conjugate additione quite well.

Organozinc reagents. 13, 220-222; 14, 233-235; 15, 238-240; 16, 246-248; l7, 228-234;18,264-265 1,3-Dizincs.t The preparation of one such speciesis illustrated below.

/

HBEI2

aBEt2

Et2zn

Conjugate

additians.

A Cut I r

uncatalyzed reactions are qr

Eick. H.. Knochel. P. ACIEE35.218 t 19 :Chemla, F . , N o r m a n t ,J . T L 3 6 , 3 1 5 7 r l 9 'KI.-"nl I.. Knochel, P. SL I I 13 ( l99S ' 'Hata, T., Shimizu,M., Hiyama, T. 5L t-rl 'Klement, I., Lennick, K., Tucker.C.E.. Xr Harada,T., Wada, H., Oku, A. JOC fi.5 Kitamura, M., Miki, T., Nakano. K.. Soy 'Reddy, C.K., Devasagayaraj,A.. Knchd 'Vaughan, A., Singer, R.D. Tl 36. 568-1, I

/-zn\

L r r , r + L r = , r + Y - J

Alrohols and hydroperoxides. The exposureof organozinc halides to air-HMPA in THF affords alcohols (10 examples, 56-98Vo)? On the other hand, aeration in perfluorohexanesat -78o leads to alkyt hydroperoxides.l The zinc carbenoid derived from CFBr, andB\Zn adds to aldehydes readily to form RCH(OH)CFBr'.a The remarkable chemoselectivity favoring aldehydesto ketones (> 99: I ) is in stark contrast to that of LiCFBr, which reacts almost indiscriminately. Nitriles. The reaction of organozincs with TsCN to give nitriled is particularly interesting in cases that involve homopropargylic sulfonates, because lzincoalkylidenecyclopropanesare formed, and thesecan be derivatized9

Osmiumtetroxide.13,222-?25. ll. 236-240;18,265-267 A symmetricdihydrory lationdihydroxylationof c heterogeneous usingPt electrodesin urdrr method2 quantitiesof p requiresmuch-reduced Homoallylicalcoholderivattresr by arenow available 1.2-alkanediols havebeenc iretterenantioselectivities

r'^'.ro-.r\ i l i l

TsCN

"

THF -78o-> rt 69/"

({

t

9o""

-

.j

Osmium tetroxide

ft \:

R3

/

Jq-i

I

R2

.r'

(R4)gznLi

l 2 arsoi

tC1583(1995).

E+

THF

H-

.^1 n

R2/"

lr:... ridehyde). _rr -.:qi r 1995). X 6l :f'fi(1996). f-:< I 5. 138-240: 16, 246-248; 17, :l .:\'.re\ is illustratedbelow.

it:

-

Et2Ln

t.

r-zn/

Conjugate a.dditions. A Cu(I)-sulfonamide systemT is useful for catalyzing the addition of diorganozincs. However, in N-methylpyrrolidinone and in the presence of TMSCI, uncatalyzed reactions are quite efficient.8 Trialkylsilyl(dialkyl)zincates undergo conjugate additionequite well. 'Eick,H., Knochel, P.ACIEE35,218(1996). :Chemla, F., Normant, J. TL36,3157(1995). rKl"-"nt, I., Knochel, P. SZ 1I l3 (1995). tHatu, T., Shirnizu, M., Hiyama,T. Sf 831(1996). iKle."nt, I., Lennick,K., Tucker,C.E.,Knochel,P. TL34,4623 (1993). nHarada, T., Wada,H., Oku,A. JOC 60,5370(1995). M., Miki, T., Nakano,K., Noyori,R. TL37,5l4l (1996). Kitamura, sR.ddy,C.K.,Devasagayaraj, A., Knochel,P. TL 37, 4495(1996). 'Vaughan, A., Singer,R.D.fr36,5683 (1995).

\

Y^J 90"/"

r\-:r 't ()rsanozinchalidesto air-HMPA in On the other hand. aeration in F ?i

r[,.r

E = S i M e g ,C O O E I, C O R, cN,cH(oH)R,l

h:...:e. \'Cl andzncanbe usedto allylate cr: : rri a ketoneand treatmentwith allyl F Jj,,\\ genativealkylation. du,::re coupling with Zn, MgSiCl, and I * . r Such a diol product is actually tied

.T. p61e1qa

)>-612611P+

,R1

Ul

',ia..l

d i'. I.n adds to aldehydes readily to form t\ :: . : J\ oring aldehydesto ketones(> 99:l ) r:. r. :r)ostindiscriminately. r::: T.CN to give nitriled is particularly

Osmium tetroxide. 13,222-225: 14, 235-239; 15, 240-241;16, 249-253; 17, 236-240:18.265-267 Efficient and practical polymeric catalysts for Asymmetric dihydrorylation. heterogeneous dihydroxylation of olefins have been developed.r An electrochemical method2using Pt electrodesin undivided cells enables a synthesisof chiral 1,2-diols that requiresmuch-reducedquantities of potassium osmateand KrFe(CN)u. Homoallylic alcohol derivativesundergo functionalization.r3-Diphenylphosphinoyl1,2-alkanediolsare now available by this method.aNew ligands (1,2) that show equal or have beendeveloped.5 betterenantioselectivities

sulfonates, because ln :: r.rgylic ti'.r.: ,.rn be derivatized9

r^-")"

%or"

K2OSO4- K3Fe(CN)6 (DHOD)2PYZD K2CO3/ aq. I-BUOH oo, 4h

"o"atolHo-'

%or"

99% (enantios.95.5 : 4.5)

AZ

Osmiumtetroxide-N-methylmorpholineoxide

lo-DHol O-DHQD

Ph--N-A^,

I

I

ll

tn.Z-A*

'i

l

o.A-*t{-rzN ' ' l

l

DHQD= dihydroquinidine l

on'\-\ZN

O.DHQD lo-DHol

lo-DHol O.DHQD DHQ = dihydroquinine

l

Oxalyl chloride. 17, 241-242; 18. 267-lN An improved prtr-ct Formarnides.' :Lrrmicacid in combinationwith oxalr I chkr Dc 2H-Azirine-2-carboxllicesten.-

I O.DHQD

to-DHol (2)

(1)

2.. Hindlel, \larko,I.E.,Giles,P.R.,Janousek, J.S.RTCPI14,239 (1995). Sr'endsen,

rcurs under the Swern oxidation conditton Aminohydroxylation. Chloramine-T is used in the reaction,6 but smaller organic substituents on the sulfur atom of the chloramine salts have higher selectivities. Thus. chloramine-M [MeSOrN(Na)Cl] is better.T N-Halocarbamate salts are more efficient reagents.8

T., Ito, J.,Tsutsui,C. CPB42. l9il ' Krtagawa, 'Gentilucci, L., Grijzen,Y., Thijs,L., Zuanentr

Oxygen. 18,268-269 Oxidation of secondary alcahok. - (DHQ)2-PHAL K2OSO2(OH)a

,\'cooMe

NHMs ,,'. -COOMe

MeSO2N(Na)Cl/ProH, H2O

=

OH 65% (9s% ee)

'Song, C.E., Yang, J.W., Ha, H.J., Lee, S.-G. TA7,645 (1996). 'Torii, S., Liu, P., Tanaka,H. CL319 (1995);Torii, S., Liu, P., Bhuvaneswari,N., Amatore,C., Jutan( -4. JOC 61,3055 (l 996). rCorey,8.J., Guzman-Perez,A., Noe, M.C. fZ 36, 3481 (1995). -O'Brien, P., Warren, S. JCS(PI ) 2129 (1996). sBecker, H., King, S.B., Taniguchi,M., Vanhessche,K.P.M., Sharpless,K.B. JOC 60, 3940 (1995). 'Li, G., Chang,H.-T., Sharpless,K.B.ACIEE 35,451 (1996). 'Rudolph, J., Sennhenn,P.C., Vlaar, C.P., Sharpless,K.B. ACIEE35,2810 (1996). ol-i, G., Angert, H.H., Sharpless,KB. ACIEE35,2813 (1996).

:equire a metal catalyst.r Baeyer-Villigeroxi.dation.

r\ygen can be achievedby using a Pd conq Drr Alcohols from organometallbs.

.rrganozincsis useful.6 The former reactrr elcohols with retention of configuration Lithiated amines ft.r N-Alkylation.l Treatment with oxygen accomplishes *r

nitrogen. Serera Oxidation of hydrocarbons. .ombination effect the oxidation of al\a

CuClr/I 8-crown-6,eand vanadium-sub\trr ron has dramatic effects on the courst of ;vclohexeneby (1) and (2), respectirelrl

,n"^'Ycoo"" Z-v I

l r l

tr/}'\ tl

OAc O OsO4- NMO

.........................._ Me2CO- H2O

I

ll

vo-?o

r.r r.o-

l l l

,,i/7

MeOOC

HO 8 9 %( s y n :a n t i 1 9 : 1 )

The O.

::rethoxyaryl aldehydes mainly to an I iorm Oxidation of sulftdes. The conr errx

Osmium tetroxide-N-methylmorpholineoxide. Dihydrorylation.r Baylis-Hillmanadductsundergosyn-selective dihydroxylation.

OAc O

Tl

(1)

Y

Oxygen

)

'Ma'.ko, DHOD= dihydroquinidine

I.E., Giles, P.R., Janousek,Z.,Hindley, N.J., Declercq,J.-P.,Tinant, B., Feneau-Dupont,J, Svendsen,J.S. R?CP I14,239 (1995).

DHO = dihydroquinine

Oxalyl chlorid e. 17, 241-242: 18, 267 -268 An improved procedure for the formylation of amines involves Formamides.t formic acid in combination with oxalyl chloride and imidazole. 2H-Azirine-2-carboxyli.c esters.t Dehydrogenation of aziridine-2-carboxylic esters

): i

occurs under the Swern oxidation conditions. rr' :caction,bbut smaller organic t. :..:\e higher selectivities.Thus, lr.::)rte salts are more efficient

NHMs )

,1r,cooMe : OH 65% (95% ee)

N.,Amatore, C.,Jutand, B:.. ..,nc.rvari,

' Kitugu*u,T., Ito,J.,Tsutsui, C. CPB42, 1931( 1994). :Gentilucci, L., Grijzen,Y., Thijs,L., Zwanenburg,BTL36' 4665( 1995)

Oxygen. 18,268-269 The oxidation in the presenceofPhCHO does not oxidation of secondary alcohols. require a metal catalyst.r The Orll-PTCHO/metal catalyst system transforms Baeyer-Villiger oxidation. metlroxyarylaldehydesmainly to aryl lormatesl Oxidation of sulftd.es. The conversion of sulfides to either sulfoxides or sulfones by oxygen can be achievedby using a Pd complexsor isobutyraldehyde'a organoboranet' and of oxidation Alcoholsfrom organometallic,s. Direct organozincs is useful.6 The former reaction in perfluoroalkanes (e.g., CrF,tBr) provides alcohols with retention of configuration. Lithiated amines form amidocuprates with organocopper reagents. N-Atkylatian.T Treatment with oxygen accomplishes the transfer of an organic residue from copper to nltrogen.

iL..-:-'... K.B. IOC ffi,3940 (1995). 'I.; .1St8l0 (1996).

several variants of the aldehyde-metal salt oxidati.on of hyilrocarbons. combination effect the oxidation of alkanes and alkenes, among them salen-cobalt,8 A changeof ligand for the cobalt zeolites.rO CuClr/I8-crown-6,eand vanadium-substituted ion has dramatic effects on the course of oxidation [allylic oxidation vs. epoxidation of cyclohexeneby (1) and (2), respectivelyl.

/:N

|

\'*/

\

Fr--uo-^iz_l \ / \:./

OAc O

r/(

='tny''t'

2Cl

MeOOC HO : : ' , S y n: a n t i 1 9 : 1 )

N=\

(1)

(2)

U4

Ozone

Nitroalkanes to carbonyl compounds.lr (TMEDA. Copper complexes 2,2-bipyidine, 1,10-phenanthroline)promote the conversion in quantitative yields. Interntpted Pauson-Khand reaction.rz Admitting oxygen to the system while heating the enyne complex yields 1-acyl-2-methylcyclopentene as the product of an

Ozonides o a-Keto aci.d ilerivatives. .ilkylacroleins on treatment with a prehear< a-keto acid derivatives.2

intramolecular reaction.

o

o

Co2(CO)6

/ \

\

\

A

OslCH2Cl2i

t.--\-.|J

Et3N- CH2Br2

. \

(-\.4* tl

A

-

63'/"

PhMe (O2) B = Bn. Et. CN...

-

o -

54 - 75o/o

c[-Keto acid derivatives are also forrncd b rchoudary, B.M., Sudha,Y. SC ?5,1651 (1996). 'Anoune, N., Lanteri,P., Longeray,R., Arnaud,C. TL36,6679 (lgg5). 3Aldea, R., Alper, H. JOC 60,8365 (1995). -Khanna, V., Maikap, G.C., Iqbal, J. TL37,3367 (1996). -Klement, I., Knochel, P. Sa 1004(1996). nKlement, I., Ludens, H., Knochel,P. TL36,316l (1995). 'Alberti, A., Cane, F., Dembech, P.,Lazzari,D., Ricci, A., Seconi, G. JOC 61, 1677(1996). oReddy, M.M., Punniyamurthy,T., Iqbal, J. TL36,159 (1995). 'Komiya, N., Naota,T., Murahashi,S.-1.TL37,1633 (1996). r0N"u-*n, R., Khenkin, A.M. CC 2643 (1996). ''Balogh-Hetgovich, E., Kaizer, J., Speier, G. CL 573 (1996). ''Krafft, M.8., Wilson, A.M., Dasse,O.A., Shao,B., Cheung,Y.Y., Fu, Z.,Bonaga,L.V.R., Mollman, M.K. "/ACS118, 6080 (1996).

o

o +

"Ao,

03/ c|t& PQP=CxCfi Et3N Cnl

2-Cycloalkenones,s Ozonoll'sis of fi alcohols with alkaline workup leads diretrll products from ring cleavage.

U.,Dietz,T.,Witzel,A. I-4 l4g5(1gg5). lQuast,

Ozone.13,229; 15,243-244; 17, 253-254; 18,2'10-27 2 Aldehydes. An effectivenewreagentfor thereductivequenchingofozonolysisis the sodiumsaltof 3,3'-thiobis(propanoic acid).'

_cr

qplJnsaturatedesters.' Ozonidcsc

\v

'Chambers, R.D., Sandford,G., Shah,A,. SC 26,1861 (1996). 'Seto, H., Yoshida,K., Yoshida,S., Shimizu, T., Seki, H., Hoshino,M. TL 37,4ljg (1996). -Minakata, S., Imai, 8., Ohshima, Y., Inaki, K., Ryu, I., Komatsu, M., Ohshiro, y. CL 19 (1996).

v

PP?b

("n , Oxygen,singlet.13,228-229;14,247;15,243:16,257-258;17,251-253;18,269-270 Tetrakis(2,6-dichlorophenyl)polphyrin is a superior sensitizerfor singlet oxygen generation.lPhotooxidation canbe carriedout in perfluorocarbons with excellentresults.2 Oxidationof ethers. With benzilassensitizer, thephotooxidation of ethersresultsin the formationof esters.3 This reactionmay be comparedwith the processmediatedby Cu0D.a

R

,\

Ph

Ph

>< l l

X.*

l

o3tc+2ct2 +

(TMEDA. complexes Fu'oMe t

66%

tl

l-cooet l major

. '- .,:Ipulatedto form either fused or

Arylation with onium salts. Diaryliodonium8'e and arenediazonium tetrafluoroboratesl0are suitable arylating agents.An important difference with conventional coupling is that cinnamyl alcohols are obtained from the reaction of allylic alcohols with aryliodonium salts8insteadof B-aryl ketones,due to internal chelation ofthe positive Pd by the OH group, preventing syr-alignment of the hydrogen atom at the carbinyl center. Interestingly, benzylic quaternaryammonium saltsalso undergo coupling, which, with ethyl acrylate, furnishes ethyl 4-aryl-3-butenoate.I I Suzuki couplings. In analogy to the Heck reaction, the use of arenediazoniumsalts in the Suzuki coupling is successful.12 The preparationof 1,2-dicyclopropylethenesby such a method gives quite satisfactoryresults.r3

rh}'z\,B-o/

/--\ o-\ // | -

+

'Mo*

Pd(OAc)2- PPh3 K2CO3, Bu4NCl DMF- H2O, 9Oo

250

Palladium(Il)acetate

Homologation of allylic halides to give B,y-unsaturatedesters in a Carboxylati.on CO, EtOH],t4 lactonization of long-chained system two-phase [Pd(OAc)r, I!CO' (e.g., for the synthesis of exaltolide),ls and carboxylation of arenesr6 ol-hydroxyalkynes

a"'tzB'

trroJ

(-I--ot

KPor

proceedsunder very mild conditions.

Reardon,P., Metts, S., Crittendon, C.. Daugfrnn '\toreno-Manas, M., Perez, M., Pleixats. R. IL ! Rigby, J.H., Hughes,R.C., Heeg,M.J. J.'tCSll"l 'samizu, K., Ogasawara,K. H 41, 1627( 199J, '\'illar, L., Bullock, J.P.,Khan, M.M.. Nagarap F. Tamariz,J. JOMC 517,9 (1996). 'Cacchi, S., Ciattini, P.G., Morera, E.. Pace.P 5 Crisp, G.T., Gebauer,M.G. Z 52, l22165r | 996 , 'Kang, S.-K., Lee, H.-W., Jang,S.-B.. Kim. T -H -Kang, S.-K., Lee, H.-W., Jang,S.-B.. Ho. P -S t

Pd(OAc)2- CO. Et3N /

THF

r t , 1 2h

Addition to muhiple bonds. The addition of benzenethiol to allenes to give 2-phenylthio-1-alkenes,l7 and the conjugate transfer of an aryl group from ArtSbCl to enones and enalsr8 are typical reactions using Pd(OAc), as a catalyst. Under reductive conditions (HCOOK present), the delivery of an aryl or alkenyl group from the providesprecursors correspondinghalide to 3,3-dialkoxy-1-(o-acetaminoaryl)-1-propynes I e quinolines. of 3-substituted

.OMe

///.cH(oEt\2 a.\,.'

I

ll 'NHAc *

.-^.*. oMe Pd(oAc)2 I U

r-'v

Sengupta,S., Bhattacharyya, S. SC 26. ll I t lS Pan,Y., Zhang,2., Hu, H. S 245 ( 1995l. 'Darses, S., Jeffery,T., Genet,J.-P.,Braler. J -L Charette.A.B., Giroux, A. JOC 61. 87l 8 t 1996 'Kr1i, J., Okano,T., Higashimae,Y.. Fukur. \- 8 'Setoh, M., Yamada,O., Ogasawara,K. Il $. !i -Taniguchi, Y., Yamaoka, Y., Nakata K.. Tabf Ogawa,A., Kawakami, J., Sonoda,N.. Hrrr'- T 'Cho, C.S.,Motofusa, S.-I., Ohe, K.. Uemura-S -Cacchi. S., Fabrizi, G., Marinelli, F.. Moro. L. : l-arock, R.C., Hightower, T.R., Kraus. G.A.. lL : Rcinn,M., Biickvall, J.-E.,Andersson,P.G. n : ::Larock, R.C., Hightower, T.R., Hasvold. L,.rr . I :'Pitre. S.V., Vankar, P.S.,Vankar, Y.D. f 52- I l

HCOOK DMF. 4oo

Palladium0Dacetate-lithium bromilc. y,6-Unsaturatedcarbonyl compout&-rBr in the presenceof conjugatedcarh .iJdition.rThe reactionis not confinedto : :rom alkynoicacidswith the simultaneou -'ertainlya usefulsyntheticprocess. The conversion of silyl enol ethers to enones can be effected by Oxidation, Pd(OAc), in DMSO with molecular oxygen to recycle the Pd.20This system is also useful for heterocyclization of 8,e-unsaturatedalcohols and amides to form 2-vinylfurans2l and -pyrrolidines.22 Alcohols are oxidized in a nonpolar solvent with Pd(OAc)r-&COr. Allylic alcohols containing a bromine substituent on the double bond undergo oxidation and debromination.23

/

o

-

)n

cooH

+

\,,\"

Pd(OA.h UBr

Palladium(Il)acetate-lithiumbromide

estersin a htr :.ri. t0 give B,T-unsaturated F.:,'il .' lactonizationof long-chained r".: .:Jct.r5and carboxylationof arenesr6

(^'Y''

Pd(OAc)2

\y'--oH

K2CO3 / PhH

251

t i l 8s"/.

)

27"/"

: hcnzenethiol to allenes to givc li..i.: ,\i an aryl group from ArrSbCl to P.: , r \1. as a catalyst.Under reductive o: :. .rnl or alkenyl group from the tr.:- .:n I t- I -propynes provides precursoF c

OMe

k

Reardon,P., Metts, S., Crittendon, C., Daugherity, P., Parsons,E.J., Diminnie, J. OM 14,3810 (1995). -Moreno-Manas, M., Perez,M., Pleixats,R.TL37,7449 (1996). 'Rigby, J.H., Hughes,R.C., Heeg,M.J. ./ACS 117,7834 (1995). 'Samizu, K., Ogasawara,K. H 41,1627 (1995). 'Villar, L., Bullock, J.P.,Khan, M.M., Nagarajan,A., Bates,R.W., Bott, S.G., Zepeda,G., Delgado, F., Tamariz,I. JOMC 5L7,9 ( 1996). "Cacchi, S., Ciattini, P.G.,Morera,8., Pace,P. SZ 545 (1996). Crisp, G.T., Gebauer,M.G. 252, 12465 (1996). 'Kang, S.-K., Lee, H.-W., Jang,S.-B., Kim, T.-H., Pyun, S.-J.JOC 61,2604 (1996). 'Kang, S.-K., Lee, H.-W., Jang,S.-8., Ho, P.-S. CC 835 (1996). 'sengupta, S., Bhattacharyya,S. SC26, 231 (1996). 'Pan, Y., Zhang,Z., Hu, H. S 245 (1995). -Darses, S., Jeffery,T., Genet,J.-P.,Brayer,J.-L., Demoute,I.-P..TL37,3857 (1996). Charette,A.B., Giroux, A. JOC 61,8718 (1996). 'K1i, J., Okano, T., Higashimae,Y., Fukui, Y. BCSJ 69,1029 (1996). :Setoh, M., Yamada,O., Ogasawara,K. H 40,539 (1995). Taniguchi, Y., Yamaoka, Y., Nakata, K., Takaki, K., Fujiwara, Y . CL 345 (1995). Ogawa,A., Kawakami, J., Sonoda,N., Hirao, T. JOC 6l,416l (1996). 'Cho, C.S., Motofusa,S.-I., Ohe, K., Uemura,S. BCSJ 69, 2341 (1996). 'Cacchi, S., Fabrizi, G., Marinelli, F., Moro, L., Pace,P. T 52, 10225 (1996). Larock, R.C., Hightower,T.R., Kraus, G.A., Hahn, P.,Zheng,D. TL36,2423 (1995). R:, ./ \ O4O/ CO - MeoH

+

Bu /-\

MeOOC

H-,

R R '

(rcfor SiM€3

sict ihl€o:

COOMe

200

--rRCN.6

RCONH2

35"k

38'/"

(HCHO)n .

2-M ethylenecy cloalkane- I -metlua&. formaldehyde (from paraformaldehldc methylcycloalkenes in thepresence of SnCl

).' \ /

Bu

+

with formic

This dehl,drauo

acid and (HCHO),

in }teCl substituted undergo the dehydration *'irhour

'Gabriele, B., Salemo,G., Cosra,M., Chiusoli,G.PJOMC 503,21(1995\.

Paraformaldehyde. 18, 284 Hydroxymethylatian. Hydroxymethylation of l-alkynes and lactams, including is easily achieved. The alkynes are activatedby treatment with EtMgBr,l and the B-lactams, lactam alkylation is aided by ultrasound. 4-Dialkylamino-1-(trimethylsilyl)-1,2-butadienes.' Iminium ions generatedby the condensation of (HCHO), secondary amines with react readily 1,1-bis(trimethylsilyl)-2-propyne, with expulsion of a trimethylsilyl group.

:.Zwierzak,A., Tomassy,B. SC 26,3593 tl996r -Jouglet,8., Oumoch, S., Rousseau,C. SC L(. ,1t 'M'Baze Meva'a, L., Pornet,J. 5C26,3351 r I9{ \yerges, M., Balazs,L., Kadas,I., Biner. 1..Kor iTorii, S., Okumoto, H., Genba, A. CL74i tlg%l nKrawczyk, H. SC25,641 (1995). Monti, H., Feraud,M. SC ?,6,l72l (199 6l. 'Heck, M.-P., Wagner, A., Mioskowski, C. JOC a

with Pentaarylantimony. Arylations.'

EI2NH +

(HCHO)n

' CSA/MECN ----------------

Et2N1 t:C-

--cH(siMq)2 65o,2h

Reaction of these reagerl

turnishes alcohols and aryl ketones, respecur at a low temperature (-78"

to room temperl

siMe3 62o/"

'Fuliwara,

M., Tanaka, M., Baba, A., Ando. H . So

Pentaarylantimony 263

MPMO.

lr

/,o -ctro

tcr,o

R+R=CO

.-\

Azomethine ylides. These ylides can be prepared from N-alkylglycinea or .v-alkyl(trimethylsilylmethyl)amines5 by reaction with (HCHo),. The reactive speciesare rapped as 1,3-dipolar cycloadducts, namely, and 3,4-disubstitutedpynolidines.

-.9"

95\

2-Functionalized acrylic acids.6 In a one-step reaction, malonic acid, paraformaldehyde,and a nucleophile (e.g., RR'NH) give such products in good yields (5 examples,78-92Vo).

r::r. T.-H.JOCffi,4678(1995).

cooH /cooH cooH

in ^: .:rJes * ith the help of this catalysr 0::.:.

73"h

2-Methylenecycloalkane-I-methanols.T

Activation with MerAlCl makes paraformaldehyde) receptive ro attack by l-trimethylsilylmethylcycloalkenesin the presenceof SnClo.The reaction is a silicon-directedene reaction. iormaldehyde (from

nr\' :: ,,i l-substituteddimethyl maleatcs .. .ue fbllowed.

il,r

R R '

R R ' )t'

\ /

Bu /-\

MeOOC

NeHCO3/ HzO

/ A..,,..^,, o H \

RCONHz -+RCN.8 This dehydration of primary amides is performed by heating with formic acid and (HCHO), in MecN. Amides in which the o-position is fully substitutedundergo the dehydration without any problem. 3t-t 31 119951.

r : i-elkynes and lactams, including tr:r',: -\ rreatmentwith EtMgBr,l and thc Iminium ions generatedby the HCHO), react readily h with .: ::rmethylsilyl group. c: .nc,.

ltrN-r

!':

\

90 - 95%

COOMe

F',

/t

SiMed

(HcHo)n. i/b2Atct. + SnOlr/ CH?CI2;

t,Zwierzak, A., Tomassy,B. SC 26,3593(1996). -Jouglet, B., Oumoch, S.,Rousseau, G. SC25,3869(1995). rM'Bur" Meva'a, L., Pornet, J. SC 26,3351(1996). M., Balazs,L., Kadas,I., Bitrer,I., Kovesdi,I., Toke,L. T 51,6783(1995). !y"rg"r, 5To.ii,S.,Okumoto, H., Genba,A. CL747 O996\. 6Krawczyk, H. SC25,641(1995). 'Monti, H., Feraud,M. SC 26, 1721(1996). oHeck, M.-P.,Wagner, A., Mioskowski,C. JOC 61,6486(1996).

Pentaarylantimony. Arylations.' Reaction of thesereagentswith carbonyl compoundsand acid chlorides furnishes alcohols and aryl ketones,respectively. The former reaction requires a Lewis acid

-c-

at a low temperature(-78" to room temperature). SiMe3

'Fuiiwara, M., Tanaka,M., Baba,A., Ando,H., Souma,y. JOMC S0B,49 (1996').

264

Phase-transfercatalysts

Pentamethylcyclopentadienylrhenium(V) trioxide. The catalytic elimination using Cp*ReO, in the presence Alkenes from I,2-diols.' of PhrP in hot chlorobenzeneis stereoselective.This method is potentially competitive with the standardCorey-Winter procedure.

-AoH

o=]-

1+&t

--l--o

oH

o,lf_-o o

PPh3 t

P h c ,r 1 2 d , 8 0h

i-y\ --Fo

,o+ "

'Cook, M.A../ACS118,9448(1996). G.K.,Andrews,

Allylic phenll sultc C-Allqlations. ,rnionsare generatedin the presenceof aqu With dibromoalkanes,cyclic products are, ,rndcr-substitutedphenylacetonitrilesreer

J

+

\,/

Ph{

B,AB.

The PTC technique has been advantag rylationrs of alkynes. For the Heck rcet .rllows a reaction in water, aqueouvorl

.-onditions.r6 In the presenceof l8-crown-6. concurr Perfluoro-2n3-dialkyloxaziridines. 18, 285 Ketonesfrom ethers.' Alkyl ethers-particularly methyl alkyl ethers-are oxidized to ketones in Freon-l I at room temperatureby the oxaziridines. Thus, 2-adamantanoneis obtained in 9 1Voyield from 2-methoxyadamantane.

Heck reaction of a terminal double bond o{

- | , jP *

tA-on", A., Bemardi,R., Cavicchioli,M., Resnati,G. JOC 60,2314(1995).

Phase-transfer catalysts. 13, 239-240; 15, 252-253; 18, 286-289 With the use of poly(ethylene glycol) [PEG] as a phase-transfer Etheritication (PTC), diaryloxymethanes are readily preparedr from ArOK and CHrCl, in catalyst The methanol at room temperature. samecatalyst is usedin a synthesisof triaryl cyanurates2 from cyanuric chloride. A useful method for accessto vinyl ethers involves the addition of alcohols to alkynes in the presenceof 18-crown-6.rThe (Z)-isomersare predominant. The monobenzylation of symmetrical diols with BnBr, KOH and l8-crown-6 is highly efficient (7 examples,82-9l%o).4 N-AllElations. Smooth alkylation of pyrrole without solvent,s synthesis of diarylamines by N-arylation with activated aryl halides,6 and the direct conversion of o-nitrotrifluoroacetanilides to N-alkylaminesTare performed under PTC. 2-Bromoethyl methacrylate is converted into methyl N-(methacryloyloxy)ethyl carbamateon treatment with KOCN in methanol in the presenceof BuoNBr.8 Synthesis of organosulfur compounds. When catalyzed by PEG-400, the reaction of alkyl and acyl halides with sulfur gives dialkyl and diacyl disulfides, respectively.e'roThe opening of epoxide with sodium arenesulfinatesusing polysorbate-8Oas a PTC constitutes a simple route to B-hydroxy sulfones.rr

KH,

$coo"" ,*r Carb ony lation and hydroformy latiot ;arbonylationof benzylic halides.r8 A ma of propargylic alcohols into 2-alkylidern similar results are obtained from the carbtr

N|(CN)2- LaCl3.7H2O

\,/ PnAot

co / PEG-400 NaOH/ PhMe g 5 o ,4 - B h

A breakthroughin biphasic, Rh(acrrt per(2,6- di-O -methyl)-p-cyclodextrin as an terminal double bonds are observed.

Phase-transfercatalysts

ride. rr.::.::r()nusing Cp*ReO, in the presence h:. ::r.'thodis potentially competitive with

Allylic phenyl sulfones undergo alkylation very readily when the c-Alkylations. anions are generatedin the presenceof aqueousNaOH and tetrabutylammonium bromide: with dibromoalkanes,cyclic products are obtained.r22,2-Dibromo-l-phenylcyclopropane and o-substituted phenylacetonitrilesreact to give cyclopropene derivatives.r3

CN

3 f ---i-o

,o+

+

Ph{

50% NaOH

\--/ \,/ B'AB,

"

Ph^

V

CH2Cl2 CllBnNEtsl+

,Ph

53%

450. I h

The PTC technique has been advantageouslyapplied to alkylationr4 and Pd-catalyzed arylationr5 of alkynes. For the Heck reaction, the proper selection of Pd, base, and PTC allows a reaction in water, aqueous/organic solvent mixture, or strictly anhydrous conditions.l6 In the presenceof 18-crown-6, concurrent cyclization and arylation is favored over the r? Heck reaction of a terminal double bond of alkenyl cyanoaceticesters. D..- .::lr methyl alkyl ethers-are oxidized is Thus, 2-adamantanone h . \ .rzrndines. fri

ll pru 6/t t-I.+ il995).

$"oot" -:. r IE.286-289 hr :': glvcol) [PEG] as a phase-transfer 1 :--r.redr from ArOK and CHrClr in oftriarylcyanurates: I :- ..-r'Jrna synthesis t\

j. the addition of alcohols to alkynes

ii:

:':cdomtnant. iJnBr. KOH and l8-crown-6 is highly

I :::

KH / l8-c-6 Pd(dppe)- PhBl 600, 19 h

with PEG as a PTC, Cor(CO)3 mediatesthe carbonylation anil hydroformylation. carbonylation of benzylic halides.r8A more complex system is used in the transformation of propargylic alcohols into 2-alkylidenesuccinic acids (9 examples, 84-97%o).teYery similar results are obtained from the carbonylation of alkynyl ketones'20

"^4,

N|(CN)2- LaCl3.7H2O

.r' $ithout solvent,5 synthesis of ] : .,irJes.6and the direct conversion of ::, ,rntedunderPTC. ' . , . methyl N-(methacryloYloxY)ethYl ti ::' i:ri presenceof BurNBr.8 \ \ : r :r iatalyzed by PEG-400' the reaction r'. _-

t l : : . : Jracy'ldisulfides,respectively.e'r0'Ihe ' ': polysorbate-80 as a PTC constitutes I -.

co / PEG-400 NaOH/ PhMe 9 5 o ,4 - 8 h

\

/cooH

+

1\ - / ;cooH phf\oor1

Phl-\-cooH (86 : 14) 95"k

A breakthrough in biphasic, Rh(acac)(CO)r-catalyzedhydroformylation is the use of per(2,6-di-o-methyl)-B-cyclodextrin as an inverse PTC.2I Highly selective reactions of terminal double bonds are observed.

26

Phase-transfercatalysts

Additions and condensations. Nitroalkanes form adducts with enones in aqueous media in the presenceof cetyltrimethylammonium chloride.22 Wittig reactions conducted in a solid (KOH)-liquid (CH2CI2) two-phase systema containing 18-crown-6 give rise to (E)-stilbenes as major products when one of the three phenyl substituentsof the phosphonium salt precursors is replaced with a chlorine atom. Both the lower steric demand of the Cl and a strongerP-Cl bond tend to shift the transition statetowa.rda nearly planar four-centered structure. Cycloadditions. Z-Yinylaziridines can be prepared directly from allyldimethylsulfonium bromide and N-sulfonylimines.2aThe sulfonium ylides are generatedin situ. A two-site PTC (l) preparedfrom acetophenone,formaldehyde, HCl, and triethylamine in three stepsis effective in promoting dichlorocyclopropanation.25It is of interest to note that l,1,2-tribromocyclopropane undergoes decomposition to give the diethyl acetal of propargylaldehyde under PTC in the presenceof an alcohol.26

Ph, 7-i,r,. =:1, .) EtsN + /

2Cl

(1)

Alcohols are oxidized in dichloroethane with catalytic amounts of a Oxidations. dichromate salt using sodium percarbonateas a recycling agent and P[C.2'7'28 Epoxidations of enones by sodium perborate2eor NaOCl30 under PTC conditions give high yields. However, with NaOCI and hexaethylguanidinium chloride, cyclohexenones give 6,6-dichloro-2,3-epoxycyclohexanones. The regenerationof carbonyl compounds from semicarbazonesby Me,SiCl-NaNQ3l also benefits from a PTC. rsalunkhe, M.M., Kavitake, B.P.,Patil,S.V.,Wadgaonkar, P.P."/CR(S.) 503(1995). 2Kavitake,B.P.,Patil,S.V.,Salunkhe, M.M., Wadgaonkar, P.P.BSCB104,675(lgg5). 3Bellucci, Chiappe, C.,Lo Moro,G. Sl, 880(1996). G., -Bessodes. M.. Boukarim. C. SL l119 (1996). 5Diez-Barra, E.,dela Hoz,A., Loupy,A., Sanchez-Migallon, A. JHC 31,l7l5 (lgg4). 6Durantini, E.N.,Chiacchiera, S.M.,Silber,I.J. SC 26,3849(1996). 7B.o*n. S.A..Rizzo.C.J.SC 26.4065(1996). 8Dubosclard-Gottardi, C.,Caubere, P.,Fort,Y. I51,2561 (1995). eWang, J.-X.,Cui,W., Hu, Y. SC25, 3573(lgg5). t\ilung, J.-X.,Wang,C.-H.,Cui,W., Hu, Y., Zhao,K.SC25,889(1995). rrMuiti, A.K., Bhauacharyya, P. IJC(B)358, 67 (1996). '.'Ionczyk, A., Radwan-Pytlewski, T. G L26,1ll (1996). ''Arct, J.,Fedorynski,M., Minksztym,K., Jonczyk,A. 1073(1996). S

-Dehmlow. E.V.. Fastabend,U. G lX. 5-1r l( '\guefack, J.-F.,Bolitt, V., Sinou, D. TLn. ^Jeffery, T. T 52, l0lI3 (1996).

Bouyssi, D., Coudanne,I., Uriot, H.. Gcrc. J 'Zucchi, C., Palyi, G., Galamb, V., Sampar-S r 1996). Zhou, 2., Alper, H. OM 15, 3282 (1996 t -..\rzoumanian, H., Jean,M., Nuel, D.. Cabr6 I :Monflier, 8., Tilloy, S., Fremy, G., Casurrr. --Ballini, R . , B o s i c a ,G . T L 3 7 , 8 0 2 7 ( 1 9 9 6 ' Bellucci, G., Chiappe, C., Lomoro. G. TL n t'Li, A.-H., Dai, L.-X., Hou, X.-L., Chen. \l . :'Bulukrirhnun, T., Jayachandran,J.P. SC L(. . :'Sydnes, L.K., Bakstad,E. ACS 50.4.16r lgq Mohand, S.A., Levina, A., Muzart, J. SC L t-BuMerSiH > > PhMerSiH, (EtO)3SiH,i-PrrSiH > > Ph3SiH'

n \ - r l

Pr3OSi

l r l

. \atrvi.C.,Valle'G JOC60'&16 (1995)' '1. (1994). -15.9451

a>

tsP13SiH

il r' It

273

I

r z \ z

t

I

l

etI a,si.^,si-z Il c v I 93%

(1) rt' 4h t the amine derivatives in the solid-phasc h: - . rr.'ferableto morPholine' :t:

n E,:

r.- and 1,7-enynesis catalyzedby ftCl. r '.ed.r

'Johnson, R.K. JOC59' 2287(1994)' C.R.,Raheja,

Poly-r1-(pyrazine)zinc borohydride. This reagent is prepared from the unstable Zn(BH)o by coordination Reiuctions,r compounds with pyrazine in ether. It is stableand efficiently reducesmany types oforganic rTamami, M.M. SC25,3089(1995)' B., Lakouraj, 296-297 Potassium /-butoxide. 13, 252-254; 15, 27 l-2'12; 17, 289-290; l8' involves l-alkynylphosphonatesr of synthesis one-pot A convenient Eliminations, t-BuoK. with elimination and p-keto phosphonates of enolphosphorylation

>a

'm E \ t\'l

97"/"

s

' . 1l 5 9 0 1 0 9 9 6 ) .

9 ? (Eto)2P.\_/\

NaH/ THF :

I

oPo(oE0r l

(EIO)2P.V^\ (EtO)2POCl

]

(EtO)rP\

-t*

90%(twosteps)

/

An ester group can be selectively hydrolyzed with Selectivesaponification.z at least one active r-BuoK in wet THF at 0o without affecting a malonate unit having methine hydrogen.

t-butoxide Potassium

EIOOC.

r / \./ .l_cooEt

Yt

l

AuOOC

COOET

I-BuOK/THF-H2O;

EIOOC. ,/\ t: / tl-COOX Y \'/

nuoo6

l.'u,**

Coot

7'1"/.

J.E.,Lee, C.W., Kwon. Y.. Oh. D \' . -.Hong, \\'ilk. B . K . s c 2 6 . 3 8 5 9( 1 9 9 6 r . 'Babler, J.H., Liptak, V.P., Phan.\. JOC 6l'Duhamel, P., Cahard,D., Poirier.J.-\l /C9 '\k-ryama, S., Tajima, K.. Nakatsulr.S . \r ,1995).

The I-BuOK-DMSO system is useful for inducing the condensation Atkynylation.3 of terminal alkynes with ketones to afford propargylic alcohols. De-O-sitylation.a Silyl dienol ethers are cleaved, and the dienolate anions can be trapped as dienol phosphatesand as Diels-Alder adductswith aldehydes'

I ,2\ //\

'/

v

)^oro,o.r, OSiMe3

Trofimov, B.A., Tarasuua.O.A.. Srgaltrr-\l

Potassiumcyanide. Retro-benzoincondcnsation-t K ketonesareobtainedb1 usrng rherefore,

a

.Ph

+ t-BuoK

Ph7'v HO

o

r*Cyanoalkylmethacrybtcs.: B rsters,a phasetransfercatalyst.methllt

860/"

of stilbenes.s With an excessof t-BuOK,stilbenesareconverted Dehydrogenation of air. A largerexcessof the basecauseshydroxylationat an into tolanesin the presence o-positionof thenitro group.It is essentialto useDMSO or DMF asa solvent'

MeO

Ph

MeO OMF (air)

\'liyashita, A., Suzuki, Y., Okumura- \' . lLr -Fort, Y., Dubosclard-Gottardi, C. SC 26. :t

fluoride.13,256-257:15.I Potassium KF is obtainedbr slor active Highly 100'.r Jryingat 1,3-Diolsfrom ft hydroxyacy kilar lsill I fl of phenyldimethl decomposition comt reactants that unveila pair of new

n

X=H,OH Rearrangement of O-propargyl ketoximes.b Treatment with theseoxime ethers into N-( I -alkenyl)acrylamides.

) pnA-ru'O

THF (DMSO)

\ o "n\^)t/ H 41%

t-BUOK

converts

o H o I tl )-\fsiu.ren | 6rH''.

As base.r KF on alumina eft-ct those derived from allylic alcohols r mchloroacetamides.Xanthatesare slml

Potassiumfluoride

f+: -

i

EIOOC. L/\ Y \./ t AuOOC

/ \4-COOH l COOH

71"k r r. -,.eiul for inducingthe condensation r..,.,l.ohols. .r. i.1. and the dienolateanions can bc d.:..-:. u ith aldehydes.

rHong,

275

J.E.,Lee, C.W., Kwon, Y., Oh, D.Y. SC 26,1563 (1996).

-wirk,B.K.sc26,38s9(1996). rBabler, N. JoC 61,416(1996). J.H.,Liptak,V.P.,Phan,

aDuhamel, P., Cahard, D., Poirier, J.-M. JCS(PI) 2509 (1993). 5Akiyuma, S., Tajima, K., Nakatsuji, S., Nakashima, K., Abiru, K., Watanabe, M. BCSJ 6E' 2043 (1995). hrofimov, B.A., Tarasuua,O.A., Sigalou,M.U., Mikhaleva, A.I. TL36,9181 (1995)'

Potassiumcyanide. Retro-benzoincondensation,t KCN promotesC-C bondcleavagein benzoins,and therefore,ketonesareobtainedby usingthis reactionin conjunctionwith prior alkylation.

I

f€.

'/,2'//\ \/ oPo(oE02

a'n

KCN/ DMF

Ph/\*.Pn

Ho ll o

\.YOH I

800,

t h

on'^'rr

Ph tl

o 98"/.

acyanoalkyl methacrylates.z By using KCN for displacement of the haloalkyl esters,a phasetransfer catalyst, methyltriphenylphosphonium, is added to advantage.

Ph 86"k

cr.. ,: r-BuOK, stilbenesare converted I ' ::c basecauseshydroxylation at an )\1i( ) i)r DMF as a solvent.

rMiyashita, T. CPBU,252(1996). Y., Higashino, A., Suzuki,Y., Okumura, rFo.t,Y., Dubosclard-Gottardi, C. SC26, 2811 (1996) Potassium fluoride. 13, 256-257; 15,2'12; 18, 29'l -298 Highly active KF is obtained by slow evaporation of a methanolic solution, followed by drying at 100'.r Desilylation of the acylsilanes and l,3-Diols from fthydroxyacylsilanes.z decomposition ofphenyldimethylsilyl fluoride to furnish a nucleophilic phenylating reagent unveil a pair of new reactantsthat combine to give 1,3-diols.

, r o H

I ::.rt nlent

with

o H o I tl

t-BUOK convens

KF / DMSO

{l\siur"zen ' coHrg

)

o

,n\*)tr' H 41./.

KF on alumina effects the formation of trichloroacetimino ethers, and those derived from allylic alcohols readily undergo rearrangement to afford N-allyl Xanthatesare similarly prepared.a trichloroacetamides. As base,3

Potassiumhydride

OH -t\./

ct3c-cN KF / Al2O3

?"'.

HruAo -\r,

?"'.

2oo

HttAo

--------t

48h

^/ 85%

Amides from nitriles.s This hydration is catalyzed by KF on natural phosphateand sodium phosphatedodecahydrate.It is done in refluxing butanol (3 examples,90-987o). rSmyth, T.P.,Carey,A., Hodnett, B.K. f 51,6363. 'Morihata, K., Horiuchi,Y., Taniguchi, M., Oshima,K., Utimoto,K. TL36,5555(1995). 3vill"-in, D., Hachemi,M. SC 26, l32g O996\. avill.rnin, D., Hachemi, M. SC26, 2449(l9g6t. ss"bti, S.,Rhilil,A., Saber,A., Hanafi,N. TL37,6555(tgg6).

Potassium hexamethyldisilazide. 13, 257: 16, 282-283; 18, 298-299 Cyclizntionofalkylo-(1-alkynyl)arylketones. The formation of a 3-alkyl-lnaphthol on treatment of the ketone (6 examples, 10-95%o)with KHMD, initially at a lo* temperature,involves a rather unusual intramolecular addition of an enolateion to an alkyne without any activator directly attached.

CoHtg

rMak

PhMe -78o-> 8oo

Z\r\ t i

I

l

\."\-Z\.

'Mohri,K., Suzuki,K., Usui,M., Isobe. K .T :Rigby, J.H.,deSainteClaire,V., CuisiarS\ 'El-Khoury, M., Wang,Q.,Schlosser. \l Il .

Potassium monoperoxysulfate. 13. l-rt

\-\,r.COOMe 7Oo/"

cleavageofs-cbonds. Benzyloxymethyl 2-pyndyl sulfone can be used to benzyloxymethylate carbonyl compounds to afford RR'c(oH)cHroBn (g examples, 75-91vo).22 Aryl thiocyanates suffer loss of the cN group. The thiolate anions can be alkylated in situ23or coupled with aryl iodides in aPd-catalyzedprocessfor the preparation of unsymmetrical diaryl sulfides.2a Reductive couplings. cx,-Keto amides furnish tartaric amides,25 and the dimethylacetals of aromatic aldehydes under anhydrous conditions give a.,a.'dimethoxybibenzyls.26In the presenceof water, demethoxylation occurs. When the acetals

Expansion of cy clobutanones. expansionto furnishcyclopentanorrs Tetrahydrofurans."' c-Iodoalt reactionwith SmI, in an ethylenearrm osiEts ph'1,,/\,

+

CFr2-{rl

Reductive alkylation. In a svnrb two acetaldehydechains in the maskcd by reductive alkylation of N,N dibcru reactionis mediatedby SmI,-LiCl.

contain electron-withdrawing groups (cN, CooR) in the aromatic nuclei, the reaction products are ATCHTOMe; acetalsof aliphatic aldehydesbehave similarly. Acid chlorides give cl-ketols as coupling products exhemely rapidly on treatment with SmI, in the presenceof t-BuNC and NiI2.27 2-Arylcyclopropane-1,1-dicarboxylic esters undergo ring-opening coupling to give 3,4-diaryl- I , 1,6,6-hexanetetracarboxylicesters28 in moderateto good yields on heating with SmI, in THF. y-Hydroxy amides. Acrylamides undergo reduction by SmI, and in the presenceof

Sml2 - Liq

carbonyl compoundscondensationfollows. This method can be usedfor preparing 6-amino alcohols when it is applied to N,N-dibenzylacrylamide.2e

o an2Nry

Sml2/ THF > cyclohexanone

-=

Bn2N

HzN /Y) "o'\,,'

Et2AlCl/ I-BUOH 750/o

Ene reactions.3O SmI, is a remarkable ene reaction catalyst that promotes the cyclization of some unsaturatedaldehydesand of alkylidenemalonatesat room temperature. 7-Aza-1,3-dienes.3t Imines react in the presence of aldehydes and SmIr. The reaction is essentially an aldol condensation in which the imines behave as the enamine

Reductive coupling of p-hydroxl a anti-4,6-dihy droxyalkanenitrilesonlr .r! r is responsiblefor the results.

tautomers.

O'\/\

* ,/..tc'o

S m l 2/ T H F

,,-Yl'*-,"\,,^\

oHo

,^^4&

I

2

THF. 0

SamariumfiD iodide

BnN

I

\-\,cooMe 70"/"

p.::.lrl sulfone can be used to RR'CrOH)CH'OBn (8 examples, r: .rr. The thiolate anions can be rr.:. r /ed processfor the preparation r.rrtaric amides,zs and the I llr.irrrus conditions give c,o'h r.. ..rtionoccurs.When the acetals

Expansionof cyclobutanones. With CH2I2 and SmI, cyclobutanones undergo expansion to furnish cyclopentanones.32 Tetrahydrofurans." o-Iodoalkyl trialkylsilyl ethers undergo a very unusual reaction with SmI, in an ethylene atmosphere. osiE13 +

phl/\,,At

CFi2=CH2

Sml2 / THF

phl^/\o2"",lpn 640/o

Reductive alkylation. In a synthesisof meso-chimonanthineandmeso-calycanthine, two acetaldehydechains in the masked form are introduced as a (z)-2-buten-l,4-diyl unit by reductive alkylation of N,Nldibenzylisoindigo with (Z)-1,4-dichloro-2-butene.3aThe reaction is mediated by SmIr-LiCl.

n ::r rr0matic nuclei, the reaction s \':r.1\e similarly. ir::::nclt' rapidly on treatmentwith Sml2 - LiCl

:rnr-opening coupling to give !':.,:r to goodyieldson heatingwith g

clJ

Lcl

r: : .r SmI", and in the presenceof rt,- .,:rhc usedfor preparing 6-amino

mescchimonanthine Horc

-=

J

H2o

n'*A/)ll Hov mesocalycanthine

!4-::,'n catalyst that promotes the dE':i:rrlonates at room temperature. n.: ,'t aldehydes and SmIr. The ::: rnrinesbehaveas the enamine

-\a'N,^:,/\

Reductive coupling of B-hydroxy aldehydes and ketones with acrylonitrile leads to anti-4,6-dihydroxyalkanenitriles only.35Chelation control in the formation of ketyl radicals is responsiblefor the results.

Ph

'

oHO

"l JY{ "/

Sml2

AcN THF - MeOH 0

296

Samarium(Il)iodide-hexamethylphosphorictriamide

S-

cyclic l,2-amino alcohols.36 Intramolecular reductive coupling of carbonyltethered oxime ethers with smr, forms the cyclic products even in the absence of HMpA. only one diastereomer is produced. After water has been added (20-25 equiv), the N-o bond is cleaved in a subsequent reduction with the excess reagent at room temperature. A previous report indicates the failure of the intermolecular

A tandem process transforming lacto diquinanes3is both remarkable and effioco

version.

IHamann, B., Namy, J.-L., Kagan,H.B. T 52,14225(1996);Machrouhi,F., Hamann,B., Namy, J._L., Kagan, H.B. SZ 633 (1996). ^'Ha, D.-C., Yun, C.-S., Yu,E. TL37,257't (tgg6\. rYing, T., Bao, W., Zhwrg,y ., Xu,W . TL 37,3g85 (1996). -Arime, T., Takahashi, H., Kobayashi, S., yamaguchi, S., Mori, N. SC 25, 389 (1995). sAoyagi, Y., Yoshimura, M., Tsuda, M., Tsuchibuchi, T., Kawamata, S., Tateno, H., Asano, K.. H., Obokata,M., Ohta, A., Kodama,y. JCS(?I) 699 (1995). -Nakmura, 6Yoshida, M., Suzuki, D., Iyoda, M. SC 26,ZSZ3 (1996). 'Park. H . S . .L e e . I . S . .K i m . y . H . T L 3 6 , l 6 i 3 ( l g g 5 t . outimoto, K., Matsui, T., Takai, T., Matsubara,S. Ca 197 (1995). D.. Skrydstrup,T., Beau,J.-M. ACIEEJ\909 (1995). ,'Mazeas, '"Urban, D.. Skrydstrup,T.. Riche, C., Chiaroni,A., Beau,J._M. CC lgg3 (1996). "Hung, S.-C.,Wong, C.-H. ACIEE35,267l (1996). '"Aurrecoechea, J.M., Solay,M. TL36,2501 (1995). ''Goulaouic-Dubois, C., Hesse,M. TL36,7427 ,lggjD. raBenati, L., Montevecchi,P.C., Nanni, D., Spagnolo,p., Volta, M. TL36,7313 (1995). '-Huang. Y . , Z h a n g ,Y . , W a n g . Y . S C 2 6 . 2 9 l l t t 9 9 q . 'oKeck, G.E., McHardy. S.F.,Wager,T.T. TL36,'741g (lgg5). "Chiara. J.L.. Destabei.C.. Gallego,p., Marco-Conrelles,J. ,/OC 61, 359 (1996). 'oGoulaouic-Dubois. C., Guggisberg,A., Hesse,M. JOC fi,5969 (1gg5). ''Molander. G.A.. Stengel.P.l. JOC 60.6660 ( t995). '"Van d e W e g h e .P . .C o l l i n .J . i " L J 6 . I 6 4 9 ( 1 9 9 5 ) . -'Aurrecoechea, J.M., Femandez-Acebes, A. SL 39 (1996). "Skrydstrup, T., Jespersen, T., Beau,J.-M., Bols, M. CC5l5 (1996). "Toste, F.D., LaRonde,F., Still, I.W.J. TL36,2g4g (1gg5). '*Still, I.W.J., Tosre,F.D. JOC 6t, j67j (1996). "Yamashita, M.. Okuyama.K., Kawasaki,I., Ohta, S. TL37,7.755 (1996). '"Studer. A., Curran,D.P. ^tL 255 ( 1996). 2tHurnunn. B., Namy, J.L., Kagan,H.B. T 52, 14225(1996). "Yamashita. M., Okuyama, K., Ohhara, T., Kawasaki, 1., Ohta, S. SL 547 (1996). "-Aoyagi, Y.. Maeda,M.. Moro, A., Kubota,K., Fujii, y., Fukaya,H., Ohta,A. CpB 44, l8l2 (1996). -"Sarkar. T . K . . N a n d y .S . K . f L 3 7 . 5 t 9 5 ( 1 9 9 6 ) . ''Shiraishi, H., Kawasaki,Y., Sakaguchi,S., Nishiyama,y., Ishii, y. TL37,72gt (1996.). '"Fukuzawa, S., Tsuchimoto,T. TL36,5937 (1995). "Hojo. M.. Aihara, H., Hosomi. A. JACS ll8. 3533 ( 1996). '-Link, J.T.. Overman.L.E. JACS l 18. 8 I66 ( t996). 35Kawatsura, M., Hosaka, K., Matsuda, F., Shirahama,H. SL jlg (lgg5). 'ochiara, J.L., Marco-Contelles, J., Khiar, N., Gallego, p., Destabel, C., Bernabe, M. JOC 60. 6010 ( 1 9 9 5) .

Samarium(Il) iodide-hexamethylphosphoric triamide. Barbier reaction.t The reaction between aryl halides and ketones using SmI2-HMPA is reported.rIodoalkynesafford propargylic alcohols in an analogous reaction.2

s"r1 'l

:'

1

The product from an intramolecular rE cyclopentaneunit when an unsaturatedcarb group.4 (Compare the group transfer bromoalkylidenecyclopentanes.)5

:L

T}

Reductiveaddition of carbonyl n ht havebeentransformedinto cyclopentano thesusceptible 5-pentenals.

'\^ / ",, rco,','\ lotc AcO

Sml2

,

THF - HMPA A

When the double bond is conjugated ro i intermolecular version is also valuable for ri

9ntr THF.I{

Samarium(Il)iodide-hexamethylphosphorictriamide 297 ' :-.Ju.tive coupling of carbonyln L.-- r\ even in the absenceof HMPA. s *-'rn added (20-25 equiv), the N-O

A tandem process transforming lactones bearing haloalkyl chains into substituted diquinanes3is both remarkable and efficient.

c\,l.\ reagentat room temperature.A r . . -. r : \ e r s i o n . Sml2 - THF

i \1 ,.:rouhi,F.,Hamann, B., Namy,J.-L.,

HMPA oo -> rt 4 h

\ S C 2 5 , 3 8(91 9 9 5 ) . \1 f :,.,.r.imata, S., Tateno,H., Asano,K., '. .., 1995).

960/"

The product from an intramolecular reaction of a 6-bromo ester can form a second cyclopentaneunit when an unsaturatedcarbon is provided to couple with an emerging ketyl group.4 (Compare the group transfer reaction of 6-bromoalkynes to furnish

:u

bromoalkylidenecyclopentanes. )5 l J . i

, \ t { ' C 1 8 8 3( 1 9 9 6 ) .

\t rL 36,7313(1995).

Sml2

TBSO,.,

THF - HMPA

|v.

Oo-> rt

61.-r_s9 0996). . ' , ,1 9 9 5 ) .

I I

t

Reductive addition ofcarbonylto double bond. Some carbohydrate derivatives have been transformed into cyclopentanolsbvia fragmentation with SmIr, which provides the susceptible5-pentenals.

rrrfi r.

,,

l-

--r
ff

PhH A

v fo)')

'Jufiu,M.,Uguen, (lgg5). D.,Zhang,D. AJC 48,2'7g Sodium-ammonia.16,303-304;18,324 Birch reductions. Derivativesofpyrrolerandfuran2arereducedto thedihydrolevel. openingup manysynthetic possibilities.

Na/NH3i Mel

/cooH

Na/ NH3 FProH / NH4CI

(\,,"".

A+rl r\ \6

cH2N2

Tetrazoles.3 Ketones are con\cftc tbllowingequation

Sicll - NaL3

NJ

Boc $

,cooMe siMe3

Aryldemethyhtion of ArSnMe3 The replacementof one or all of the methyl groups attachedto tin can be achieved via cleavageof the Sn-Me bond followed by photoinduced S*1 reaction with chloroarenes.3

l*t

Ph

MeCN. 2f

Ko, S.Y. JOC ffi,62s0 (1995). -Couladouros, E.A., Apostolopoulos, C.D. 5L 3 'El-Ahl, A.-A.S., Elmorsy, S.S.,Soliman. H.. t

Sodiumborohydride.13,278-279: lS. 2 syn-1,3-Diok.' The reduction of stereoselective by precoordination of thc r

Sodium borohydride

\. lL 36.4307(1995). r 1 g< : : , , 1 9 9 5 ) .

;'\r-snMe.

u"o)-)

clli-\

*

Na/ NHg't-BuoH;

-_ ; .b"

9or"

t"-ri'\

ft\Y/

9o""

u.ol.) 890/"

t : : 17.314;18,322-323 T:.r .iddition of alcohols to the esters !o [ \\:rlc this reaction is suitable for thc o\ .:..:ranc esters,unsymmetricalalkynoic

11:.rrh\l sulfones undergo C-S bond n l::r. reaction can be used to preparE

'.'eo

Donohoe,T.J.,Guyo,P.M. JOC 6L,7664(1996). tB"ddo".,R.L.,Lewis,M.L.,Gilbert,P., S.P.,Wang,S.,Mills, K.TL37'9119 Quayle,P.,Thompson' r 1996). 'Yammal, J.C.,Rossi,R.A.JOMC 509,I (1996). C.C.,Podesta,

Sodium azide. 18, 325-326 l,2-Diol thionocarbonatesbehave in a manner similar to that of ftAzido alcohols.r rheir corresponding cyclic sulfates, and their reaction with Naltt in DMF leads to B-azido alcohols. Amino acids.z Hydrazoic acid generated in situ from NaN, and HOAc adds to y-keto-o,p-unsaturatedcarbonyls.

O. 9Me /\-_J

O /\

^(-r) ff

79'/"

"V

r.> fl

u1'^) "r

NaN3 - HOAC

NHz

2oo

940k

Tetrazoles.3

Ketones are converted into substituted tetrazoles, as depicted in the

following equation.

:\, | X-.N-L

)

N t l Boc 6

:

F\ \6

P/-

SiCl4 - NaN3 MoCN, 25o

N-\

ll

'N

-,^N Ph

-.

l

N-N. N l

tn''-il*

87"k

85'/"

li-.

o

,,cooMe siM"3

groups f ..:-J:r)eDtof one or all of the methyl 'r.-: :r-Me bond followed by photoinduced

'Ko,s.Y.Joc ffi,6250(1995). rCouladouros, C.D.SL34l (1996). 8.A.,Apostolopoulos, 3El-Ahl, (1995). H.,Amer,F.A.TL36,733'/ Elmorsy, S.S., Soliman, A.-A.S.,

Sodiumborohydride. 13,278-27 9; 15, 290;16,304; 18' 326-327 syn-1,3-Diols,' The reduction of B-hydroxy ketones with NaBHo is highly acid. with terphenylboronic of the substrates by precoordination stereoselective

308

Sodiumborohydride

Reductionof hinderedketones.2 The addition of Amberlyst-l5 (in the H* formr resin to the reducing system in THF permits the reduction of hindered ketones. other functionalities, such as acetalsor silyl ethers,remain unaffected.

reduction of enones has been reported prerr

Regioselectivereductions.' The deoxygenation of o-hydroxyphenones can bc accomplished. Thus, mixed carbonates of 4-acylresorcinols are converted into monoprotectedalkylresorcinols.

rccomplished

OCOOMe

NaBH4

'A

f-o"oor" _..\O

; 76"/0

RCOOH -+ RCHzOH. On conversion into the N-acylimidazole, a carboxylic acid becomesreducible to the primary alcohol by NaBH, in the presenceof water.a Reduction of C:N bonds, A convenient preparation of camphorsultam involves the treatment of lO-camphorsulfonyl chloride with ammonia, followed by reduction with NaBH4.5 3-exo-aminoisoborneol is available from 3-oximinocamphor by a two-step reduction process,bfirst with NaBH4 alone and then with NaBH4-NiCI2.6H2O.

ct.B-unsaturated esters, amides, and nirnbs Other reactions. The deoxygenauoo ,in EIOH, 2h,83Vo yield)l2 and the con\rrrx using NaBHo as reagenr, .{ml

nith NaBH,-(NH/2SO4.

tYamashita, H., Narasaka,K. Ca 539 ( I 996 , -Caycho, J.R., Tellado, F.G., de Armas. p.. Teib 'Milchell, D., Doecke,C.W., Hay, L.A.. Krrorg. tshu.-u, R., Voynov, G.H., Ovaska. T.\' . \t rq Capet,M., David, F., Bertin, L., Hardr. J C SC "hzeslawski. R.M.. Newman. S., Thornron.E R Sclafani,J.A., Maranto,M.T., Sisk. T.:\1..\ ar: ; 'Bhattacharyya, S. SC 25, 206l (lcqsl 'D'Silva, C., Iqbal, R. S 457 (1996). 'Krein, D.M., Sullivan,P.J.,Turnbull. K. TL S1. 'Sim, T.B., Yoon, N.M. SL :/26(1995t. -McAlonan, H., Stevenson,P.J. OM 14. {O: | , l{ 'At-Abed, Y., Naz, N., Khan, K.M.. Voelrcr_\r ''Gohain, S., Prajapari,D., Sandhu.J.S. Ca -:< , l

Sodium borohydride-antimony(trI I hrf,d Hydrodebrominatinn.' Remor.al of r low temperaturesis accomplished* ith \aBl ArNOz -->ArNHz.2 This reductioo c

r+.r -Y ,t LS=n

o

rA MeOH - H2O

\

l'" -"=o o 660k

NaBHo-BiCl, at room temperature. 'Suyama, S.,Inamura, Y. CL633(lc).gf4. -Ren, P.-D.,Pan,S.-F.,Dong,T.-W.,Wu. S -H 9

Sodium borohydride-bismuth(Ill) chltrid Reduction ofdouble bonds. Thrs rot bondsin suchcompoundsas styrenerandcl!

Reductive alkylation of amines. Selective benzylation of terminal amino groups of a polyamineTis achieved by NaBHo reduction of the derived Schiff bases. Secondary amines are methylated on treatment with paraformaldehyde, ZnCl, and NaBHo in dichloromethane(19 examples,60-96Vo).8Note the unusualsolventused.

rRen, P.-D.,Pan,S.-F.,Dong,T.-W.,Wu. S.-H 5( -Ren, P.-D.,Pan,S.-F.,Dong,T.-W.,Wu. S.-H j{

N-Aroylpynoles are deoxygenatedby NaBHr-BF..OEtr.e Apparently, this is a borane reduction. More interesting is the transformation of aroyl azides into N,N-bis(2,2,2trifluoroethyl)anilines (with NaBH,-CF,COOH),'0 which proceeds by a Curtius rearrangementfollowed by trifluoroacetylation and reduction.

Sodium borohydride-iodine. 17, 316: lt. Reduction of C:N and N:N bon&. aminesl and of both azoarenes and azorr

Conjugate reductions,tr Borohydride exchange resin with catalytic amounts of CuSOo constitutes a valuable reagent for the saturation of the conjugated double bond of

achieved.

P. SC25,3503(1995, ln-U.y, D., Champagne, -Karmakar, D., Prajapati,D., Sandhu,J.S."/CR,S,r

Sodium borohydride-iodine

r. :r ,t .\mberlyst-15 (in the H* formr I ::.rirition of hindered ketones.Othcl ir. -:..rtiected. ir: --. Lrf o-hydroxyphenones can ba l-,, ..rerorcinols are converted into

a.B-unsaturatedesters,amides, and nitriles in methanol at room temperature.The similar reduction of enoneshas been reported previously. Other reactions. The deoxygenationofbis(tributyltin)oxide to afford hexabutylditin , in EIOH, 2h,837ayield)12and the conversion of N-alkenylpyridinium saltsto ketonesr3are .iccomplishedusing NaBHo as reagent.Anilines are obtained by reduction of nitroarenesta sith NaBH*-(NH/2SO4.

OCOOMe

/\ I '-:tnon ) 76"/"

:: : \ -acylimidazole,a carboxylic acid { . ::: :ne presenceof water,o ni:.1:.ltion of camphorsultaminvolves h i:rr::r(rnia.followed by reductionwith r- i ,,riminocamphor by a two-step n .' ::r \aBHr-NiCl2'6H2O.

a,',_

:Yamashita, K. CL 539(1996). H., Narasaka, :Caycho,J.R.,Tellado,F.G.,de Armas,P.,Tellado,J.J.M.24 38, 277 (199'7). 'Mitchell, D., Doecke,C.W.,Hay,L.A., Koenig,T.M.,wirth, DD. TL36' 5335(1995). tsharma, Voynov,G.H.,Ovaska, V.E. SL 839(1995). T.V.,Marquez, R., iCapet,M., David,F., Bertin,L., Hardy,J.C.SC 25,3323(1995). ^Przeslawski, Joullie,M.M SC25' 29'75(1995). S.,Thomton,8.R., -Sclafani. R.M..Newman, J.A..Maranto,M.T., Sisk,T.M., Van Arman,S.A. JOC 6l'3221 0996). 'Bhattacharyya, S. SC25,2061(1995). 'D'Siluu, Iqbal,R. s 457(1996). C., "Krein,D.M.,Sullivan,P.J.,Tumbull,K. TL37,'7213(1996). 'Si-. T.8.. Yoon.N.M. 5L726(19951. ' :M.Alonun,H., Stevenson, P.J.OM 14, 4021(1995). 'tAl-Abed,Y., Naz,N., Khan,K.M., voelter,w. ACIEE 35, 523(1996). 'tcohain,S.,Prajapati, D., Sandhu, I.S. CL725(1995).

halide. Sodium borohydride-antimony(Ilf Removal of the halogen atom from an o-halo carbonyl at Hydrodehrominatian.' low temperaturesis accomplishedwith NaBHo-SbBtr. This reduction can be performed with either NaBHo-SbCl., or ArNOz -+ArNHz.' NaBHo-BiCl, at room temperature. 'Suyama,S.,Inamura,Y . CL 633(1996). :Ren,P.-D.,Pan,S.-F.,Dong,T.-W.,Wu, S.-H.SC 25,3799(1995).

-S=n

66'/.

' . Lrrion of terminal amino groups of - :r r ed Schiff bases. ...:rh paraformaldehyde, ZnCl, and \, 'te the unusualsolventused. ( )Et..eApparently,this is a borane : .rroyl azides into N,N-bis(2,2,2u hich proceeds by a Curtius - l . r ter o n . :: resin with catalytic amounts of r ,rf the conjugated double bond of

chloride. 18, 327 Sodium borohydride-bismuth(Ilf Reduction ofdouble bonds. This reducing system is capable of saturating double esters'2 bondsin such compoundsas styrenelando,B-unsaturated rRen,P.-D.,Pan,S.-F.,Dong,T.-W.,Wu, S.-H.SC 26,763(1996). rRen,P.-D.,Pan,S.-F.,Dong,T.-W.,Wu, S.-H.SC 25,3395(1995).

Sodium borohydride-iodine. 17, 316; 18, 328 Reduction of C:N and N:N bonds. The reduction of O-acyl oximes to primary aminesr and of both azoarenes and azoxyarenes to N,N-diarylhydrazines2 is readily achieved. P. SC25,3503(1995). ln*U.y, D., Champagne, 'Karmakar, D., Prajapati,D., Sandhu,J.S../CR(S)464(1996).

310

Sodiumcyanoborohydride

Sodium cyanoborohydride. 14, 287-288;16, 305-306; 18, 331 Nitroalkanesfromnitroalkenes.l The reduction of the conjugated double bond with NaBH,CN is catalyzed by a zeolite (H-ZSM-s) in MeOH at room temperature (10 examples, 65-79Vo). Reductive alkylation. Alkylation of an amine simply involves heatment with an aldehydein the presenceoftrimethyl orthoformate as a dehydrant and in situ reduction.2An analogous method applying to d-amino esters with glyoxal results in optically active N,N'-disubstituted piperazines.3and a convergent reductive amination of a ketodialdehyde to form an indolizidine skeleton tn 53Vo yield makes possible a concise synthesis of castanospenninefrom cr-D-glucopyranoside.a

-,"ro

Ea)

r"o',,'( and-

\- ^i '', / Bno,,"( )

HCOONH4

NaBH3CN MeOH

6en

H. BnO

:

by chain homologation based on alkylation of benzothiazol-2-yl methallyl sulfone.5 Transposition of the double bond occurs during the desulfonylation.

N NaBH3CN

\

aq HCI / THF

\

Ph

H

a^'l't l

Ogn

Desulfunylation. The facile detachment of the arenesulfonyl moiety from allylic benzothiazol-2-yl sulfoneswith the use of NaBHTCN is crucial to the preparationof alkenes

\-so,

said to be cleaved with this reagcr rdvantage over existing procedurer Reductiv e dealkoxylation ol rt

H2 Pdlc

mine

S , X

Sodium cyanoborohydride-boroa De-O-protection. Both tetrah

ethersthat retain the larger alkvl gro

Bno-r1o r

2 h

85'/"

Cleavage of enol ethers. The combination of TBAF and an acid such as BF,'OEtt is .elective for the deprotection of enol ethers.r0In the presenceof an acid fluoride, such an enolateion can be O-acylated with retention of configuration.rr

98"/.

\

b.

Cl . ,f

F

r"oSo"

H2O2-KHCO3/ MeOH

OH

A

321

,r..

PSiMe3

BuaNF - C15H31COF

THF.d.

30 -76%

Cl

n n \,/ \,/ \-/

.OCOC15H31

2h u"k

leading to a perhydroindanolone ir :n that flanks the departing silyl groq

Itl s

-K Yi

MeOOC rg

- =-78o -

ff:

-

.J-t

w

oH rr,t"ooS

'Ce*era, M., Marquet,J. TL37,'7591 (1996) rHanessian, Devasthale,P.Y. TL37,987 (1996). S., 'U.ki, M., Nishigaki,N., Aoki, H., Tsurusaki,T.' Katoh' T. CL'721 (1993)' rJonczyk, A., Kaczmarczyk,G. TL 37, 4085 ( I 996). 5cui, J., Ne.oto, H., Nakamura,H', Singaram'B., Yamamoto,Y ' CL'791 (1996)' 6Capperucci,A., Degl'Innocenti, A., Leriverend, C., Metzner, P ' JOC 61,7174 ( 1996)' ts.hinr"t, D., Blume, T., Jones,P.G' ACLEESS'2500 (1996)' sHarmata, M., Jones,D.E. TL36,4'169 (1995). 'suginome, M., Matsunaga,S.1., Ito, Y. SL 941 ( 1995). "'Gevo.gyan,V., Yamamoto,Y. TL36,'1765 (1995). : r L i m a t ,D . , S c h l o s s e M r, . 251,5799 (1995).

u"/"

^ro av

. '..r\ts of the silylmethylation of [ ::.:rmentationinducedbY TBAF'

Tetrabutylammonium hexanitrocerate. y-Keto esters.t Radicals derived from cr-tributylstannylaceticesters are formed by oxidation with the cerateion. They react with electron-rich alkenes,such as silyl enol ethers under the formation of Y-keto esters. :Kohno,Y., Narasaka, K. BCS,I68,322(1995).

\

siMe3 &raNF / THF ; + KOH

4# t t

l \,^NHz 69%

Tetrabutylammonium nitrate. Th" preparation of RCHTONO, by the nucleophilic substitution of Alkyl nitrates.t -92Vo)' alkyl toluenesulfonatesby sodium nitrate is catalyzedby BuoNNO, (7 examples,67 rHwu,J.R.,Vyas,K.A.,Patel,H.V.,Lin, C.-H.,Yang'J.-C.S 4'11(1994)'

322

Tetrachlorophthalicanhydride

Tetrabutylammonium

peroxydisulfate.

Oxi.datinns. This reagent is able to cleave tosylhydrazones in good yields (18 examples,90-987o)r in refluxing dichloroethane.Oxidation of sulfides to sulfoxides occurs at room temperature(11 examp"les,98-99.5Vo).2 Tetrahydropyranylethers.'

Alcohols in refluxing tetrahydropyran (not dihydropyran) form THP ethers in the presenceof the ammonium persulfate (9 examples, 86-95Va). Oxidation of the cyclic ether precipitatesthe reaction. rchen, F., Yang,J., Zhang,H.,Guan, C.,Wan,J. SC25,3163(1995). 'Chen,F., Wan, J.,Guan,C., Zhang,H.SC 26,253(1996). 3choi,H.c., cho, K.L, Kim, y.H sL207 oggs\.

the cleavageconditions involving ethl lencd is insolublein commonly used solvenrsrCH and therefore can be removed by filtratron

rDebenham, J.S.,Fraser-Reid, B. "/OC61.{-r: , l9

Tetrachlorosilane. Trichlorosilyl enol ethers.t The rea: resultsin trichlorosilyl analogs that are hrght catalysts.Asymmetric synthesisin rhe prescr

lDenmark, S.E.,Winter,S.B.D.,Su,X.. $ ooe.X . Tetrabutylammonium

polyoxotungstates.

Carbonylation' Homologous aldehydes are formed as the major products from alkanes under radical carbonylation conditions. Thus, magnetically stirred acetonitrile solutions of BuoN+(W,oOrr)a-or BuoN+(PW,rOao)3-and alkanes are saturatedwith CO (l atm) and are irradiated (550-W medium-pressure Hg lamp and a Pyrex filter) at room temperaturefor 16 hours to complete the reaction.

Tetracyanoethylene (TCNE).

Acetonidesfrom epoxides.t TC\E .z C-O bond of an epoxide. On the other han< rearrangementto give carbonyl produa_s Th of the substratesis required.

lJaynes, B.S.,Hill, C.L.JACS117,4704(1gg5).

(triphenyl)difl uorosilicate (TBAT). The reagent BuoN+Ph,Si$ is prepared in two steps (95Vo yieldl from Ph,SiOH by treatmentwith aqueousHF in methanol and then with TBAF in a mixture of THF and dichloromethane.It is a good sourceof fluoride for nucleophilic substitution of alkyl sulfonates.Alkyl halides undergo elimination preferentially. Tetrabutylammonium

o

NC,

\,/.oPh -

N/

AlkylJluorides.t

;""^

,cN t""

--'-'/' "/

^

750/o

Alcoholysis of epoxides.z Eporrde og I.l-diols is promotedby TCNE ar room remp

o--\,^

{ i I

,CooMe

l " o r f

Propargylalcohols,'

BuaN* Ph3SiF5

o\"/r''cooMe \ t

. i :

MeCN

n d i

4.48h

760/"

The condensationofalkynylsilanes and carbonyl compounds

is mediated by TBAT. tPilche.,A.S., Ammon,H.L.,DeShong, P. JACS117,5166(lgg5). 2Pil.h".,A.S.,DeShong, P. JOC 61,6901(1996).

\tasaki,Y., Miura,T., Ochiai,M. CL t7 I 199.r '\lasaki, Y., Miura,T., Ochiai,M. ECSJ6'9.t95 , I

Tetraethylammonium formate. Monobenzylated Medrum's acids.' T \teldrum's acid with aromatic aldehrdcs a :c'rivatives. O.l

Tetrachlorophthalic anhydride. Amine protection.' The derived imides are stable to many reagents used in oligosaccharide transformations. Therefore, amino sugars protected as such imides arr useful synthetic intermediates.Ester groups and anomeric penten-4-yloxy residuessurvive

)-o 1 V /)-o

HCOONET4

Tetraethylammoniumformat€ 3n

lc;.: l,r*lhvdrazonesin good yields 0g F l\:Jation of sulfidesto sulfoxidesoccun t _

'..

retluxing tetrahydropyran (not r r iii' tmmonium persulfate(9 examples. h::. ::r' reaCtiOn. -:, Iq95).

tt l1-

the cleavage conditions involving ethylenediamine treatment. The by-product of cleavage is insoluble in commonly used solvents (cH2cr2, DMSO, DMF, EtoAc, Me,Co, MeoH) and therefore can be removed by filtration. rDebenham, ..1996\. J.S.,Fraser-Reid ,8. JOC 61,432 Tetrachlorosilane, Trichlorosilyl enol ethers.r The reaction of tributylstannyl enol ethers with SiClo results in trichlorosilyl analogs that are highly reactive as donors in aldol reactions without catalysts.Asymmetric synthesisin the presenceof chiral phosphoramidesis realized. rDenmark, S.8.,Winter,S.B.D.,Su,X., Wong,K.-T.JACSttt-, :,404(t9g6).

[\ ),

: rLrnled as the major products from l-.u.. magnetically stirred acetonitrile :nd alkanes are saturatedwith CO ( I

il.!::

iir iamp and a Pyrex filter) at room

5

:

)a

Tetracyanoethylene (TCNE). Acetonidesfrom epoxides.l

TCNE catalyzesthe insertion reaction of aceronelnto a c-o bond of an epoxide. on the other hand, it acts as a Lewis acid in MecN. inducing rearrangementto give carbonyl products. The presenceof an alkoxy group in a side chain of the substratesis required. NC, pN

crte ,TB.{T).

^/oPh

. preparedin two steps(95Vo yieldt trrr"-.r1r)land then with TBAF in a mixturc It'i : .:Lrndefor nucleophilicsubstitutionof X : l:r'tc'rentially.

NC

CN

S:F

NC, pN

j>.'.o"

NC

CN

.v.OPh M02CO

MeCN A 75"/"

84qo

Alcoholysis of epoxides.z Epoxide opening with alcohols to afford monoethers of 1,2-diols is promoted by TCNE at room temperature. F.-

O\u^r',COOMe \

l

f d i

rMasaki, Y., Miura,T., Ochiai,M. CL 17(tgg3). -Masaki, Y., Miura,T., Ochiai,M. ,BCSJ 69, 195fl996).

76/" f :. r.; nr lsilanesand carbonyl compounds

: '.

.e95).

.table to many reagents used in .rgars protected as such imides are trr, :--rc'ric penten-4-yloxyresiduessurvive :::

Tetraethylammonium formate. Monoben4ylated Meldrum's acids.t The salt is a catalyst for the condensation of Meldrum's acid with aromatic aldehydes and is a reducing agent for the benzylidene derivatives.

I

{-

o . , o '

Orl HCOONEt4

A".-/-or,,

ro o

n

Ar.

Or.. )-O

\ /V\ )-o

70 - 787"

324

Tetrakis(triphenylphosphine)palladium(0)

IToth,

G., Kijver, K.E. SC 25,3067 (lgg5).

Unsymmetrical I Suzuki coupling. ambient temperature in N.N{inrth Arylcyclopropanes are most amenablett a

Tetrahydro-2ll- 1,3-oxazin-2-ones. Reaction of these compounds with arylamines and arenethiols Aminopropylation.' 180" results in ring opening and loss ofcarbon dioxide. a solvent at about without

eO

rPoindexter, K.M. SC23, 1329(1993). G.S..Strauss,

Tetrakis(triphenylphosphine)palladium(0\. 16.31'7-323t 17.327 -331:18.347 -349

13, 289 -29 4; 14, 295 -299 ; 15, 300-304;

improvement of yields observed in some cases.

"v\

\t/

V

Br

(Ph3P)4Pd- PrhP -C-

THF, rr

OX,-.orcs

DMF , lod

C.H.r

Othercross-couplings.Ary'lation ligandhasbeen trom thetriarylphosphine

\ O H

(Ph3P)4Pd- LiCr

{-

(\^-B- v

\-

Amines are denuded of one or more allyl group(s) by the catalytic Deallylation.l transfer to barbituric acid, which is a known allyl group scavenger. A synthesisof (Z)-cinnamyl alcohols can exploit this coupling using Stille coupling. stannoxane derivatives.2 The coupling is favored by nitrobenzene as solvent, dramatic

$,.'u,,

availability of cyclopropylboronic acidr a

78%(Z: E 97: 3\

'

qol

. X

The Stille coupling between aryl halides and bis(tributylstannyl)ethyne furnishes symmetrical tolanes.3Dienyl triflones are available in three stepsfrom l-alkynes,a with the reaction sequenceterminated by a Stille coupling.

CoHrs

coHrs (Ph3P)4Pd

\_ ,' \ror"r,

-J

S nBu3

PhMe A

The coupling ofarylzinc halides*rth r

i-Arylindoles are obtained from 3-indoll l.,l-disubstinrtedbutadienesrlstans from I .{fter Pd(0)-catalyzedcoupling uith al\c Grignardreactionin the presenceof r Ph.P

SOzCF 93%

The cross-coupling of aryl triflates and halides in the presenceof hexamethylditin is a tandem process.sFrom pyridyl triflates, the formation of pyridylstannanesis implied.

--.--:

Cp2Zr(H"tCl THF,

PhS€

OO

40 min

(

)-ort EN

*

a'.-(

(Ph3P)4Pd- LiCl

Y_l

)

Me3Sn-SnMe3

1-W \:N

\---.7

dioxane

551"

A stereoselective approach to l.{dr tin-substitutedallylic halideswith alkenll The method is useful for synthesizine ctn

325 Tetrakis(triphenylphosphine)palladium(0) Unsymmetrical biaryls are prepared by Suzuki coupling6 at Suzukicoupling, ambient temperature in N,N-dimethylacetamide in the presence of TIOH. Arylcyclopropanes are most amenableto assemblyby a Suzuki coupling,T'8due to the ready availability of cyclopropylboronic acids and esters. f,.::

unds with arylamines and arenethiols

rF. : _::- Cu l )-'.-

f MF

CcHrr

':\

{"

I

ott

)

90"/.

o ,\o *-\--J

"u"{'

(PhsP)4Pd- CO PhMe, 5d

670/"

h:-

. rcmarkably easy to displace in the

{c, . -:r.tion. Benzamidesareproducedwhen r..:.::. .inrineunderCO.17

., . . . 1, E 9 : |.-2

'=G*

HO_,/

(PhP)4Pd - CO

I

y

I

K2CO3 / DMF

O.

,/,----i.

,XX\:-/X

O

f\ / /

p-/ v

|

600, 16 h

"n4"oo""

tqf 32"/.

'.rn-sof a cyclopropaneunit representsa

I

+

co

*

(^cooEt

OBz

(Ph3P)4Pd rt, l8h

62"/" An annulation of a 1-butyrolactone ring to naphthols23recruits co and an aldehyde to become the carbonyl group and the substituted o-carbon. Trifluoroacetic acid is a highly effective cocatalyst for this reaction, but HOAc, PhCOOH, and TsOH are not. The acid apparently promotes the formation of 2-(1-hydroxyalkyl)naphthols, which undergo carbonylation.That phenols are unreactive may be due to the difficulty in achieving this frst stepunder the conditions employed.

328

Tetrakis(triphenylphosphine)palladium(0)

Propargylic mesylatesare converted to the transposed2,3-alkadienoicestersand amides by (PhrP)oPdand CO in the presence of alcohols and arylamines, respectively.z These allenoic acid derivatives are precursors of butenolides. In a synthesis of kallolide-B, this reaction is the critical step; (PhrP)oPdis generatedin situ from (dba)rPd, and Ph,P in the

,siEts -OAc

*fOCOJ

cooire Na+

+

(

coorr€

presenceof carbon monoxide.25

3-Alkoxyallyl acetatesundergo subsdruoq

.{llylic alcohols and aminesbecome adequatcd of CO, and in the presenceof (PhrP).Pd. Umpolung substitutionsin which allllici' rr nucleophilesare realized in the presenceof dra kallolide-B

Intramolecular reaction initiated by ionization of an allylic acetateand participated in by a distal allene linkage can have different ramifications when the molecule is also equipped with another double bond.26The separationbetween this latter double bond and the allene moiety determinesthe structure of the final product.

(Ph3P)4Pd- CO

HOAc

AcO

>re"* 640k

8oo

=::;t

- CO (Ph3P)4Pd

OAc

HOAc 600

(Ph3P)4Pd- CO

HOAc 750

PhCHO

Y}

Rearrangements. Allylic sulfoximrrs r rhe tosylamides.32The reaction furnishes opti .ulfoximines. The rearrangement of propargyl dienyl ce method is useful for synthesizing retinal.

11

}f"oo'. \--\r'

r +

280/o

'2 "-/< ,\

.-{'.Vo

tek

(Ph3P)4Pd/ THF + 60o

o 22o/"

Allylic substintions. A notable exception to the general reactivity trend wherein carbonateis more reactive than acetatein the allylic substitution must be the consequence of a silicon effect.2lNote that both Pd(PPh,), and (dppe)rPd were employed.

Cycloadditions. An intramolecular p+ :r'clopropane unit and a conjugated ester prm :trrmalDiels-Alder reactionto rapidll'build q

Tetrakis(triphenylphosphine)palladium(0)

' 1-,- -posed 2,3-alkadienoicestersand amides c, : :. and arylamines, respectively.24These u:.:r'lrdes. In a synthesisof kallolide-B, this r::re J in situ from (dba)rPd, and PqP in the

1 a -

:

-

t

l

A $?OOCO--/

uOAc

+

Nat

-(

POOMe

(dppe)2Pd

COOMe

IHF, 5d

MeOOCOJ

/

J

SiEr3 cooMe \ / COOMe

3-Alkoxyallyl acetatesundergo substitution at the position 0 to the alkoxy group.28 under a moderatepressure Allylic alcohols and aminesbecome adequateallylating agents2e (PqP)4Pd. presence of in the of CO, and Umpolung substitutionsin which allylic3oor propargylic benzoates3lare converted into

lt """"t/

SiEt3

329

ll

nucleophiles are realized in the presenceof diethylzinc. 3 kallolide-B

rr: :. ,i an allylic acetateand participated in by rlt.,.:iirrnSwhen the moleculeis also equipped trr: .i:'cn this latter double bond and the allene

(Ph3P)4Pd - Et2Zn

BzO:*21 (,

+

PhcHo THF, rt, 7 h 760/"

-/;-

| --

Rearrangements. Allylic sulfoximines undergo Pd-catalyzedrearrangementto give The reaction furnishes optically active amine derivatives from chiral tosylamides.32 the sulfoximines. The reanangement of propargyl dienyl carbonates results in allenyl products.33The method is useful for synthesizing retinal'

Il

ffcoon \--\r'

2Ao/" (Ph3P)1Pd/ rHF>

^

cs,,^..,AcHo -

K4;*"*

60o

| ::

(36 : 64) 59%

22o/" I ro the general reactivity trend wherein t s : r lrc substitution must be the consequence ). ' .: dppe)rPdwere employed. '!

--

cycload.ditions. An intramolecular [2+3]-cycloaddition3a involving a methylenecyclopropane unit and a conjugated ester proceeds without stereochemicalscrambling. A formal Diels-Alder reaction to rapidly build up the skeleton of rebeccamycinis reported'35

330

J H

ind 9J.ll. 2,2,3,3-Tetramethoxybutane

Tetrakis(triphenylphosphine)palladium(0)

rh4arshall,J.A.,Wolf, M.A. JOC 61,3238( 1996, ' r5Marshall, J.A.,Wallace,E.M., Coan,P.S."fOCO.

A., Nakanishi,S.,Yanrarrrro f., Yanagisawa, lpoi, ''Thorimbert,S.,Malacria, M. TL37,8483( 1996' :8vica.t,N.,Cazes, B.,Gore,J.TL96,535(l99Jr resukamoto, M., Shimizu,I., Yamamoto,A,.BCSJgt lolu-u-, Y., Tanaka,A., Yasui,K., Goto,S..Tanrl slTu-u-, Y., Goto,S.,Tanaka,A., Shimizu.\t.. l(rr r2Pyne, S.G.,Dong,Z.JOC 61,5517(19%). "Bienayme,H. BSCF132,696(1995). r4lautens, M., Ren,Y. JACS118,10668( 1996r. 35Saulnier, D.B., Deshpande. \l S M.G., Frennesson, 36suito,S., Salter,M.M., Gevorgyan,V., Tsubola. (l996).

(Ph3P)aPd/ PhMe A

zHrs

brH,u

^J,

ETOOC

(Ph3P)aPd/ PhMe

CzHrs

O

2,2,3,3-T etramethoxybutane and 9,9,10.11)-& Protection of 1,2-diols.t'2 These reagcr HC(OMe), in methanol containing a linle sul derivauvt reaction,2,3-dimethoxy-1,4-dioxane Diequatorial diols are selectively protectd- . directly by the reaction of a l,2-diol u'ith i

- KzCO3 (PhsP)+Pd MeCN, 50o

52"k

methanol in the presenceof camphorsulfonic e

Conjugate enynes dimerize to give aromatic products.r6 rGarro-Helion, F., Merzouk, A., Guibe, F. "/OC58,6109 (1993). 2Kraus, G.A., Watson, B.M. TL 37, 528'l (1996). 3cummins, C.H. TL35,857 (lgg4). -Xiang, J.S.,Mahadevan,A., Fuchs,P.L. "/ACS118,4284 (1996). 5Hitchcock, S.A., Mayhugh, D.R., Gregory,c.S. ZL 36, 9085 (1995). oAnderson, J.C., Namli, H. SL 765 (1995). 1 W ang,X.-Z.,Deng, M.-2. JCS(P I ) 2663 (lgg6i). nHildebrand, J.P.,Marsden,S.P. SZ 893 (1996). eBuszek. K.R., Jeong,Y. TL36,56'/1 (lgg5). f 0Rossi, R., Belf ina, F., Carpita, A., Mazzarella, F. T 52, 4Og5(1996). ' 'Sakamoto, T., Kondo, Y., Takazawa, N., Yamanaka, H. JCS(P I ) 1927 (1996). ''Zhu, L.-S., Huang,Z.-Z'Huang, X. f 52,g81g (1996). ''Hutzinger, M.W., Oehlschlager,A.C. IOC 60,4595 (1995). loKubb*u, J., Hoffmann, C., Schinzer,D. S 299 (1995). r5vi"u.t, N., Cazes,B., Gore, J. T 52,9101 (1996). t6ciufolini, M.A., Mitchell, J.W., Roschangar,F.TL37,8281 (1996). "Sakamoto, M., Shimizu,L, Yamamoto,A. Ca 1101(1995). l8Khan, F.A., Czerwonka,R., Reissig,H.-U. S4 533 (1996). leNegishi, E.1., Ma, S., Amanfu, J., Coperet,C., Miller, J.A., Tour, J.M. "/ACS118, 5919 (1996). 20luo, F.-T., Wang, M.-W., Liu, Y.-S. H 43,2125 (1996). "'Yasui, K., Fugami, K., Tanaka,S., Tamaru,Y. JOC 60, 1365(1995). "Walkup, R.D., Guan, L., Kim, Y.S., Kim, S.W. ZL 36, 3805 (1995). "Satoh, T., Tsuda, T., Kushino, Y., Miura, M., Nomura, M. JOC 61,64'76 (1996').

HOr,,fOOMe

xo"'\.\on : 0n

MeO

O

ueo)HC(OMeh J

/-oH ,,. H

rMontchamp,

O

O

HC(OMeb. C{

J.-L., Tian, F., Hart, M.8., Frost, J.\t

2,2JJ-Tetramethoxybutaneand 9,9,10,10-tetranethoxy.9,10-dihydrophenanthrene

raMarshall, J.A.,Wolf, M.A. JOC 61.3238O996\. :5Marshall, J.A.,Wallace,E.M..Coan.p.S./oC;0. :/96(tggs). :6Doi,T., Yanagisawa, A., Nakanishi,S.,Yamamoto,K., Takahashi, T. JOC 61,2602(1996). -' Thorimbert, S.,Malacria,M. TL 37,8483( 1996). :8vi.un. N.,Cazes, B.,Gore,J.TL36,535( 1995). resuku-oto, M., Shimizu,I., Yamamoto,A. BCSJ69,10650996). Y., Tanaka, A., Yasui,K., Goto,S.,Tanaka,S.ACIEE34,787(lgg5). l5**, "Tamaru, Y., Goto,S.,Tanaka, A., Shimizu,M., Kimura,M. ACIEE3S,87S(1996). s.C.,Dong,Z.JOC 61,5517(1996). llPyne, '"Bienayme, H. BSCF132,696(1995). r4lautens, M., Ren,Y. JACS118,10668(1996). 35saulnier, M.G.,Frennesson, D.B..Deshpande, M.S..Vyas,D.M. TL36,7841(lgg5). 'osaito, S., Salter,M.M., Gevorgyan,V., Tsuboya,N., Tando,K., yamamoto,y. JACS118, 3970 (r996).

I

(2C03

r'

2,2,3,3-Tetramethoxybutane and 9,9,10,10-tetramethoxy-9,10-dihydrophenanthrene Protection of 1,2-diols.l'2 These reagents are prepared from the diketones and HC(oMe), in methanol containing a little sulfuric acid. By an acid-catalyzed exchange reaction,2,3-dimethoxy-1,4-dioxane derivativesare formed in the reactionwith 1,2-diots. Diequatorial diols are selectively protected. Actually, the protection can be performed directly by the reaction of a l,2-diol with an s-diketone, trimethyl orthoformate. in methanol in the presenceof camphorsulfonic acid.2

HO,,.COOMe c|, (

, . ,

-r

\N-

Ph

SPh

Hooc...,l..-//..7,2 Tick / cH2ct2

I (

0-r'-..2 .

/

-t7 )""

/)-o o'

t

Michael and aldol reactians' The \ts Eitherthenn- c is diastereoselective.T acetals

)""\--j

I

-7oo, 5 min

56/"

8

23o , 1 min

50"/"

I

o Intramolecular electrophilic reaction of imines using a 2-propylidene-1,3-bis(silane) unit as nucleophile can lead to bridged heterocyclic frameworks.3

I

OTBS

TiO{

MecHAggur

cH& -7gc

trqn (+sa/ r tro.n (asjr/

ETOOC 7rtvtqsi-1 | Me3siJ

r

TiCl4;

As an alternative method to the foregorng chains, the aldol reaction8 is useful. An anr estersin which substituentsat the 2.3-postoc

KHC03

\

MqSi 80%

cycloadditions involving allylsilanes. Ticl4 promotes [2+2]-cycloaddition of allylsilanes to o-keto esters,leading to oxetanes.aA [4+2]-cycloaddition processthat gives 4-silylmethyl-l,2,3,4-tetrahydroquinolines is in contrast ro the formation of N(3-butenyl)anilinesusing allylstannanesinsteadofallylsilanes.5 (Note that the cycloaddition need not be restricted to allylsilanes and that N-(benzenesulfenylmethyl)anilinesundergo the same cycloaddition with alkenesin the presenceof TiClo-pph..)6

TBS9

. l l \-/'V

I

oPMB

oBCx2

\

'_ o H c: . \ / \

l

l

:

a-Phenylseleno h Carbocyclization. bl sclcoo I accompanied undergo cyclization Ph\...cooEt

Y o

Ph

\

Ph. /cooEt

+

,t'T-

Ph

Tict4 P h M e ,0 o

o..)

( fn,. ,t'-fP

960/"

h

l

O{i

{

Titanium(IV)chloride

Z':(^\ ll I

TiCl4/ CH2C|2

PnN^ttPh

,

(*)

y'tu*'

\tttt

:

,

,,ul-Y

Z-:aN\ ( / ) il

-siMe3 MRe = SnBus

MR3= SiMe3

sPh

z

or

I

.7go

Ph SPh

H

H

tbr lactone opening or displacement

I ( )""'\z

)-o o'

343

reaction of ketene silyl Michqel and aldol reactions. The Mukaiyama-Michael Either the syn- or the anfi-isomers are obtained at will' acetalsis diastereoselective.?

)""\-/ 8 'I

O i

-j-V\ ri.:-'. u.ing a 2-propylidene-1,3-bis(silane) , 1 ;\ - - :r.rmeworKs.'

I

l

*

l

M"cHAsBut

CH2Cl2

+\coSBur

from (a-silyl acetal

er' promotes [2+2]-cycloaddition of T t - r 1+21-cycloaddition processthat gives a.. ' .()ntrast to the formation of Nd : .,r.r l.i lanes.s(Note thatthe cycloaddition ^L:r1c'nesulfenylmethyl)anilines undergo 5{"

+/.tcosBu'

-7go from (E)-silyl acetal

I

.

OTBS

99%

5

95

83ok

91

9

for the assemblyof polypropionate As an alternative method to the foregoing allylation of imines provides p-amino reaction chains, the aldol reaction8 is useful. An analogous estersin which substituentsat the 2,3-positions ue anti'e

Tic14

cH2cl2 85% (> 99% de)

:,:,,t TiCl,-PPhr.)b Carbocyclimtion.c-Phenylselenoketonesbearinganunsaturatedsidechain undergo cyclization accompaniedby seleno group transfer'r0

TiCh t

CH2Cl2 -4oo 78"/o Gxo: endo 91 :9)

344

Titanium(IV)chloride-triethylamine

Anilinomethyl azi.des.rl N-(Methoxymethyl)anilines readily undergo functional group exchange.with riclo and Me,SiN, in cHrcl, at -78" the methoxy group is replaced by azide.

The direcrrcn Dieckmanncyclization.z promoted by TiClu-EtrN is dependent tr 5-thia-2-oxocyclopentanecarboxylicesten arrl

Nitrogenation.t2 A remarkable reaction that uses N, to incorporate nitrogen into organic molecules is achieved by the catalytic system composed of riclo (1.25 equiv), Li (12.5equiv),and MerSiCl (12.5equiv).

are formed selectively.

o

,'>-4 i l t p i(

o

T i C l a - L i- M q S i C l THF, N2

o

L, 24h

a'A I I I N -

H

1_cooEt \y^cooR

TiCl4 - Et3N

C H 2 C | ,2 - l d

X . !

o

Simmons-Smith reaction. The formation of RCH:CHCHTOZnCHTI is not necessarily followed by cyclopropanation. However, the addition of catalytic amounts of TiCl. has a dramatic effect.r3 other Lewis acids, such as Et2Alcl, BBr., and Siclr, are effective as well. Asymmetric induction is realized by using TADDoLate*Ti(opri.y,. ' Jain,N.F.,Takenaka, N., Panek,J.S..IACSll8, 12475(1996). 'van Oeveren,A., Feringa,B.L. JOC 61,2920(1996). 'Kercher, T., Livinghouse, T. JACSf18, 4200(1996). Akiyama,T., Kirino,M. CL723(1995\. 5 Hu, H.-J.,Ahn,y.-G.,Chon,J.-K.JCS(PI ) 2631(gg5). n Beifuss, U., Ledderhose, S. CC 2137,|ggr. Totera, J.,Fujita,Y., Fukuzumi, S. f 52,9409(1996). oEvans, D.A.,Dart,M.J.,Duffy,J.L.,Rieger,D.L. JACS117,9073 (1995). 'Shimizu, M., Kume,K., Fulisawa, T. CL 545(1996). loToru, T., Kawai,S.,Ueno,Y. SL539(1996). "Ha, H.-J.,Ahn,Y.-G.SC25,969(t995). ''Mori, M., Kawaguchi, M., Hori,M., Hamaoka, S.-i.1139,729(1994);Hori,M., Mori,M. JOC 60, 1480fi995). t3ch-"tt", A.B.,Brochu,C. JACStll,11367 lgg5\.

'Curdillo, G., Casolari, S., Gentilucci, L., Tomasrru.( 2Deshmukh, M.N., Gangakhedkar,K.K., Kumar. L'S

Titanium(IY)chloride-zinc.13,310-31l : lt Reductionof sulfuxides.' The applicah aryl sulfoxidesextendsthe useof the lanercor followed by the reduction and Lrrr tr includingsp cyclopentanones, 2,2-disubstituted

IiCl4 - Zn

THF

^ a"9 tnd

t

5-100,3h

CZ..

Amides."

The reduction of nitro compol

to amides directly. Titanium(IV)

chloride-triethylamine. Chiral aziridine'2-carboxylates.t The generation of enolates and their subsequent cyclization occur when B-benzyloxyamino carbonyl compounds are treated with TiCl4-EqN. Since the chiral substratesare readily available,this reaction realizesa valuable synthesisof chiral aziridines.

"rr ^

O

NHOBn

Jl I \

\,' -N.Ar.tI Y""pn

Tict4 Et3N - CH2Cl2

jar,'ix

-*9',n

'Fitjer,L., Schlotmann, W., Noltemeyer, M. fL 36.{ 'Shi,D.-Q.,ZhoU.L.-H., Dai,G.-Y.,Chen,w.-X. 17

Titanium(IY) chloride tris(triflate). The catalyst TiCl(OTf Esterification.' equimolar amounts of carboxylic acds

octamethylcyclotetrasiloxane. Friedet-Craf* acylation.? The catalls effective promoter of arene acylation with anh 6l-98Vo).

Titanium(IV)chloridetris(triflate)345

nl

u

rr' -.

readily undergo functional the methoxy group is replaced

u \ . \ to incorporatenitrogen into n - :rposed of TiClo (1.25 equiv), Li

Dieckmann cyclization.2 The direction of cyclization of 3-heteroadipic esters promoted by TiClo-EtrN is dependent on the heteroatom. Thus, the isomeric 5-thia-2-oxocyclopentanecarboxylicesters and 4-aza-2-oxocyclopentanecarboxylicesters are formed selectively.

EIOOC,

.O

-'\__r(

//o

|

;coort \x'^cooR

Tict4 - Et3N C H 2 C | 2 ,- 1 0 o

o'

(r\.oor"

,9

tUi

.NH

-( x

R('H:CHCHTOZnCHTI is not ::: .rJtjitionof catalytic amountsof r: .,. Et.AlCl, BBr., and SiClo, are -. ' : TADDOLate-Ti(OPri)2.

X = N R ,R = E t

X = S ,R = M e

o

rC.dillo, G.,Casolari, L., Tomasini, C. ACIEE35,l848(1996). S.,Gentilucci, rDeshmukh, K.K., Kumar,U.S. SC 26, 1657(1996). M.N., Gangakhedkar,

TitaniumflY) chloride-zinc.13,310-31I ; 18,364 Reductionofsulfuxides.t The applicabilityof this systemin reducingcyclobutyl with ketones Thus,condensation aryl sulfoxidesextendsthe useof the lattercompounds. followed by the reduction and Lewis acid-catalyzedrearrangementleads to includingspiroketones. cyclopentanones, 2,2-disubstituted

i , 1995).

IiCh- Zn THF 5 1 0 o , 3h

eg-l): Hori, M., Mori, M. JOC ffi.

;Tol S- -

/u

: :

.z

OBz

I i . \,/, \,2

: OR\

Titanocene dicarbonyl. Intramolecular Pauson -Khand reoctbt' catalyzescyclopentenoneformation in a mo&r of a dienone from an allenyl alkyne is intereqtr

tl

tl

Cpzfi(Prrq

F{

co 9d

Titanocenedictrbonyl 347 The Sharplessasymmetric epoxidation reagentcan be Baeyer_viltiger oxidation.z usedfor the conversion of cyclobutanonesto chiral Tlactones'

o\ide. r :': preparation of these compounds The catalystisderived |.:." . .i'rtr'carbonate'

r'"',

*t-

\.,.\

OTIPS

47"k

r : :- r'..rnepoxide or oxetanering is attached rn:'::.ltion. Both rings undergo cleavage' E t ::lr.

Phs.,sPh

(rr.Pro)aTi I-BUOOH- (+)-DIPT -200. 6 h

o-o)."to" 34o/o ee

rMahrwald. B' S 1087(1996). R.,Costisella, 2lopp,M., Paju,A., Kanger,T.' Pehk,T' TL37"1583(1996)'

,,j

I r-l

Ho- Ho

-'

,^OH

Titanium(IV)iodide-lithiumaluminumhydride-fluorotrich|oromethane. acetic acids by the Homologationof ketones.r A synthesis of 0,cr-disubstituted low-valent titanium a using chain extensionof ketonesinvolves condensationwith cFCl3 reagent. rGarcia, J'V JCS(Pl)l77l (1995)' M., delCampo,C.,Llama,E.F.,Sinistena,

Titanocene borohYdride. in DME' The Reiluction.r The reagent is prepared from CprTiClt and NaBHo not changed,even profile is reduction the reagentprepared in situ works equally well, and borohydride' of titanocene reactivity as borane is cogenerated,owing to the superior

I

)r\,rSnau' I OBn

2'

Tributylphosphine-N,N,N iN'-tetramethylazodicarboxamide' This reagent system is useful for activating hindered Mitsunobu reaction.t 4-Methoxybenzoic acid is the nucleophile of choice. for inversion. secondaryalcohols

I Arterbum,J.B.,Perry,M.C. TL 37,"7941(1996). 2Art".bu-. J.B.,Nelson,S.L.JOC 6l'2260 (1996).

Trichloroethylene. A synthesis from alkyl- or arylthiols is accomplished through Alkynyl sulfides.t complete dechlorination to generate the trichloroethylene, with s-alkylation C-alkylation. and species, thioethynyllithium

-,SnBu3

I

or

KH / CICH=CC|2

.,^.,1,,\//\sH

ar.sn{Ph OH

BuLi: Mel/HMPA

tN"boir.P.,Kann,N., Greene, A.E.JOC 60,7690(1995).

^^^,,,\

",/

360

TriethYlsilane

"'"1|ff;H"*tto,Iir*'andimines'l.."-1'::T^::,.t*tlJ:,?H:t"*" in andamines'respectively' andiminesto atcot'ots tonn"n"ig;i;tn'ut' system, reducing them into allyldichloromethane' actilaled by converting' are bromides synthesis of Atlylation. Allylic utOtttyOt''; A convenient *nn "cl"Ut"* trichlorosilanes,which. is basedon this process' cr-metttytene-1-lactones

COOMe

)...,''

RcHo

CoOMe ,ul .sicts

cl3siH CuCl- ,Pr2NEt Et2o A

, M6cN- DMF

// \/

oyuto,M., Homma,K', Ishida,A' t/ 4l' l- ' l9 r'x til;,;.;.. P;"c. S.-Y. Magrath'J s lJq \l tt Hilbom' ' H w Mites' H.R]. d;;;". rl ti"t"art*".i*' R'' Matteson'D S' Olt lt' F er:. Grcr D' ';il";il;;'w'' chmielewski'

lt' -1'6- i-' Trifluoroacetic anhydride' un Quinones'r P-SulfinYlPhenol: I product' the of (CF3CO)rO. Hydrolysis

oH tooMe _^. H

ffi-84%

:::1,\3#" lfilil:'.,l1 3:I"ilil$,*l,TiJl,l

Thc r TrifluoromethYlketones': RCOCF.' gives o' anlb Vinylogoustrifluoromethyl inducol N-oxides tertiary amine Thismethodr' m trifluoroacetylation'r

*"';:;#;!,ii,#!;.fi *tr*td*'"up:.;a:fi:l;':1T;T: ule [yurv"-I"aryl and enol triflates'to ^. conttgur of "^"n""ration.3 proceedswith retention ;#;;a;g

r-\ )L*Ao "q. Ph

-r

Et3SiH - TiCl4 t

/-,.rAo I

(-rn OH

rd5l"

59% (80% de)

Aromatic ketones

Et"SiH-TiCl4' by reaction are deoxygenateda 'with

Reituctionorniroc,nll:,:;:;;;;;:t".:l':i:'""*#"'Ji:'*Jil::tl; but the reductt

etrsiH-cnrcooH's **;rin"'.;; is usedfor .l"ttr.a uyirnrit',Rnct'o '"'""iiirli;;otioiond re of Et,SiHandBCl, o' give hvdrosilvtation 'T:1*;"r",'.i' i""iugatei dienes alkvldichlottri"Jr}il#;ili"i'it'" to leading pt"'"n"" or in the p hvdroborationof alkenes' *itt' EttSiHphotochemically /Z)-alkenyltriethyt'ltun""t'ofilut?io" Cr(CO)u. r B o u k h e r r o u bR' ' C h a t g i l i a l o g l u ' C'

(1996)' Man-uel'G Oi4 l5'1508

i];" *'*t I i'1"1-'l!f i?:l#i ii.: :T;"iiliii'td sFreville.S., Celener,l.r.' r

lAkui, S.. Tuk"da, Y.. lio. K ' Yoshrda \'

';;;i", i . ElKaim' L"z*d's z rsr sI wenrland ,il;;;,;. Chauncy.8.. K \t J /l '*"-n0.,O.t..Liu'K" Brands'

T rifl uoroacetonitrile' tinc 4-T riflu oromethYl imidazo 4-trifluoromethyl-A3-imidazolin

Trifluoroac€tonitril€ 'Yato,

: HSiCl, and DMF forms a :,,1: and amines,respectively,in

L-

.()n\erting them into allyl.-\ convenient synthesis of

M., Homma, K., Ishida, A. H 41, tj (lgg5). Wu, P.-L., Peng, S.-Y., Magrath, I. S 249 (1996). Trinkman, H.R., Miles, W.H., Hilbom, M.D., Smirh,M.C. SC26,g'73 (tggfir. Soundararajan,R., Matteson, D.S. OM 14,4l5j 0995\. 'Abdelqader, w., chmielewski. D., Grevels, F.-w., ozkar, S., peynircioglu, N.B. oM 15, 604 (1996').

Trifluoroaceticanhydride. 18,376-377 Quinones.' p-Sulfinylphenolsundergopummererrearrangement on reactionwith (CF3CO)2O. Hydrolysisof theproductsaffordsquinones. OH COOtil€ ,.,,_\.oMF

R/v\ 63 - 84%

(cF3co)2o/ cH2ct2 aq. NaHCO3 - MeOH

84V"

E : ::ll reducesorganic halidesl and :., . .rgeof the C-O bond of a fused !:

Trifluoromethyl ketones.2 The reaction of acid chlorides with (CF.CO)"O-pyridine gives RCOCF,. vinylngous trifluoromethylamides. The potier-polonovski rearrangement of tertiary amine N-oxides induced by (cF3co)2o is frequently followed by trifluoroacetylation.3This method is most suitable for the synthesisof (-)-altemicidin.a

,l_\ I r

t OH

on "

59% (80% de)

il HN. Y

,,/

- py (CF3CO)2O cH2ct2

cFg r::: F-t.SiH-TiClo. t\.::.r,/ones are reduced to tosylr(:t ,)l- nitroarenesto arylamines is rr ,l EtrSiH and BCl, is used for or,:.rnes.7 Conjugated dienes give F:,,r()chemicallyin the presenceof

i. te96). E.qe5). l ^ : 1 r1 9 9 5 ) .

o 65%

rAkai, S., Takeda,y., Iio, K., yoshida, y., Kita, y. CC 1013 (1995) 'Boivin, J., El Kaim, L., zud, s.z. T sl, 2573 (lgg5\. twenkert, E., Chauncy, B., Wentland, S.H. SC 3, j3 (1973). -Kende, A.S., Liu, K., Brands,K.M.J. ,/ACS lt7, 10597(1995\.

Trifl uoroacetonitrile. 4-Trifluoromethylimidazolines.r CF3CN is a l,3-dipolarophile that forms 4-trifluoromethyl-A3-imidazolines with azomethineylides. Derived from simultaneous

Trilluoromethanesulfonicacid(triflicacid)

362

Trlh

N-acylation with Fmoc-protectedamino acid fluorides, the adductsare amenableto peptide synthesis. The heterocycle is readily cleaved to generate 3,3,3-trifluoro-2-ketopropyl amides, the members of which are potent inhibitors of esterasesand proteases.

Lactonization.* Lactone formauoo which the other propargylic posirion rs sr achieved by treatment with triflic rrd rC complexes are demetallated on further trcatn

o

o Fmoc-NH. A :

:

F

? ? n

Ph

+

? -

Fmoc-NH. ,)\* ) : N

(.,"".

Pht

Ph''

cF3cN

tl Ph Fmoc-NH. ,'1. Y N{ : l r N Ph'

x cFr

-l

rDerstine,C.W.,Smith,D.N., Katzenellenbogen, J.A. JACS118,8485(1996)'

2-(Trifl uoroacetylsulfenyl)pyridine-1'hydroxybenzotriazole. Peptide synthesis.t The combined reagent is useful for acylating amino esterswith N-protected amino acids with minimal racemization. rS"h-idt, U., Griesser,H. CC 146l (1993).

(3,4,5-Trifl uorobenzene)boronic acid. A carboxylic acid and an amine in refluxing toluene form the amide in the Amides.l presence of this extremely active amidation catalyst (14 examples, 87-99Vo). Slightly higher temperaturesare required for hindered acids, such as l-adamantanecarboxylic acid, and for lactamization.Proline gives the tricyclic diketopiperazine(94Voyield) in hot anisole.

9,10-Diarylphenanthrenes.5 Tetraanl threne derivatives on exposure to mfl 1,2-di(3-pyridyl)ethanediol, which underScs

At,

At

TrO{

HoxoH

tlrhiha.a,K., ohara,S.,Yamamoto,H. JoC 61,4196(1996).

Ph

Ph

Ar:9

Trifluoromethanesulfonic acid (triflic acid). 14, 323-324; 15' 339; l8' 377 A simple preparation is to store a mixture of an arene, sodium Diaryl sulfuxides.r arenesulfonate,and triflic acid at room temperature. An improved condensationof an aldehyde with two N,N,-Alkylidene bisamides.' molecules of an amide is promoted by triflic acid. Nascent carbocations generated from alcohols (using TfOH or Schmidt reaction. SnClo)are trappedby the addedalkyl azides.l

(-\

l'v X

TfOH:

,/

+

OH

R

N

3

NaBHa 95%(R = rrBu)

^Yamamoto, K., Miyatake, K., Nishimura. 't'.. Tgs tFemutdez, A.H., Alvarez, R.M., Abaio, T.Il S ll rP.-son. W.H.. Fang,W .-K. JOC ffi. 496Or 1995, -Chen, C.-C., Fan, J.-S.,Lee, G.-H., Pens. S.-\l . $ toluh. c.e.. Klumpp, D.A.. Neyer, c.. iang. e s

Trifluoromethanesulfonicanhydride (triftr 15,339-340; 16,357-358;18,3'77-378 Cyclodehydration.t Hydroxyalglenol Tf,O. A remarkablesolventeffecthasbeendi

363

Trifluoromethanesulfonicanhydride(triflicanhydride)

LactoniZation.a Lactone formation from propargylic alcohols and homologs in which the other propargylic position is substituted with a tungsten residue is readily -40', The n-allyl achieved by treatment with triflic acid (0.25 equiv) in cH2cl2 at complexes are demetallatedon further treatment with CFTCOOH.

, ::.r .rJrluctsare amenableto peptide 3131.,11'-1.3,3-trifluoro-2-ketopropyl a.l.:r\es andproteases.

o ll

Fmoc-NH:-\*4

Ph

cF3CN :

Ph..

|

,N

Y 70"/"

cfr

Ho:.-..,

cpw(co)sNa

,,'^\._,",,t._, ;;,ot,.to

"oY^) .^\

\t-,.,.'\-,

cF3so3HY"'?l

"","i -4oo

6-r-,1J n

CpW(CO)z

84%

cF3cooH cucr. J

I tF .rs5 ( 1996).

o>-o-1.---. t t \-,zt'-.'-

uotriazole. l\': .-i lirr acylating amino esterswith

H

457"

e:- .., :nS toluene form the amide in the -r examples,87-99Vo). Slightly '.: acid' i.-- - .r' I -adamantanecarboxylic 1.; :1: r.tzine(94Voyield) inhot anisole'

9,10-Diarylphenanthrenes.5 Tetraaryl-1,2-ethanediols are converted to phenanthrene derivatives on exposure to triflic acid. An exception is l'2-diphenyl1,2-di(3-pyridyl)ethanediol, which undergoesnormal pinacol rearrangement'

o'\--l Ar

Ar

HoxoH Ph

Ph

d;rb Ar = Ph,4-ClCoH+ ,

l:

tr . :. a mixture of an arene, sodium r,:..:r;r..ttion of an aldehydewith two E:.::iJ from alcohols (using TfOH or

a'Y lr

> 98o/o

: l - 1 . 1 5 , 3 3 9 ;1 8 , 3 7 7

\-.NR 95'o (R = n-Bu)

rYa-umoto, K., Miyatake, K., Nishimura, Y., Tsuchida, E. CC 2099 (1996)' 2Femandez,A.H., Alvarez, R.M., Abajo, T.M. S 1299(1996). rP"-ron, W.H., Fang,w.-K. JOC ffi,4960 (1995). aChen, (1995)' C.-C., Fan, J.-S.,Lee, G.-H', Peng,S.-M.' Wang, S.-L., Liu, R'-S' JACS ll7'2933 soluh, G.e., Klumpp, D.A., Neyer, G., Wang' Q. s 321 (1996).

Trifluoromethanesulfonicanhydride (triflic anhydride).13, 324-325;14,324-326; 15, 339-340; 16,35'l-358; 18,377-37 8 Cyclodehydration.r Hydroxyalkylenolethersundergocyclizationon treatmentwith Tf2O.A remarkablesolventeffecthasbeendiscovered'

l

364

p-(TrifluoromethareInL

Trifluommethanesulfonicanhydride(triflicanhydride)

aY") \-,.'a

Activation of N,N-dimethylacrybnidc. bifunctional electrophile for elechon-rich arcrr 1-indanones.6

rt20 250

OH

in CH2C|2

13

in PhMe

97

87 J

Certain homoallylic alcohols cyclize in the presence of Cyclopropanation,' TfrO-collidine. The introduction of various functionalities at the o,-position of the cyclopropane ring is possible by treating the cyclization mixture with nucleophiles (C- and X-). On the other hand, triethylamine effects a clean elimination to give high yields of

.. ,NMe2

]f

+ TJ2o

,a...-rNMe2 + l oTf Tto-

alkenylcyclopropanes.

Nitration and nitratation,T Nitronrum I and TfrO. Adamantanegives I -nitro- or I -nrtra

Tf2O- collidineI CftCl1

enO\r,

'

87"/"

BnO

nitromethaneor dichloromethane,respectrrelr

lot

Tf2O - collidine / Cl-!C12, -78o ;

Et3N

Combined with DMAP, triflic anhydride is Bischler-Napieralski cyclization.' effective in inducing the cyclization of N-biphenylyl carbamates.The method is applicable to the total synthesisof several amaryllidaceaealkaloids.

Tf2o - DMAP cH2cl2 , 0o-> d

Trifluoromethanesulfonyl azide (triflic ezil Organoazidesfrom prilrury amines. l Free hydroxyl groups do not disturb this reatx rAlper,P.B.,Hung,S.-C.,Wong,C.-H. TL 37.At]s

\ z O

N-COOMe

ll.hih*a, K., Hanaki, Yamamoto, N., H. CC I I t- | 2Nugusu*u, T., Handa,Y., Onoguchi, Y.. Suzutr.K rBanwell,M.G.,Bissett, B.D.,Busato, S..Coudcn.C Wu, A.W. CC 2551(1995). 4Hendrickson, J.B.,Sommer, T.J.,Singer,M. S l.l% sNirhiyu.a,T., Seshita, T., Shodai, H., Aoki.K.. Kr 6Nenajdenko, V.G., Baraznenok, LL., Balenkora-L.t 'Duddu, R., Damavarapu, R. SC26, 3495( I 996r

,r*1 /-\

\r /-\

/-\ -\o,

rg

Phosphinimines.a A simple preparation of R,P:NH from a phosphine oxide involves the evaporation of a mixture of it with TfrO and NH.. The process is repeated several times. Access to these unsubstitutedimines by the Staudinger reaction is difficult. becausethe imines are hygroscopic and hydrolyzableCouplings.s Grignard reagents RMgX of various kinds, including alkyl-, aryl-. vinyl-, and allylmagnesium halides undergo homocoupling induced by TfrO in refluxing ether for a short period to give R-R (10 examples,48-95Vo).

p-(Trifl uoromethanesulfonyloxy)vin1'lindod DiaryliodoniumtriJlates.' An efficrea aryllithiums leads to (ArIAr')+OTf-.

Phl(OAc)2. 2TfOH

\ _ ,

cH2ct2

lKitu-u.u,

T., Kotani, M., Fujiwara, Y. fL 37. -r-: I

p-(Trifluoromethanesulfonyloxy)vinyliodonium trifluoromethanesulfonates

Activation of N,N-dimethylacrylamide. The O-triflyl salt of the amide is a bifunctional electrophile for electron-rich:uenes.Thus, the salt is useful for the synthesisof 1-indanones.o

I

87

I J

97

v"o$or'4" a-,::,'l: cyclize in the presenceof n.:: 'n.rlities at the q-position of the er: :. nrrrturewith nucleophiles(C- and

+

,, 1 , N. M I E2

Tf2O

orf Tfo-

Ir,,- :lrmrnation to give high yields of

eno!.

c H 2 c t 2A ; K2CO3 / HzO

63"k Nitration and nitratation.T Nitronium triflate is generated in situ from BuoNNO, and TfrO. Adamantanegives 1-nitro- or I -nitratoadamantaneon exposureto this reagentin

" I o/

'Ithih-u, K., Hanaki,N., Yamamoto,H. CC I I 1'7(1995). zNugu.u*u, Y., Suzuki,K. BCSJ69,3l ( 1996). T., Handa,Y., Onoguchi, 3Banwell, D.C.R.,Holman,J.W.,Read,R.W., C.J.,Hockless, M.G.,Bissett, B.D.,Busato, S.,Cowden,

87"/.

Bno\^.\,,, 90v.

nitromethaneor dichloromethane,respectively. Thus, there is a marked solvent effect.

tl

Dc,j .\ rrh DMAP, triflic anhydride is The methodis applicable \ -.:r-hamates. a- .:.

.Wu, A.W. CC 2551(1995). *Hendrickson, T.J.,Singer,M. S 1496(1995). J.B.,Sommer, 5Nirhiyurnu, H., Komura,K. CL 549(1996). T., Seshita,T., Shodai,H., Aoki, K., Kameyama, oNenajdenko, LL., Balenkova, E.S. I52, 12993(1996). V.G., Baraznenok, 'Duddu,R.,Damavarapu, R. SC26,3495(1996).

azide (triflic azide). The diazo transfer is catalyzed by CuSOo. Organoazidesfromprimaryamines.' Free hydroxyl groups do not disturb this reaction. Trifluoromethanesulfonyl

rAlper,P.B.,Hung,S.-C.,Wong,C.-H.rL37,6029 (1996).

) p-(Trifluoromethanesulfonyloxy)vinyliodonium An Diaryliodonium tritlates.' aryllithiums leads to (ArIAr')+OTf-.

c: R P:NH from a phosphine oxide T: , t .rnd NHr. The processis repeated l.. ^. rhc Staudingerreactionis difficult. tbr

\i:r,,Lr\ kinds,includingalkyl-, aryl-, n .-rhnginducedby TfrO in refluxing " .:. .r5(i-).

efficient

trifluoromethanesulfonates. ligand exchange of the salts with

Phl(OAc)2. 2TfOH

-l lKitu-uru,

CH2Cl2

ArLi/ THF ....-.-"._

+ Ar-l-Ph

TfO

- 7 5 0, 2 h

67 - 93"/.

T., Kotani, M., Fujiwara, Y TL37.372r (1996).

366

(Trifluoromethyl)trimethylsilane

S-(Trifluoromethyl)dibenzothiophenium salts. 18, 378 Trifluoromethylation. Reaction with enolate anions requires the presence of B-phenylcatecholborane.I

5Movchum, V.N., Kolomeitsev,A.A.. yazumlshr. 6Prakash, G.K.S.,Yudin,e.f., oemeux.b- Oul-

Related trifluoromethylating agents are analoguesbased on different chalcogen atoms (S, Se, Te).2 The zwitterionic sulfonates 1 are also known.3

Trifl uoromethylzinc bromide. Difluoromethylethers.t Prima4 arxl difluoromethyl ethers on reaction wirh CF.Zrr

'Miethch"n, R., Hein,M., Naumann,D.. Tr.rra-\t r Triisobutylaluminum.

2-Hydroxytetrahydrofurans.t Tnrsr:,hr catalyze the isomerization of 4-methl.lenc- l. C-O bond cleavageand C-C bond formaucn r of the intermediate.The 4-methylene-l.-1"Jro lUmemoto, Adachi,K. T., JOC 59,5692(lgg4). 2u."rnoto,T., Ishihara, S. JACS115,2156(1993). 3Umemoto, T., Ishihara, S.,Adachi,K. 1FC74,77(1995). I

(Trifluoromethyl)trimethylsilane.

L5, 341; 18, 378-37 9 A new preparative method involves the reaction of Me.SiCl with Preparation.' CF.,Br and aluminum in NMP at room temperature.The yield is 627o. anions are generated when Nascent rifluoromethyl Trifluoromethylation, 'of fluoride ion. Nucleophilic trifluoromethylation is in contact with a CF.,SiMe. oxazolidinones is for the synthesisof protected q,-amino trifluoromethyl ketones.2

Prr'-\r{ t t\l BnOCOO-''-

// /

o

cFt -osiM""

Me3Si-CFg

tn-Yo

CsF / THF )))

anocoo-NJ

N^'

l \-/

l

FO u

Cp2TiMe2 THF, 650

t

6fi

Thiazolines from esters,' 2-Mercapcr combine, with the concomitant eliminarion of r in toluene.

Sigmalropicrearrangements. The CLu promoted by l-BurAl. Furthermore, the cartx reductionto fumish 4-alkenols.3A stannrl grc silylstannyl-substitutedallyl vinyl erhers Bh presenceof i-Bu,A1.a

95o/"

The formation of trifluoromethyl sulfides (and other chalcogenides)from thiocyanatess or disulfides,a CF.,SiMe.,,and Bu.,NF is possible. The combination of sulfenyl chlorides.

a"ta'"Xot"

CF.,SiMe,, and TASF is also effective.s (Trifluoromethyl)tributylstannane is readily prepared by the reaction of bis(tributyltin) oxide with CF,SiMe-,.usingBuoNFas an initiator.6 rGrobe, J.,Hegge,J. SL64l (lgg5). 'Walter, (1995). M.W.,Adlington,R.M.,Baldwin,J.E.,Chuhan, J.,Schofield, C.J.TL36,17761 'Billard, T., Large,S.,Langlois,B.R. ?t 38, 65 (199'1). 'Billard,T., Langlois,B.R. TL37,6865(1996).

iBu3Al cH2ct2 , oo

--MMe3

'98% ee)

OLr

o 'Flemming, S.,Kabbara,J., Nickisch,K., Westermann, J.,Mohr,J. SZ lg3 0995). 'Pimrng, M.C.,Chau,J.H.-L.JOCffi,8084 (1995). -Diederich, M., Nubbemeyer,U. ACIEE 34, 1026(1995). -Nubbemeyer, U. JOC 60,3773(1995). 'Nagasawa, T., Taya,K., Kiramura, M., Suzuki,K. "/ACSll8, 8949(l996).

Trimethylhydrazinium

(1)

'Takeda,

iodide.

Ar-aminations.I Nit.ou."nes undergo amination by vicarious substitutionwith (MerNNFl)*I- in DMSO upon addition of r-BuOK. 'Pagoria, .|99fir. P.F.,Mitchell,A.R.,Schmidt, R.D../OC61. Zg34

)--

1'\sivezaut + M".si2'

K., Takeda, M., Nakajima, A.. Yoshrr. E .

nucleophilic

2,8,9-Trimethyl- L-phospha- 2,5,8,9-tetraazabicyclo[3.3.3]undecane. Acylation.' This cage heterocycle (1) is an excellent catalyst for the acylation of hindered alcohols. Acetylation is acceleratedin polar solvents (MeCN), but benzoylation is faster in solvents such as benzene.

'r'r-\(

\_^,Ji (1)

Trimethylsilyl azide. 13,24-25:14. 25: 15. . Alkyl azides are ob{arn Organoazides,

by using the Me.SiN.,-BuoNF reagent s\.sten correspondingbromo derivatives in a rertim A cyclic allylic azide is required for a srnd is obtainable from a Pd-catalyzedreaction of ! dicarbonatein the presenceof a chiral ligand

^r-"x QCOOMe

-..-c; :

\

OCOOMe

t.,t {\ ( \ - P d - c r ) Me3SiN3 ligand. CHzClz,rt

Silyhtion'' For tertiary alcohols and hindered phenols, the conventional method of r-butyldimethylsilylationusing TBS-cl fails. A catalytic amount of I with l.l equiv. of EtrN in MecN is able to effect the silylation in high yields at room temperature. 'D'Su, 8.A., Verkade, J.c. JOC 61,2963O99r'. rD'Su, 8.A., Verkade,J.c. ./ACStlf., 12832 .:1996\.

F

i ir1

t

a-Azido ketones.- Alkenes give ttrsc; in dichloromethane at room temperaruret9 er The opening of ftAzido alcohols. The productsm (salen)Cr(Iil)5or PhoSbOH.6

Trimethylsilylazide

{.r-r--rund€cane

rri: r. rrf the hydroxyl group is a favorable

371

(E)-[F-Trimethylsilylacrytoyl]'/-butyldimethylsilane. [4+3]Cycloaddition.r Lithium enolatesof enones,includingo-bromoacetophenone, condensewith the acylsilane (1) to give 3-r-butyldimethylsiloxy-5-trimethylsilylby aldolreaction,Brook likely proceeds This intriguingtransformation 3-cycloheptenones. cyclizationto give a conjugatebaseof 1,2-dialkenyl-1,2-cyclopropanediol rearrangement, monosilylether,andCoperearrangement.

88% (>98%ee) r\ ll /^siM"oBrt l l -

. . \r,'hr.J. Sa 183(1995).

o tl +

rBSo-\_/ 'a

-8oo -> -3oo

Me3si/

l:

"\/

THF

Sitt''te3

(1)

u7"

( ' l lr. 8949(t996). rTuk"du.K., Takeda, A., Yoshii,E. "/ACs117'6400(1995)' M., Nakaiima, 3:: ::.rtron by vicarious nucleophilic rJ.:::t()o nf r-BuoK. t.:-

qq6l

r clo[-l.f .31utdecane. a: :ric.llent catalystfor the acylation of o;:: .,,1\ents(MeCN),but benzoylation is

-380 Trimethylsilyt azide. 13, 24 -25 ; 14, 25 ; 15, 3 42-343 ; 16, 17 ; 18, 379 of alkyl halides reaction by a displacement Organoazides. Alkyl azidesare obtained from the obtained are by using the MerSiNr-BuoNF reagent system.l 2-Azidoimidazoles (PhrP)rPdClr'2 by correspondingbromo derivatives in a reaction catalyzed A cyclic allylic azide is required for a synthesisof (+)-pancratistatin.3This intermediate is obtainable from a Pd-catalyzedreaction of Me,SiN, with a meso-2-cyclohexene-1,4-diol dicarbonatein the presenceof a chiral ligand.

9H

t

QCOOMe

QCOOMe

'^ -f"',./ t / \\ --,,,\o : 0coove

((-eo-cr), Me3SiN3 ligand' CH2C|2,rt

er:.: :henols, the conventionalmethodof . j:.:.r ric amountof 1 with 1.1 equiv. of rs: .:tlds at room temperature.

Ho-r1t'on

o-.'\.'NAox |

1 | 'o\\*"

|

o H o (+)-pancratistatin

a-AZido ketones.4 Alkenes give theseproducts with a mixture of MerSiN, and CrO, in dichloromethane at room temperature(9 examples, 5l-82Va)' The opening of epoxides by MerSiN, is catalyzed by ftAzido alcohols. (salen)Cr(Ill)5 or PhrSbOH.6The products may be hydrolyzed or the silyl ethers isolated.

372

Trimethylsilylazide

ft Azido N -tosy larnines.7 Opening of aziridines on reaction with Me,SiN, is catalyzedby imidochrornium complexes, and the regioselectivity of this reaction is enhanced by molecularsieves. NHTs

No

Ph-

I

Me3SiN3

- nco"f

OAc

'Oriyama, T., Yatabe,K., Sugawara.S.. \l.rhrg 2Trzeciak. A.. Bannwarth. W. S l.l-13 r l9)r. 3Roby, J., Voyer, N. ZL 38, I 9 I ( I 997 r "Procopiou, P.A., Baugh,S.P.D..Flack. S S . lq 5Mo.r.un. C.J..Aube. J. I52,3-10-1rl+16 6Miku-i, K., Kishino, H. TL37.3705 r ler. Tl-ind"r*un. R.J..Chen. S. IL 37. 3tl19 r lcr*' oBoons, G.-J.,Eveson,R., Smith. S.. Stauch,T eHob".g, J.O.,Bozell, J.J. TL 36.68-1I r l+rf r0limori, T., Shibazaki, T., Ikegami. S. n -17 :: "I.hiku*u, J., Miyazaki, S., Fujiuara. \l . \lrnr ''Padwa, A., Harring, S.R., Semones.\t .{ ./(rC

Me3SiOTl

(Triphenylarsonio)acetaldehyde bromil Homologationof aWehydes.' Ertct broughtaboutin oneoperationb1 the rra5

(Triphenylarsonio)acetaldehyde

r\j.:

.r.c'tals bearing an cx,-stannylalkyl

l : - ' . i l \ e s p r o p a r g y l ethers, which are

381

Nazarovcyclization.rr The cyclization of 1,l-difluoro-1,4-pentadien-3-onesI S regioselectivedue to direction by the fluorine atoms.

o

o

I -a^

bromide

Me3SiOTf

B'.'t\',.

il CFz

t \ \ -siMe3 _ .. 2,.. csHrr- "SnBu3

tl rl

""Y

cH2ct2- (cF3)2cHoH

Y

F 73%

870/o

e:: t : D:.

:' based on the reaction of lactol :ltoP 6f the Product is subject to :irc ring. Note that BF..OEt, is not

ft""'\z o-o

L .

In situ prepared N-acetoacetylated alkenyl amides undergo Annulation.'" cyclization to give tricyclic lactams. The catalyzed reaction is considered to proceed by heteroaromaticbetaines. 1,4-dipolarcycloadditioninvolving cross-conjugated

\

f-J*'n \t,Ao

MesSiOTf.

,--

PhcH=cHs\

250 80./.

S r,4e3

Tungsten(Yl) oxychloride-2,6-dibromophenol. Ring-closing metathesis.' WOCI'(OAr), formed in situ with EtoPbform a practical catalyst system for the synthesisof cycloalkenes ( 1I examples, 58-9lVa). rNugent,W.A., Feldman,J.,Calabrese, J.C."/ACSll7,8gg2(lgg5).

.

,.lt ).

:-' lhc'olefinationof ketones.Direction by - ,'r -l-carbonsis observed.The reaction

]R

::J . - 'nrplexesare readily formed as shown

,o",r*\ F

66% (R = H, R' = CsHrr)

fe

it "/..1cs117,2355(1995). zcc.H. SL435(1996).

Ultrasound. 15, 363; 16, 377-379;18, 395 Miscellaneous. N-Acylation of unprotected amino acids,r desilylation of TBS-ethers,2 alkylation of ketone enolates with (iso)/quinolinium salts,s Wolff rearrangement,abromination of active arenes with NBS,5 and dichloroketene formation from Zn and CITCCOCI (for cycloaddition to alkynes)o have all been promoted with ultrasound. Tertiaryalkylacetates.

Usually considered very difficult is the conversion of tertiary alkyl halides to acetateswithout the complication of elimination. The use of both a phase-transfercatalyst and ultrasound apparently favors the displacementby Zn(OAc)r.1 2-Furanylketones.

A synthesis of 2-furanyl ketones using the Barbier technique takes advantageof the facile lithiation of furan by organolithiums. Thus, sonication of a mixture of lithium, t-butyl chloride, a lithium carboxylate, and excess furan in THF accomplishesthe tandem reaction.d

| | Acoon

+

,__l // \\ to/

Vanadium(IL[ID chloride. Reductivecoupling,r Treatingan rnra ketonewith VClr(tmeda),in thepresence of a Homoallylicalcohols.' IV.Cl,rrhfrJ. betweenallyl bromidesandcarbonylcompq lKataoka, Y., Akiyama, H., Makihira, I.. Tan. K . 'Kataoka, Y., Makihira, I., Tani, K. fL 37. 'G,: , t

Vanadyl bis(acetylacetonate). Self-arylationof alkyt aryt sulfides.i I of alkylthioarylaryl sulfidesin excellenrrr undergodealkylationon heatingwith plndrrr

Li-r-tucl -

rHF ))))

Vo(acac)2 - MSOH

At

(CF3CO)2O, BuaNClOl

R

s-

76P/o

f Anuradha, M.V., Ravindranath,B. 253, ll23 (1997). 2lee, A.S.-Y., Yeh, H.-C., Tsai, M.-H. rL 36,6891 (1995). lDiubu, F., Lewis, L, Grignon-Dubois,M., Navarre,S. JOC 61,4830 (1996). -Winum, J.-Y., Kamal, M., lrydet, A., Roque,J.-P.,Montero, J.-L. TL37,l78l 5Paul, V., Sudalai,A., Daniel, T., Srinivasan,K.V. SC 25, 2401 (lgg5). oParker, M.S.A., Rizzo, C.J. SC 25,2781 (1995). ?Juyarr"", J., Rao, J.M. SC26, 1103(1996). 'Aurell, M.J., Einhorn,C., Einhom, J., Luche, J.L. JOC 60,8 (1995).

'Yamamoto,

(1996).

K., Kobayashi, S., Shouji, E.. Tsrhd

Vinyldimethylsilyl chtoride. I,3-Dipolar cycloadditian.t This rcag its reactionwith 4-hydroxy-2-isoxaline 2-orrd tricyclicadducts.

R?,.p-'N'o + .A II .= cooEt OH

l

,,

cl-si---

r-1:-: rmino acids,r desilylation of $' r . o r / q u i n o l i n i u ms a l t s . 3W o l f f t: \uS.: and dichloroketene formation

Vanadium(IUIID chloride. Reductive coupling.r Treating an intermediate preparedby a Grignard reaction of a ketone with VClr(tmeda), in the presenceof a trace of oxygen leadsto a hydrocarbon dimer. Homoallylic alcohols.' [V2cl3(th06]2[ZnrClul is effective in inducing a reaction

Lr.":'.r" have all been promotedwith

between allyl bromides and carbonyl compounds in THF-HMPA.

C .:r difficult is the conversion of h-.:'. ,:r of elimination.The use of both a by Zn(OAc)r.7 l;. '. rhc displacement li r\

f.-r\)nesusing the Barbier technique ::.rnolithiums.Thus, sonicationof a

Lr:-' \\late. and excess furan in THF

re

I r)

tKutuoku, Y., Akiyama,H., Makihira,L, Tani,K. JOC 6L,6094(1996). 'Kataoka, Y., Makihira,I., Tani,K. fL37,7083 (1996.

Vanadyl bis(acetylacetonate). Self-aryhtion of alleylaryl suffides.t Oxidative dimerization gives sulfonium salts of alkylthioaryl aryl sulfides in excellent yields (5 examples, 94-l0OVo). The products undergo dealkylation on heating with pyridine.

Ar-S-R

Ar, +

Vo(acac)2 - MSOH

,slt

(CF3CO)2O, Bu4NCl04

R

R' /=l\

PY,

\--J

A

/f sR

76Ph

94 - l0o% (twosteps)

ClO4

tYa-amoto,

ts

( f:.

s all

hl

r\.10( 1996). 1.1, TL37,l78l (1996). : t995).

.)qi )

Ars

K., Kobayashi, S., Shouji,8., Tsuchida, E. JOC 61, lg12 (1996).

Vinyldimethylsilyl chloride. I,3-Dipolar cycloaddition.t This reagent acts as a l,2-ethanediol equivalent when its reaction with 4-hydroxy-2-isoxaline 2-oxides is followed by oxidative desilylation ofthe tricyclic adducts.

r

R?,o+ *'{A: on

n

' cooEr

/ cr-diI

Nt\ J N H

a2, R'

MeCN R = COOET 79 - >99%

Vinyltriphenylphosphoniurn bromide

tnighi,

P., Marotta, E.,Landuzzi, A., Rosini, G. JACS 1I8,9446 (1996).

Vinyltriphenylphosphoniumbromide. additionof a Grignard Carbonchain stitching.l Th. consecutiveCuBr-catalyzed reagentror phosphonate anion2and Wittig olefinationperformsstitchingof two building blockswith a vinyl groupasthe linchpin.

4Jrn" PhMgBr

CuBr - AgpCO3

* ,r-

oncSr.rnr",

Xenon(ID fluoride. a-Fluoro ethers. The sulfur moieq r featmentwith XeF, (7^examples, 72-854 t Alkenylfluorides,' Thesecompound reactionwith XeF, in thepresence of AgOTf Decarboxylativerearrangemenl] Tna reactionwith XeF, in CHrClr. Interesringll.d reanangement,and the main productsarearED

rshen, Y., Yao,J. JOC 61,8659(1996). 2shen,Y., Yao,J. "/CR(S)428(1996).

rl-u,q., B"nn""he,T. ACS50,850(1996). 'Tius, M.A., Kawakami, J.K. Z5l, 3997( 1995| ''Nongkunsam, P.,Ramsden, C.A. JCS(pl) Ill rl!B

ll\

.:-16(1996).

'r r .:Flr-catalyzedaddition of a Grignard r.r: ,r perforrns stitching of two building Xenon0D fluoride. a-Fluoro ethers. The sulfur moiety of O,S-acetals is replaced by fluorine on treatment with XeF, (7 examples,12-857o). NMe2

(\ Ph

73"k

Alkenylfluorirles.z These compounds can be prepared from alkenylstannanesby reaction with XeF, in the presenceof AgOTf. Decarboxylative rearrangement.l Trimethylsilyl benzoates undergo this radical reaction with XeF, in CHrClr. Interestingly, the reaction in MeCN does not proceed with rearrangement,and the main products are arenesderived from aryl radicals.

r,a".sioocQ{

#

'Lu, T. ACS50,850(1996). Q., Benneche, 'Tius, M.A., Kawakami,J.K. f 51, 3997(lgg5). 3Nongkunsam, P.,Ramsden, C.A. JCS(P1)121(1996).

**#

Ytterbium(Ill)

triflate. 18, 402-403 Cleavage of methoxyacetates.t Thcsc c others (e.g., acetates) in the presence of \-t

Ytterbium. 14, 348; 15, 366:'16, 384; 18, 401 vic-Dialkylatian of thioketones.' Diaryl

thioketones are reduced by Yb in HMPA-THF, and the subsequentaddition of RX introduces alkyl groups at sulfur and the sp2-carbon. Reductivecouplingofcarbonylcompounds. A divalent ytterbium thiolate, Yb(SPh)2,is preparedfrom Yb and PhSSiMe,. This speciespromotes the pinacolization of aromatic aldehydesin acetonitrile or propionitrile (dl: meso, 3-4:l 1.2 Amides are converted to 1,2-diaminoalkenesby Yb-YbIr3 and acylsilanesto alkynes.a

al

Ph

\-^

/'r-" t

THF

\_^

M".si

-"

such as ketene silyl ethers.s N-(cr-aminoaltl imines.6One-pot synthesesof p-amino estcn' Apparent exceptions to simple con&as p-lactam,l0 and the imino Diels-Alder rcarr reaction partner or the other.

Ph

A

r

i

\

*

Yb/ HMPA.THF -10o,

2o min 67"/"

a-Hydroxy imines." is promotedby Yb.

_l

(-rF-" +

OMe NPh

The C-C bond formation betweendiaryl ketonesand isonitriles

+ Ph)

'p h" , Ph

l l,teo^

9^^"n

43%

Ph

Aldolandimino-aldolreactions. .{ \1 Cr-symmetric a,o'-bistrifl amidobibenzr I har t resulting in moderate asymmetric induction L

\-/NJ

Yb - Ybt2

l

methoxyacetateestersas protected alcohols rs Allylation of carbonyl compounds.: \'r reaction, which is mediated by indium in aqrrr Enamination.3 Th" condensarionof al Yb(OTf)3. The catalyst and high pressureharc

Y b / H M P A- T H F -35o:

N

P

h

\ __l-pn \ /

H'

OH

) /-osiw,

Conjugate additions. Indoles reacr s rrh Michael addition in water using p-keroesrcn addition of amines to unsaturated esters ts ft Interestingly, Yb(OTfl3 also promotes radical r

69"/" 'Mukioku, Y., Uebori, S.-Y., Tsuno,M., Taniguchi,Y., Takaki, K., Fujiwara,Y. JOC 61,372 (1996). 'Taniguchi, Y., Nagata, K., Kitamura, T., Fujiwara, Y., Deguchi, D., Maruo, M., Makioka, Y., Takaki, K. TL 37.3465 0990. togu*u, A., Nanke,T., Takami, N., Sekiguchi,N., Kambe, N., Sonoda,N. AOMC 9,461 (1995). -Taniguchi, Y., Fujii, N., Takaki, K., Fujiwara, Y . AOMC 9,371 (1995). 5Mukioku, Y., Tsuno, M., Takaki, K., Taniguchi, Y., Fujiwara, Y . CL 821 (1995).

400

o

3

)t-*AZ.

o.\/'2 l

Ph

't-Ph

YUOrt! iPrl . &.r!9

Er3B q - TlrF CH2C|2

Ytterbium(Itr)triflate

401

Ytterbium(Il)

[: r .' ,rrc. are reduced by yb in n:: ..:...!'\ alkyl groupsat sulfur and the '' Jn alent ytterbium thiolate. .:'-.$ r.. promotesthe pinacolizationof a . ". . , , . . 1 - l :)l . 2 \ - \ hl--l and acylsilanesto alkynes..

_

l

l

triflate. tB, 402_403 cleavage ofmethoxyacetates.l Th.r" estersundergo methanolysis in preference to others (e.g., acetates) in the presence of yb(orf),. Accordingly, the synthetic use of methoxyacetateestersas protected alcohols is broadened. Allylation of carbonyl compounds.2 Ytterbium triflate promotes the allylation reaction, which is mediated by indium in aqueous media. Enamination.3 The condensation of amines with ketones is greatly facilitated by Yb(OTf)3. The catalyst and high pressurehave a synergistic effect. Aaol and imino'ardol reactions. A yb complex prepared from yb(orfl, and a cr-symmetric s,a'-bistriflamidobibenzyl has been used in the Mukaiyama aldol reaction,a resulting in moderate asymmetric induction. Imines are activated toward enol derivatives, such as ketene silyl ethers.5N-(c-aminoalkyl)benzotriazoles are suitable surrogates of imines.6one-pot synthesesof B-amino estersTand ketones8can also be achieved. Apparent exceptions to simple condensations are the formation of quinoline,e B-lactam,r0and the imino Diels-Alder reactions,ll due to a changein reactivity of one reacnon partner or the other.

,NJ .

p

h

*

r^

9,u416

43e;

I

Meo-\

Yb(oT03 MeCN r t , 1 0m i n

I

r-A %*Arn

74%

670/o

n -.. ...rdn diaryl ketonesand isonitriles

OMe I \

NPh

rj

Yb(orf)3

-

ph/

) z

'OSiMe3

MecN

rnTPh'{.\o

rr

937.

-J \{

N

P

h

\ -_l-pn / OH

Coniugate additions' Indoles react with electron-deficientalkenesat the B-carbon.12 Michael addition in water using B-ketoestersas donors grves quantitative yierds.r3 The addition of amines to unsaturatedesters is favored by both the catalyst ani pressure.,o Interestingly, Yb(or03 also promotes radical addition to ry'-enoyloxazolidinones.r5

690/.

rt 1.

r . F u j i w a r aY , . JOC6l,372(1996). . ) . Maruo, M., Makioka, y., Takaki,

\ ,n(da, N. AOMC 9,461 (1995). .,-- 1995). ': ( r.. L 821(1995). \

o

9

,\'AA o. l v'--.

'rPh

Ph

Yb(oT03 FPrl, Bu3SnH Et3B,02 CH2C|2-THF-hexane

j.,I.X

or,i.,

't-Ph Ph 93"/.

402

Yttrium(Ill)isoproPoxide

Glycosylation.r6 Using glucose \,2-cyclic sulfite as the donor the catalyzed glycosylation ofalcohols is Sr2Jike and B-selective' A very favorable effect of Yb(oT03-LioPr' opening of epoxides and aziridines. the ring [the active catalyst is Yb(OPr')r; the triflate itself has too high Lewis acidity] on from prepared readily are 1,2-diamines openings is noted. Thus,2-azido alcohols and respectively. and aziridines.ls epoxidesrT rHanarrroto, T., Sugimoto,Y., Yokoyama,Y., Inanaga,J. JOC 61,4491(1996). 2wang,R.,Lim, C.-M.,Tan,C.-H.,Lim, B.-K , Sim,K.-Y.'Loh,T.-P.fA 6' 1825(1995)' 3Jenner. G. TL37,369l (1996). auotsu,K., Sasai,H., Shibasaki, M. TA 6,71 (1995). sKobayashi, S.,Hachiya'I. 5L233(1995)' S.,Araki, M., Ishitani,H., Nagayama, 6Kobayashi, S.,Ishitani,H., Komiyama,S.,oniciu, D.C.' Katritzky,A.R' fL 37' 3'731(1996). TKobayashi, M. TL36,5173,11995)S.,Araki,M., Yasuda, oKobayashi, S.,Ishitani,H. CC 1379(1995). 'Y. Makioka,Shindo,T., Taniguchi,Y., Takaki,K., Fujiwara,Y. s 801(1995). roAnnunziata, R.,Cinquini,M., Cozzi,F.,Molteni,V., Schupp'O. JOC 6L,8293(1996)' rlKobayashi, S. S I 195(1995). S.,Ishitani,H., Nagayama, r2Harrington, P.E.,Ken, M.A. SI, 1047(1996). "Keller, E.,Feringa, B.L. TL37, 1879(1996). toJ"nn"..G. T 52,13557(1996). rssibi,M.P.,Jasperse, C.P.,Ji, J. JACSll7,10179 (1995)'us-d.r*, W.J.,Kiessling, L.L. TL35,7335(1994)f7M"gu.o,M., Asao,N., Yamamoto,Y. CC l02l (1995). f8M.guro,M., Yamamoto, Y. H 43,2473(1996).

Zeolites.15, 367: 18,405-406 Dehydraion-hydration.t Alkynolspror zeoliteHSZ-360at lower andhigher temperar

/// H. HO

Ph

. / / -.

r{sz-! PhO

(

lrsz-!

HO a 1

gem-Diacetates."'"

Aldehydes af,e coot

zeolites. Cyctizntion.a

Epoxy polyenes undergo c

Yttrium(IlD isopropoxide. Cyanohyd.rinsilylethers.t Yttrium isopropoxide-more likely, the (l-PrO),.YrO (1) to afford a species-complexes with 1,3-bis(2-methylferrocenyl)propane-1,3-dione highly efficient catalyst for the asymmetric silylcyanation of electron-rich aromatic aldehydeswith Me.SiCN.

4A rnd r

cHcl3

Electrophilicalkenylation."

Arenes rq 110'to give I zeolitein l,2-dichlorobenzeneat Both transesterificationi ftKetoesters. diazoacetate?ue catalyzedby zeolites.

'Abiko, A., Wang,G. JOC 61,2264(1996).

Benzoxazolcs.8 Beckmann rearrangerl proceedson heating with HY zeolite at 16O' t 8 Epoxidation of chiral all;-li Oxidation. ZSM-5 zeolite (titanium silicate-l) and c photosensitizedby thiazine dye cation-exchang reaction, only one product is formed.

h . ..rliite as the donor the catalyzed

i.:r o1x$lseffect of Yb(OTflr-LiOP/ : .,. rrro high Lewis acidityl on the ring - Jramines are readily prepared from

l

, tt 6l.449l (1996). \ Lrrh.T.-P.TA6,1825(1995).

Zeolites.15,367: 18,405-406 Dehydration-hydratinn.r $lkynols provideeitherconjugated enynesor enonesover zeoliteHSZ-360at lower andhighertemperatures, respectively.

t i . ,- ::r r. I. 5L233(1995).

(

,

\.,rntzky,A,.R.TL 37,3731(1996).

///

7. HO

..,:.'.\'. S 801(1995). ' 5 . .:n. O. JOC 61,8293(1996).

HSZ.360 Ph

Phct, 65P

lt Ph

gi

// HO

HSZ-360 Phct, 13d

(?i

gem-Diacetates.2'3 Aldehydes .ue converted to RCH(OAc), in the presence of zeolites. .

4

Cyclizntion.- Epoxypolyenesundergocyclizationmediatedby zeolites.

\:

' rJc-more likely, the (l-PrO)'rYrO (1) to afford a ..,propane-1,3-dione

tt

-,. rnation of electron-rich aromatic

44 mol sieves

cHct3 A

-=> =.

-\>

'11 *tx" 70"/.

Electrophilic alkenylation.s Arenes react with phenylacetylene over HZS-360 zeolitein 1,2-dichlorobenzene at 110' to give l,l-diarylethenes(10 examples,40-94Vo). Both transesterification6 and synthesis from aldehydes and ethyl ftKetoesters. diazoacetateTare catalyzed by zeolites. Benzoxazoles.o Beckmann rearrangement of o-hydroxyacetophenone oximes proceedson heating with HY zeolite at 160'(8 examples, 84-95Vo). Oxidation. Epoxidation of chiral allylic alcoholse with vea-H2D2 catalyzed by ZSM-5 zeolite (titanium silicate-1) and ene{ype hydroperoxidation of alkenesr0 photosensitizedby thiazine dye cation-exchangedzeolites have been reported. In the latter reaction, only one product is formed.

404

Zinc

rsartori,G.,Pastorio, A., Maggi,R.,Bigi,F.T 52,8287(1996;). 2Pereira, M.J.,Caneyre,H., Perot,G', Guisnet,M. S 1077(1995). C., Gigante,B., Marcelo-Curto, 3Kurn-,P.,Hegde,V.R.,Kumar,T.P.TL36,601(1995). aSen,S.E.,Zhang,Y.Z.,Roach,S.L.JOC 61,9534(1996). ssurto.i,G.,Bigi,F.,Pastorio, A., Porta,C.,Anenti,A., Maggi,R.,Moretti,N.' Gnappi'G.TL36'9171 (1995). 6nalu;ji, (1996). B. CC'7O'7 M., Kumar,R.,Chanda, n.S.,Sasidharan, 'Sudrik,S.G.,Balaji,B.S.,Singh,A.P.,Mitra,R.B.,Sonawane, H.R.S4 369(1996)' 8Bhawal, A.R'A.S.SC25,3315(1995). S.P.,Likhite,A.P.,Deshmukh, B.M.,Mayabhate, "Adam,W., Kumar,R., Reddy,T.I., Renz,M.ACIEE35, 880(1996). 1\-i, X., Ramamurthy, V. JACS118,10666(1996). Zinc. 13, 346-3 47 ; 14, 349-3 50; 16, 386-3 87; 17, 406- 40'7; 18, 406-408 The preparation of the bis[methyl (s)-lactyl] acetylenedicarboxylater Elimination. involves alcoholysis of dibromofumaryl chloride and debromination with Zn in refluxing T}IF. Asymmetric induction in the Diels-Alder reactions of the chiral diester has been probed. Alkynylsitanes. Silylation of alkynes2and copper(I) alkynidesr is promoted by Zn in MeCN (sealed-tubereactions). Coupling reactions. The hexacarbonyldicobalt complexes of cycloocta-1,5-diynes and cyclooct-3-ene-1,5-diynes have been acquired by reductive cyclization of the dication orecursors.4 Co2(CO)6

Co2(CO)6

/ - . . . .-. .*, ' ' '

I\'-,^Ph I

C02(CO)6

Zn cHzct2 rt,2h

/-t\.Ph

l

\t..:,r/""Ph

l

I

Coz(CO)o 48"k

The coupling of benzyl bromides with organotin derivatives with Zn powder leads to benzyltin compounds.5 Aqueous media are suitable for the allylation of Altylation and propargylatian. p-ketoesters,6 and when a modified B-cyclodextrin is present, the allylation of cyclohexenone shows asymmetric induction (307o ee;] The analogous Barbier-type propargylationofaldehydesalsoproceedsatroomtemperature(l0examples,41-859o)? Allylation of iminese using Zn is comparable to that using Mg. The Barbier-type allylation of aldehydescan be carried out in liquid ammonia.rO Allyl ketones are rapidly formed by the reaction of allyl bromide with acid chlorides in ether.tl y-Nitro esters.t2 The conjugate addition to nitroalkenes with Reformatsky reagens representsa new way for the preparation of the nitro esters.

Ether cleavage,l3 In the presence of i estersand alkyl chlorides. Reduction of sulfuxides.ra A combrne reduces sulfoxides to sulfides at room temp.rr

tch-lton, J.L.,Chee,G.,McColeman. H. CJCt-r 2Sugita,H., Hatanaka, Y., Hiyama,T. fL J6. :-ii) 3Sugita,H., Hatanaka, Y., Hiyama,T. CL -1-9, l+c -Melikyan,G.G.,Khan,M.A., Nicholas. K.\t ()V 'Marton,D., Russo,U., Stivanello,D.. Tagharur-( oAhonen, M., Sjoholm,R. Ct 341(1995r. 'Fornasier, R., Marcuzzi,F., Piva,M.. Torrllar... L' oYavari,I., Riazi-Kermani, F. SC25. 291-1r l99j 'Wang,D.-K.,Dai,L.-X.,Hou,X.-L..Zhang.\' fl toMukorru,M., Grela,K. SC26, 2935( 1996| "Ranu, B.C.,Majee,A., Das,A.R. f4 37. I lll}l , :91 ''Menicagli, t l9c6 R., Samaritani, S. f 52. 142-s ''Bhar, S.,Ranu,B.C.JOC 60,745,l995t. tow-g, Y., Koreeda, M. SL 885(1996).

Zinc, activated, A useful technique for the preparation of a and Cu powders) is by electrolysis u'ith puk

efficiency in allylation achieved by usine >u involves reduction of ZnCl, with Na in hgud , Ketones. Rieke zinc produced b1 tlr n

reacts with alkyl halides, and the org:rnozrtr ' treatmentwith CuCN and acid chlorides Sc readilypreparedin this direct manner.t cr-Chlo

method using chloroacetyl chloride in the crr4 3-Thienylzinchalides.o These reagcru Rieke zinc. They undergo Ni-catalyzed couplu

lDu.unt,A., Delplancke, J.-L.,Winand.R..Rerrsc. I 'Makosza.M.. Grela,K., Fabianowski. W. f 52.9J' 3Hunron, M., Rieke,R.D.SC25,l0l (1995). -Rieke, R.D.,Hanson, M.V., Brown,J.D..Niu.QJ . sRi"k",R.D.,Brown,J.D.,Wu, A.X. sC 25.-191i I Wu, X., Rieke,R.D.JOC 60,6658(1995).

Zinc, amalgamated. Styrenes.' A modified Clemmensen rt some ethanol in refluxing formic acid gives *1'

Fragmentation. Some 3-acetvlclcltrall Clemmensenreduction conditions.

Zinc, amalgamated

l':rot. G., Guisnet,M. S 1077 (1995).

r ii

a {. R . M o r e t t i , N . ,G n a p p i , G . T L 3 6 ' 9 1 1 7

\!,-'( - -

1996). r : - . : : r J .H . R . 5 4 3 6 9 ( 1 9 9 6 ) . u r . : \ R A . S . S C 2 5 ' 3 3 1 5( 1 9 9 5 ) . !r .- ,,1996).

18,406-408 ? - 'r,--107; r . acerylenedicarboxylatd I -!/-lactlll 6..'11 Zn in refluxingTIIF. with .:rhrrrmination rJ (,: ::r. .hiral diesterhasbeenprobed. is promotedby Zn in c' ::.rrr I ) alkynides3 t f

.()mplexesof cycloocta-1,5-diynes rcductivecyclization of the dication

co2(co)6 ,/-VPh I \-'/""Pn I

C02(CO)6 48"/"

x ' ' .rcrivativeswith Zn powder leadsto r:'.i.::.1i.rresuitable for the allylation of n:r\:nn is present, the allylation of . ee).7 The analogous Barbier-type (10 examples,4l-85Vo).8 :J:nperature c

Ether clcavage.l3 In the presence of acid chlorides, ethers are transformed into estersand alkyl chlorides. Reduction of sulfuxides.ra A combination of Zn, Ac.O, and DMAP in MeCN reducessulfoxides to sulfides at room temperature(8 examples,50-97Vo). rcharlton.J.L.,Chee,G., McColeman,H.CJC73, 1454(1995). 2Sugita, Y., Hiyama,T. TL36,2'169(1995). H., Hatanaka, rsugita,H., Hatanaka, Y., Hiyama,T. CL3'79(1996). oMelikyan,G.G.,Khan,M.A., Nicholas,K.M. OM 14,2170(1995). 5Mu.ton,D., Russo,U., Stivanello,D., Tagliavini,G. OM 15,1645(1996). 6Ahonen, M., Sjoholm,R. CI, 341(1995). TFornasier, U. G 126,633(1996). F.,Piva,M., Tonellato, R.,Marcuzzi, oYavari.I.. RiazlKermani,F. SC25, 2923(1995). vWang,D.-K.,Dai,L.-X.,Hou,X.-L.,Zhang,Y.TL37,418'l(1996). r0Mukorru,M., Grela,K. SC26, 2935(1996). rrRanu, B.C.,Majee,A., Das,A.R.TL37,llD (1996). ''Menicagli,R., Samaritani, S. T 52,1425(1996). ''Bhar,S.,Ranu,B.C.JOC 60,745(1995). tow-g, Y., Koreeda, M. SL 885(1996).

Zinc, activated. A useful technique for the preparation of active submicronic Zn powder (as well as Co and Cu powders) is by electrolysis with pulsed ultrasonic irradiation.r Greatly enhanced efficiency in allylation achieved by using such Zn powders is noted. Another method involves reduction of ZnClrwith Na in liquid ammonia.2 Ketones. Rieke zinc produced by the reduction of Zn(cN), with Li naphthalenide reacts with alkyl halides, and the organozinc halides can be used to form ketones on treatment with CuCN and acid chlorides.3Secondary and tertiary alkylzinc bromides are readily preparedin this direct manner.a u-Chloromethyl ketoneshave beenpreparedby this method using chloroacetyl chloride in the coupling reaction.s 3-Thienylzinc halides.b These reagenrs are obtained from 3-thienyl halides and Rieke zinc. They undergo Ni-catalyzed coupling with aryl iodides. rDurant,A., Delplancke, J. TL36,4257(1995). J.-L.,Winand,R.,Reisse, tMukorru,M., Grela,K., Fabianowski,W. T 52,9575(1996). rHunson, M., Rieke,R.D.SC25, 101(1995). oRiek",R.D.,Hanson, M.V., Brown,J.D.,Niu,Q.J.JoC 61,2726(1996). 5Ri"k",R.D.,Brown,J.D.,Wu, A.X. SC25,3923(1995). \Mu. X.. Rieke,R.D.Joc 60,6658(1995).

t : :,, that using Mg. The Barbier-type ig.,::lttttltliS.l0

r, :

l .rllvl bromide with acid chlorides in

tr. :r:::.rrlkeneswith Reformatskyreagens ll:: l\ters.

Zinc, amalgamated. Styrenes.t A modified Clemmensen reduction of aryl ketones using Zn(Hg) and someethanol in refluxing formic acid gives styrenes(E-form major; 5 examples,69-83Vo). Some 3-acetylcycloalkanones undergo fragmentation2 under the Fragmentatian. Clemmensenreduction conditions.

Zinc-aceticacid

4M

Ordinary nitroalkenes give saturared c Zn-CF,COOH in organic solvents.6 Amino acids from N-trichlaroethox-rcot fragmentation of the N-protecting g.roup b\ ; iminium speciesthat are hydrolyzed in srtu

o

"+.-r-.-\

R

Zn-Hg

l

l

HCI/ H2O A

R= H

44o/o

o u ll A '/n ll PhNH' n^

rHiegel,G.A., Carney,J.R.SC26, 2625(1996). 'Bailey, K.8., Davis,B.R.AJC 48,1827(1995).

Zinc-acetic acid. The double bond is saturated to give Reductionofa-oxoketenedilhioacetals. dithioacetals of p-keto aldehydes.r Note that different sets of products are obtained on reduction by the Zn-ZnCI"/TMEDA

znt HoAc-H2o I d--.----*

l

system.2

o sMe Jl I Ph' v -sMe TMEDA

s4'/'

Zn rcrt

cl3c..,r,o.r.,NJ" il o

'Rao, C.S.,Patro,B., Ila, H., Junjappa.H. /./C,8 JS 2Yadav, K.M., Suresh,J.R.,Patro,8., Ila. H . Jun.r{r jBoiuin, J., Laflemand,J., Schmitt,A..7.ard. s z lL -Rani, B.R., Ubukata,M., Osada,H. BCSJ 6t. lli: , l 5Koos, M. TL 37,415 (1996). 6suikiu, A.K., Barua,N.C., Sharma,R.P..GholtL \ ( 7choll"t, J.-F.,Miginiac, L., Rudelle,J.. Bonnemar

o Ph'l^9\sM

e

85%

e

650/"

o

ll PhYsM

Zinc-nickel chloride. Reductionof conjugateddouble bondsvaluablein situationsin whichotherdoublehtro facilitatedwith ultrasound,hasbeenemplored

o BnO

Ph/\\./

Zn l*Ci.l

Reductive desulfurization of o-(2-pyridinethio)sulfones' occurs Desu$urtzntion. removing the thiopyridyl group. Zn-HOAc, treatment with on Benzyl acetates.4 Aryl carbonyl compounds (but not others) undergo reductive

MeOrCt,:

acetylation at room temperature. y-Acetoxy nitroalkenes are converted to unsaturated Reductionofnitroalkenes. is applicable to the synthesisof 2,3-unsaturatedsugars.s oximes, and the method

CHNOa i t CH I AcO-CH I R

Zn - HOAo(H2O)

CH=NOH I CH ll

Et2o

CH I R

penitrem-D

Zinc-nickel chloride

r'> - **'-At

,

,

o

Ordinary nitroalkenes give saturated carbonyl compounds on treatment with Zn-CF,COOH in organic solvents.o Dechlorinative Amino acidsfrom N-trichloroethoxycarbonyloxazolidin-S-ones,1 fragmentation of the N-protecting group by Zn-HOAc triggers ring cleavage to afford iminium speciesthat are hydrolyzed in situ.

?

o

enrrrH^$,"., ct3c.,.z.oYNJ"

o znt HoAc-rr2o

NHz

o hr l,ruble bond is saturated to give ftr.:.:rr s€tSof products are obtained on

b

94'/.

SU:

o Ph

v

-SMe

\,/

'sMe

il Ph

rn^"\coo" 80./.

rRao, IJC(B)358,57 (1996). C.S.,Patro,B., Ita,H., Junjappa,H. 2Yadav, T 52,4679(1996). K.M.,Suresh, J.R.,Patro,B., Ila, H., Junjappa,H. 3Boiuin, Lallemand, J., J.,Schmiu,A.,Zard,S.Z.TL36,7243(1995). *Rani, B.R.,Ubukata,M., Osada,H. BCS"/68, 282(1995). 5Koos,M. TL 37,415(1996). usuikiu,A.K., Barua,N.C.,Sharma,R.P.,Ghosh,A.C "/CR(S)124(1996). 7choll"t,J.-F.,Miginiac,L., Rudelle, J.-L. SC 23,2101(1993). J.,Bonnemain,

Zinc-nickel chloride. This selective reduction method is Reductian of conjugated double bonds.l valuable in situationsin which other double bonds must be retained.Such a reaction, further facilitated with ultrasound, has been employed during a synthesisof penitrem-D.

o BnO

Ph'^t\t/

I

I rr. l:::',

rn,-

: cr.-t2-pyridinethio)sulfones3 occurs

Ao :

MeO(CH2)2OH

ffOUp.

hut not others) undergo reductive

Ao

t.:

I

R

-o -: - 5 - /

)))) 90%

K

l1

lr .:.\.nes are converted to unsaturated sugars.5 l 1.3-unsaturated r...

CH=NOH I CH tl CH

Zn, NiCl2.6H2O

penitrem-D

O

Zinc borohydride

tsmith, A.B., III, Nolen,E.G.,Shirai,R., Blas6,F.R.,Ohta,M., Chida,N., Hartz,R.A., Fitch,D.M., P.A. JOC 60,7837(1995). Clark,W.M., Sprengeler, Zinc-copper couple. 13, 348; 15, 367 -368; 16, 387-388; 17, 407l.18, 408-409 The reduction system consistsof Zn-Cu, BqP, and MsOH. RCOCI -+RCHO.' 1-Alkoxy-1-siloxyclcl.opropanes.z Trapping of the organozinc speciesderived from B-haloalkanoic esterswith a silyl chloride provides the cyclopropanone acetals.

'.../Yo.,\

Z n - C u I T H FA ; FBuMqSiCl

'Narasimhan, S., Madhavan,S., Prasad.K-G. S('L 3Bhattacharyya, S. OM 15,1065 (1996).

Zinc borohydride-aluminum phoephetcEpoxide cleavage,' The supponed h"rr temperature,giving alcohols.

Hydration of styrenes.2 Mixture oi alc secondaryalcohols.

rCampelo, J.M.,Chakraborty, R.,Marinas. J.\t .t(': 'Campelo, J.M.,Chakaborty, R.,Marinas. J.\l ,(('i

I

A".rl,

Zinc bromide.13,349;15, 368: 16. -189--re

OSiMe2Bu' 56%

Imines undergo reductive coupling. In the presence of vic-Diamines.' (+)-10-camphorsulfonic acid, the (R,R)-1,2-diamines are formed. The use of Zn-CuI in DMF to eliminate tclFl from Dehalogenation. a-allyloxy-o-chloroperfluoroalkanoic esters initiates the synthesis of 8,e-unsaturated B,p-difluoro-a-keto estersby a Claisen re,urangementj

Dehydrogenation.' Thearomadzatrtnr Hydroly sis of gem-bis (benzotria?ell l,*a

nitroarenes consists of vicarious nuclctrg l-yl)methane and successivetreatment *rrh Z

ry'^\-t)

,n-( ozruh \:' \---r//--

oo

SnBur Ph r _,2

,[-\ 56"/.

Lr: -iclate to zinc salts,but do not h . ,. ihe problem.

oxetanes.a Allylsilanes form [2+2]-adducts with aldehydes. Unlike reactions catalyzedby many other Lewis acids, this reaction retains the silyl group.

ZtCl4

csHrr--lo

-

\

FBuSiPh2

,o. cun,r-ah

cH2ct2

l-BuSiPh2 530k

[--r::::.tl zirconacyclopentadienes are r. \ CuCl-mediatedreactionof these c. ::\c\ fused aromaticproducts.The

(z)-3'Iotlo-2-(hydroxyalkyl)acrylates.s zrclo mediatesthe reaction of methyl propynoateanda carbonylcompoundin thepresence of BuoNI.This processis analogous to theBaylis-Hillmanreaction,with thedifferencebeingthatiodineis incorporared.

Zirconocene, Zr-alkylated

O

Lcu",'

:cooMe

"",ch* 00,5h

Cyclafunctionalimtion. l.n-Dienc ftr isonitriles. Most significantly, rransdiqurnan with N-allyl-2-bromoanilinesa as a buildrne H

Hor. FC"Hrr

ZrCla- BuaNl

/

I

-

COOMe

84'/.(ZE 73:271

,-o -l

o-Fries rearrangement.6 The rearrangementtakes place at ambient temperaturein the presenceof Z{14 (8 examples,3l-977a). tPutney,H.K., Margan,S. TL 37, 4621(1996). 'Asao,N., Liu, J.-X.,Sudoh,T., Yamamoto,Y. JOC 61,4568(1996). 3Asao, Y. CC 1513(1996). Y., Yamamoto, N., Matsukawa, oAkiyurnu,T., Yamanaka, M. 51-1095(1996). szhang, C.,Lu, X. S 586( 1996). oHarrowven, D.C.,Dainty,R.F. TL 37,7659 (1996).

A- o X \

I

Cp2ZrBu2 -78o-> rt

| ..,'-o

l 'X | L

\7

n

LO'"-f H

Cyclization of a l,7-diene derived from o-r the zirconacycle, leads to a diol, which can hc kinetic product is the isomeric cls-fused zrrcan

CpzZtCl2- BuLi

Zirconium(IV)

triflate. Azidolysis of eporides,'

The opening of epoxide to give 2-azido alcohols may employ 1,1,3,3-tetramethylguanidiniumazide in the presenceof Zr(OTf)..

PhMe A;

o

rCrotti.P.,Di Bussolo, M. TL37,1675(1996). V., Favero,L., Macchia,F.,Pineschi,

Zirconocene, Zr-alkylated. 15, 81; 18,414 Organozirconocenechlorides add to aliphatic and Alkylation-oxidation ,rqu"rr".\ aromatic aldehydes(ZnBrrcatalyzsd). Oppenaueroxidation occurs when the reaction time

OBn O2i

H2O+

1

o

is prolonged.

Oz(Cp)2Cl

ZnBr2 CsHfiZr(Cp)2Cl

t

+

PhCHO THF, 25O

crn,r

en

HzO .*

oH

".".,r4r^

(Alkenyl)chlorozirconocenes.6 The ree gives good yields of alkenylzirconocenesI obtained by hydrozirconation methods.Such zl

acyl chlorides, and allyl halides in the presenr-c to achievea direct coupling in a one-potprorcr

3h

| ,n""o, u n

88"/"

I

o

tl c6tt17Aen

G1"

Cpzzt8,i

83"/"

Treatment of an alkyne with CprZrR, and then ethyl vinyl ether furnishes a diene. If iodine is used in the finial quenching, an iododiene results. 7,3-Dienes.z

Allyl ethers.' Alkenyl(chloro)zirconcr-cl and CprZr(H)Cl react with cr-chloro erhers.u hc to increasethe reactivity. Allyl ethers are prorJu

Zirconocene,Zr-alkylated

cyclofunctionalimtion. r,n-Dienesform zirconabicycles, which allow insertionby isonitriles.Most significantry,trans-diquinanes areobtainedfrom 1,6-dienes.3 cyclization with N-allyl-2-bromoanilinesa asa buildingblock is alsoa usefultransformation,

HO \-c"H,, - ' / I

413

COOMe

84/o (ZE 73:27\

tE:: :riie\ place at ambient temperafure in

il : rl

f r-"V-h,.^'l | /Y651-''"0' H

L

!

rscH2Nc. \ai

]=)L.x:p=" 46%

1996).

cyclization ofa r,7-diene derived from c-terpineol, followed by oxidative creavageof the zirconacycle, leads to a diol, which can be converted to (+)-elemol.s Interestingry, the kinetic product is the isomeric crs-fusedzirconabicycle.

' r:. r:,le to give 2-azido alcohols may rr ::i'\ence of Zr(OTf).. \r rL37,1675(1996).

E:

a< \a\-\

OBn

(+)-elemol

OBn l z : : - :rrcene chlorides add to aliphatic and

;.rrion occurs when the reaction time

'l

)Zr(Cp\>Cl I I H'o 'Ph !-

]---* PhcHo / 6 h

OH

I

crH,r

Ph

88V"

lt c..- -

(Alkenyl)chlorozirconocenes,6 The reaction of 2-halo- l-alkenes with cprzrBu, gives good yields of arkenylzirconocenes. These are regioisomers of those products obtained by hydrozirconation methods.Such zirconocenesare usefurfor coupling with ArI, acyl chlorides, and allyl halides in the presence of a pd(0) cataryst and ZnCr'r.It is possibre to achievea direct coupling in a one_potprotocol.

'Ph

83%

ic Cp.ZrR, and then ethyl vinyl ether rr.. hing, an iododieneresults.

1)rl \--N.

,\

Cp2ZrBu2

e, Jr

'ZrCp2

I

br

cl 92%

Allyl ethers.T Alkenyl(chloro)zirconocenes that are readily obtained from alkynes and cprZr(H)cl react with cr-chroroethers,when znCrrisused as a transmetailatlngagent to increasethe reactivity. Allyl ethers are produced.

414

Zirconocenedichloride

lzheng, B., Srebnik, M. JOC 60,3278 (1995). "Iakahashi, T., Kondakov, D.Y., Xi, 2., Suzuki, N. JACS ll7,5871 (1995). 3Davis, J.M., Whitby, R.J.,Jaxa-Chamiec,A. TL35,1445 (1994). +tietze,L.F., Grote, T. Joc 59, 192 (1994). 5Taber, D.F., Wang, Y. TL36,6639 (1995). oTakahashi, T., Kotora, M., Fischer, R., Nishihara, Y., Nakajima, K. "/ACS 117, 11039 (1995). TPereira, S., Zheng, B., Srebnik, M. JOC 60,6260 (1995).

Zirconocene hydrochloride. 14. 8 l : 15. ErrReduction of lactones and anhydridct-' for subsequentconversion into bisalkorrphrrt

fto LO

Zirconocene dichloride. 14, 122; 15, 120-l2l ; 18, 4 15 With CprZrCl2 to promote the crs-alkylalumination of alkynes Alkylalumination. with &Al, alkenylaluminums are obtained. Reaction of the latter with o-acetoxy-o-benzylideneaminoacetic esters constitutes a key step in the synthesis of (Z/-B.lunsaturatedamino acid derivatives.r

R: Me3Al

Y

HzNrcoon'

PhrNYcooR

AlMea CpzztCl2

I

ph

R

OAc

(Ph3P)aPd;

HCt/ Et2O

Y

lCp2Z(H)clln

lzrlo/

THF

Allyl ethers." Hydrozirconation trf al\r in the presenceof ZnCl, gives (E/-allr I ethcn Thioallylation.3 Allylzirconium ip61 carbonyl compounds in an antl-selectire fa{l (E ) -2 -Alke ny l- 1,3,2 -dio xab oro Min cs.

borationof l-alkynes with pinacolborane.'dt q-bromo ketones.5

R

When a modified zirconocene dichloride (1) in which each Cp is replaced by the chiral 1-neomenthylindenylgroup is engagedin the methylalumination, the alcohols isolated after oxidation are optically active.2

MqAl / CICH2CH2CI

O2

CoHrg,^.,

Y o H :

+

'

0o->rt. I h

"ur,Vro-o.

caHtV

-

., o-./ \ I

X

A

Col'tt A.C

(

{

Hydroboration of alkenes is similarll r:ca CH2CI2 to CCl4, the producr-s fn 1,1,1,3-tetrachloroalkanes.6 These tuo rcr (Ph"P).RhCl.

88% (727" ee)

(1)

3-Attcylidenetetrahydrofurans.3 The low-valent zirconium speciesgeneratedby the reduction of CprZrC!, with Mg reacts with allyl propargyl ethers to form the zirconabicycles. On protonolysis, the alkylidenetetrahydrofuransare obtained. rO'Donnell, W.D.,Grote,T.TL35,9383(1994). M.J.,Li, M., Bennett, 2Kondakov, D.Y., Negishi,E.-I.JACSl1i7,lo77l (1995). 'Miura,K., Funatsu, M., Saito,H., Ito, H., Hosomi,A. TL37,9059(1996).

(

Zirconocenehydrochloride

4ls

Zirconocene hydrochloride.14,8l; 15,80-81; lg.416_417 Reductianoflactonesand anhydrides.r In this reactionbisalkoxidesareproduced for subsequent conversioninto bisalkoxyphosphines.

lr-'.

\ , / { c s 1 1 7 I. 1 0 3 9d 9 9 5 ) .

1-'r'o

lcp2z(H)Clln

Ph2PCl

rzrlo'\i\"otzd

THF

-U

0 o - > r t . 1h

X.

t n-

' -. :,-alkvlaluminationof alkyrrs i:.:;tion of the latter *ith . ., ker step in the synthesisof

nzrurcoon k

t*:P)aPd,

Y

nnreO'\t"A"'OPPh'

-78o -> rt 't2 h

Allyl ethers,' Hydrozirconation of alkynes followed by reaction with c,-chloroethers in the presenceof ZnCl, gives (E)-allyl ethers ( 17 examples,45-92Vo). Thiaallylation.r Allylzirconium species derived from allenyl sulfides react with carbonyl compounds in an anti-selectivefashion to give 4-hydroxy-3-sulfenyl-l-alkenes. (E)-2-Alkenyl-1,3,2-dioxaborolidines. prepared by CprZr(H)Cl-catalyzed hydro_ borationof l-alkynes with pinacolborane,a thesecompoundsare usefulfor the synthesisof cr-bromo ketones.s

R

CaHte,.n t7 r^-O t:

t,

D

r x o-/ \ /\

r.rch Cp is replaced by the chiral nrtion. the alcoholsisolatedafter

Br I

Cp2Zt(H)Cll Cl+Ctpi \ , /

A

Accl.cuBr2.SMe2: NBS

CzHrs ll O 89%

-

COH1a,r'.

Y

o :

H

Hydroboration of alkenesis similarly accomplished.When the solvent is changedfrom CH2CI2 to CCl4, the products from I -alkenes are the homologous 1,1,1,3-tetrachloroalkanes.6 These two reactions are more efficiently catalyzed by (PhjP)3RhCl.

88'k (72"/. ee)

MeosiM?'oV

ox'

.'::ionium speciesgeneratedby the r-... rropargyl ethers to form the al . i:,,turansareobtained. r:

Q i. :

l9g_{).

720k

.

tttessiry

.

HB'o. t

6*^ /\ nrla^ai

'

Y'

I

_r' , jer1996). 720/o

uul3

416

Zirconocenehydrochloride

The alkenylborolidines undergo facile boron migration during hydrozirconation.TThus, the B-isopropenyl derivative gives the l-propylborolidine on aqueous quenching and the 3-borolidinylpentyl methyl ketone on reaction with MVK.

?'oy

ox'

AUTHORINDEX

4'r

/ 2* Cp2Zr(H'yCl

lY o

870/"

a-Allenic boronic esters.s Hydrozirconation of alkenylboronic esters in CH2CI2 gives the gem-borazirconaalkanes,which can be used to couple with propargyl bromide. The s-allenic boronic esters thus obtained react with aldehydes to afford 2-( I -hydroxyalkyl)-1,3-dienes.

ta\

**?-v ox' Primary

amines.e

HoYR'

\\

I R*a-ol,,

| 2* Cp2zr(H)Ct

Br'

Hydrozirconation

O-(mesitylenesulfonyl)hydroxylamine (E)-Alkenylchalcogenides.

o f +

CUCN

of

l -alkenes

.v\

"J

R'cHo

followed

by

reaction

with

provides primary amines (10 examples, 62-88Vo).

The alkenylzirconocene

chlorides

are converted into

selenidesr0 and telluridesrr by reaction with organochalcogen halides. rcenac, N., Zablocka, M., Igau, A., Majoral, J.-P., Skowronska, A. JOC 61,:796 (1996). 2Pereira, S., Zheng, B., Srebnik,M. JOC 60,6260 (1995). 'Chino, M., Liang, G.H., Matsumoto,T., Suzuki, K. CL23l (1996). "Pereira, S., Srebnik, M. OM 14,312'7 (1995). 5zheng, B., Srebnik,M. TL 36,5665 ( I 995). oPereira, S., Srebnik,M. JACS f 18, 909 (1996). TPereira, S., Srebnik,M. JOC 60,4316 (1995). oZheng,B., Srebnik,M. JOC 60,486 (1995). "Zheng,B., Srebnik,M. JOC 60,1912 (1995). 'oHuung, X.,Zhu,L.-5. JCS(PI ) 76'l (1996). "Sung, J.W., Lee, C.-W., Oh, D.Y. Zr 36, 1503 (1995).

Abajo,T.M.,363 W.,361 AMelqader, H.,285 Abdel-Rahman, A b e ,H . , 1 1 0 l,1 l , 1 4 1 Abiko,A., 126,402 Abiru,K.,275 AbreuDias,8., 125 M.M.,217 Abu-Omar, Achiwa,K.,91,187,191 Adachi,K., 340,366 Adachi,M.,34 Adam,H.,53 Adam,J.,48 Adam,W., 136,188,218,404 M., 188 Adamczyk, Adams,J.,203 Adibi,M.,219 Adlington,R.M.,11,366 Adrio,J.,357 Aesa,M.C., 1,385 Afonso,M.M.,48 G.R.,22 Afsharifar, Aggarwal,V.K., 92, 215,285,302 Aguirre,J.M.,312 Ahiko,T.,5 Ahman,J., 196,353 Ahmed,G., l3l Ahn,J.H.,45,312 Ahn,Y.-G.,339,3M Ahonen,M.,405 Ai,H.,315 Aihara,H., 168,292,296 AirMohand,S.,314 Aizawa,M.,216 Akai,S.,59,361 K.G.,13 Akamanchi, M.,387 Akazome, Akimoto,T., 145 Akita,H.,235 Akiyama,H.,240,397 Akiyama,T.,344,412 Aksoy,H.,338 Akula.M.R.,43

Dr. [}i

:: I s h\ drozirconation.T Th[s. I :rlueouSquenchingand d|c

X

AUTHOR INDEX g'o",/

o-\

c f'

'.ifrronic esters in CH2CI. :ic irith propargyl bromide. :th aldehydes to afford

HoYR' c

R'cHo_ 4 R . /

c\ a: ea X.

'ilowed by reaction with .. ( l0 examples,62-88Vo). -hlorides are converted into :.rlides. ,)( 61.796(1996\.

Abajo,T.M.,363 Abdelqader, W.,361 AMel-Rahman, H.,285 A b e ,H . , 1 1 0 1 , ll , 1 4 1 Abiko,A., 126,4O2 Abiru,K.,275 AbreuDias,8.,125 Abu-Omar, M.M.,217 Achiwa,K.,91,187,191 Adachi,K.,340,366 Adachi,M., 34 Adam,H.,53 Adam,J.,48 Adam,W., 136,188,218,404 Adamczyk, M., 188 Adams,J.,203 Adibi,M., 219 Adlington,R.M.,I l, 366 Adrio,J.,357 Aesa,M.C., l, 385 Afonso,M.M.,48 Afsharifar, G.R.,22 Aggarwal,V.K., 92,215,285,302 Aguirre,J.M.,312 Ahiko,T.,5 Ahman,J., 196,353 Ahmed,G., 13l Ahn,J.H.,45,312 Ahn,Y.-G.,339,344 Ahonen,M.,405 Ai, H., 315 Aihara,H., 168,292,296 Ait-Mohand, S.,314 Aizawa,M.,216 Akai,S.,59,361 Akamanchi, K.G.,13 Akazome, M.,387 Akimoto,T., 145 Akita,H.,235 Akiyama,H.,240,397 Akiyama,T.,344,412 Aksoy,H., 338 Akula,M.R.,43

Al Dulayymi,J.R.,161 Al-Abed,Y.,309 Alami,M., 27, 59,ll0 Alcaraz,L.,267 Aldea,R'244 Alesso,8.N.,312 Alexakis,A.,235 Alexander, C.W.,61, 109,235 Allard,C., 157 Allen,D.G.,247 Allin,S.M.,20 Allred,G.D.,I l2 Al-Masum,M., 392 Alonso,8.,193 Alonso,J.J.P., 284 Aloui,M., 175 Alper,H.,27, 114,179,210,223,244,26'7, 281,392 Alper,P.B.,365 Alvarez,R.M., 363 Alvarez-Builla, J.,3, 22,96 Alvaro,G., 235 Alvisi,D.,255 Aly, M.F.,95 Amadji,M.,90 Amanfu,J.,330 Amatore,C.,242 Amer,F.A.,I78,307 Amishiro,N., 377 Ammon,H.L.,322 Ananthan, S.,69 Anderson, C.E.,65 Anderson, J.C.,330 Anderson, W.K.,48 Andersson, P.G.,251 Ando,H.,263,314,372 Ando,K., 144 Ando,N., 19l Ando,Y.,238 Andreotti,D., 59 Andres, C.J.,216 Andres,J.M.,9l Andrews, D.M.,92

41E

Authorlndex

Andrews,I.P.,268 M.A.,264 Andrews, Anenti,A.,4(X R., 315 Angelaud, Angeft,H.H.,242 Angle,S.R.,1214 Anker,D.,48 Anna,L.J.,235 R.,402 Annunziata, Anoune,N.,244 Ansari,M.A., 1l I Antenori,M., 106 Antus,S.,270 M.V.,396 Anuradha, Acn,K.l.,24 Aoki,H.,321 Aoki,K., 175,365 Aoki,M., 167 Aoki,Y.,59 Aoyagi,Y., 296 Aparicio,D.,4 Apelquist,T., 304 Apodaca,R., 375 C.D., 307 Apostolopoulos, Appel,W.K., 147 Appell,R.B.,246 Arai,H.,122 Arai,M.,9l Arai,N., 69 Aril,T.,24 Araki,M.,402 Araki,S.,6,172,173 Araneo,S.,306 A., 134 Arasappan, Arct,J.,266 Arime,T., 296 Arista,L., 53 Armstrong,J.D.,128 R.W.,260 Armstrong, Amaud,C.,244 Amone,A.,264 Amswald,M., 349 Aronica,L.A., 157,228 Arora,J.,91 Arrastia,I., 201 Arrayas,R.G.,357 Arterbum,J.8., 359 H., 267 Arzoumanian, Asada,D., 196 Asaka.S.-I.,222

Asakura,C., 334 Asano,J.,201 Asano,K.,296 Asao,N., 10,12,67, 91, 144,228,359,402,412 Asensio, G.,219 Aspris,P.H.,62 Astruc,D., 105 Y.,238 Atarashi, Atherton,M.J., 146 Atkinson,R.S.,I Aube,J.,17,48,381 Aubert,C., 119 Auge,J.,203 Auirion,l.-C.,62 Aumann,R., 101 Aurell,M.J.,191,396 J.M.,296,299 Aurrecoechea, Avendano,C., 106 Avilov,D.V.,90 Axon,J.R.,9l Aznar,F., 101 Azuma,Y., l0 Azzena,U.,59 Baan,G., l, 385 Baba,A., I'74, 240,263,338,358,372, 375 Baban,J.A.,98 Babler,J.H.,275 Bach,J.,93 Bachki,A., 193 Back,T.G.,9O,27l J.G.,48 Badiang, Badudri,F., 155 Bae,J.G.,161,346 M.C.,284 Bagley, W., 133 Baidossi, Bailey,K.8.,406 Bailey,W.F.,62,63 Baine,N.H.,375 Baird,M.S.,l6l Bak,R.R.,18 Bakhtin,1.C.,271 Bakstad,E., 267 Balaji,B.S.,404 T., 267 Balakrishnan, Balaux,8.,299 Balazs,L.,263 Baldino,C.M.,136 Baldwin,1.C.,235 Baldwin,J.E.,11, 207,366

E.S.,365 Balenkova, A., 101 Ballesteros, M., 169,393 Ballestri, Ballini,R., ll'1, 136,267.313 Balme,G.,267 Balmer,M.K.,377 ch,E., 241 Balogh-Hetgovi B.P.,45,314 Bandgar, Banerji,A., 34t) Banerji,P., 120 W., 381 Bannwarth, Banwell,M.G.,365 Bao,W., 173,291,296.299 Baracz,N.M., 180 LL., 365 Baraznenok, A.,235 Barbero, Barbero,M., 169 Barbry,D.,309 Barco,A., 183 Barden,M.C.,40,347.3'18 Bardot,V., 173 Y., 170 Bareket, V.,313 Bargues, Barker,E., I l0l, ll0 Barluenga,J., C.L.,201 Barnes, Barnier,J.-P.,284 M.I., 162 Barrena, l-17."l A.G.M.,91,92, Barrett, P.A.,95 Barsanti, Barth,L.,69 Bartoli,G., 192 Barton,D.H.R.,I I I, 169 B a r u a , N . C1.1, 1 , 4 0 7 B., 11,65 Baruah, Baruah,J.B.,106 M., 180 Baruah, D., 12 Basavaiah, A.R.,377 Bassindale, R.W.,251 Bates, Batista,A.C.F.,129 Bars,J.W.,102,123 Battle,W., 128 169 Batts,8.D., Baud,C., 285 J.-8.,48 Baudin, Baugh,S.P.D.,381 A.L., 136 Baumstark, Bauta,W.B.,69 Bayne,C.D.,181

Authorlndex :Ll

t-

f: ).,1

_

.

\i\ :+ \ . I :. 67. 9 I , t44, 228, 359, 402, 4t2 r. (, ll9 i:

rP::

t,'t :,S rf. \1 J. l-16 tr Ri.l J

.-:\.-181

L (

e

.

J : : ! - ' I

6 :

E. k

:rrl

, \l .i

iel.396

clc.':"

J )1..296,299 ,. . ll)5 '' efl . :l , R -: rc.

F

:

,

.\

: r-i

i.

-:

, l{

:J0, 263,338,358,372,375

,.

H

:-.:

).: . ".i

-.

{ ltl | (l -lr l.

.( l

;

'_.

b{

:-