Fiesers' Reagents for Organic Synthesis

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VOLUME TWENTY

Tse-LokHo

PUBLICATION A WILEY-INTERSCIENCE WILEY & SONS,INC. JOHN / TORONTO / SINGAPORE NEWYORK/ CHICI{ESTER / \\iEINHEIM/ BRISBANE

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PREFACE rffi#FS z'fttIJEl*

For a task perfectlY done First have the tool sharPened

The above is a Chinese saying that emphasizesthe importance of having good tools to the successof various endeavors.In organic synthesis,the improvement or sharpening of the pertinent tools is the development of new reagentsand/or reconditioning of existing ones' The aim of this seriesis to gather the scatteredtools and put them in order. On this occasionof publication of Volume 20 of Fiesers' Reagentsfor Organic Synthesis in the year 2000 (XX/MM), I wish to reflect on the monumental publication launched in "Volume l" did not appear in that title, so that the series 1967. Wasn't it fortunate that 'Volume One"' (these "It is bad luck to title a book survives to this day? As it has been said: words are attributable to the mathematician-philosopherGian-Carlo Rota, if not earlier writers). However, everyone could foresee the longevity of the series from its inception, sinceits value is so apparent. While I count my blessings for the privilege of continuing the work from Volume l8 onward, an overwhelming uneasinessprevails in my mind due to the relentless increaseof synthetic reagentsand methodologies.On examination of this volume the reader will notice particularly the unabatedactivities in organometallic chemistry, and therefore, a great number of entries deal with metallic reagents(palladium' samarlum, indium. titanium. zirconium, etc.). The same can be said about chiral catalysts and auxiliaries. Perhapsthe coverage of all variants on the same theme, for example, the use of metal salts that have different counterions and require additives or ligands for the same transformations, may not serve the best purpose, but finding an alternative solution without prominently deviating from the original format is hard' The practice of many chemists publishing papers that have no significant differences in contents makes the abstraction all the more difficult. More seriously, many purportedly new results have already been reported. That such reports escaped detection and were published is not rare, and I have no qualms at ignoring those, both for the sake of fairness and keeping the size of the volume in line. TsE-Lox Ho

CONTENTS

GeneralAbbreviations ix ReferenceAbbreviations xiii Reagents I Author Index 447 Subjectlndex 511

vll

rF

GENERAL ABBREVIATIONS Ac acac

acetyl acetylacetonate

ADDP

1,1'-(azodicarbonyl)dipiperidine

AIBN

2,2'-azobisisobutyronitrile

aq

aqueous

Ar

aryl

Bn

benzyl

Boc

t-butoxycarbonYl

Bu Bz

n-butyl benzoyl

18-c-6

18-crown-6

c-

cyclo cerium(IV) ammonium nifrate

CAN cat Cp

catalytic

Cy

cyclohexyl

cyclopentadienyl

DABCO 1,4-diazabicyclo[2.2.2]octane (diethylamino)sulfurtrifluoride DAST DBN

1,5-diazabicyclo[4.3.0]non-5-ene

DCC

N,M-dicyclohexylcarbodiimide 2,3-dichloro-5,6-dicyano-1,4-benzoquinone diastereomerexcess

DDQ de DEAD DIAD DIBAH DMAP DMD

diethylazodicarboxYlate diisopropylazodicarboxylate diisobutylaluminum hydride 4-(dimethylamino)pyridine dimethyldioxirane

DME

1,2-dimethoxyethane

DMF

N,N-dimethylformamide

DMPU DMSO

MM-dimethylpropyleneurea dimethyl sulfoxide

dppb

1,4-bis(diphenylphosphino)butane

dppe

1,2-bis(diphenylphosphino)ethane

dppf dppp

1,2-bis(diphenylphosphino)ferrocene 1,2-bis(diphenylphosphino)propane

E

COOMe

ee

enantiomerexcess tx

x

GencralAbbreviations

Et

ethyl

EVE

ethyl vinyl ether hexamethylphosphorictriamide

HMPA hv

light

Hx

n_hexyl

Ipc

isopinocampheyl

i-Pr

isopropyl

kbar

kilobar

L

ligand

LAH LTMP

lithium aluminum hydride lithium diisopropylamide lithium 2,2,6,6-tetramerhylpiperidide

lut

2,6-lutidine

LDA

M

metal (alkali)

MAD

methylaluminumbis(2,6_t_butyl_4_methylphenoxide)

R' {\) SA\tP *ns. TB.{F TBDPS TBS TL\IPO TES THF Thr

nPs T}IEDA Tlts T

MCPBA n-chloroperoxybenzoic acid Me methyl Ms mesyl (methanesulfonyl) MTO

methylrhodiumtrioxide

MVK NBS

methyl vinyl ketone N-bromosuccinimide

NCS

N-chlorosuccinimide

NIS

N-iodosuccinimide

NMO

N-methylmorpholineoxide

NMP

N-methylpyrrolidone

Np

Naphthyl

Ns

p-nitrobenzenesulfonvl

Nu

nucleophile

Oct

octyl

PCC

pyridinium chlorochromate pyridinium dichromate

PDC PEG

polyethylene glycol

Ph

phenyl

Pht

phthaloyl

Piv

pivaloyl

PMB

p-methoxybenzyloxymethyl

Pr

n-propyl

py

pyridine

Q* RAMP

quatemaryonium ion (R)-1-amino-2-merhoxymethylpynolidine

RaNi

Raney nickel

i

l

lh-:r-*L,

j

l

,r

rl

GeneralAbbreviations

Rr (s) SAMP sens. TBAF TBDPS

perfluoroalkyl solid (.9)-l-amino-2-methoxymethylpyrrolidine photosensitizer tetrabutylammoniumfluoride t-butyldiphenylsilyl =TBDMS, r-butyldimethylsilyl

TBS TEMPO 2,2,6,6-tetramethylpiperidinoxy triethylsilyl TES THF

tetrahydrofuran

/-hexyl=1,1,2-trimethylpropyl triisopropylsilyl TMEDA N,N,MM-tetramethylethylenediamine trimethylsilyl TMS tosyl (p-toluenesulfonYl) Ts

Thx TIPS

A ))))

heat microwave

xi

-t

REFERENCEABBREVIATIONS ACIEE ACR ACS AJC AOMC BBB BCSJ BRAS BSCB BSCF CB CC CCCC CEJ CHJC CJC CL CPB CR DC EJIC EJOC G H HC HCA HX IJC(B) IJS(B) JACS

#

t

Angew. Chem. Int. Ed. Engl. Acc. Chem. Res. Acta Chem. Scand. Aust. J. Chem. Appl. Organomet. Chem. Biosc. Biotech.Biochem' Bull. Chem. Soc.JPn. Bull. Russ.Acad. Sci' Bull. Soc. Chim. Belg. Bull. Soc. Chim. Fr' Chem. Ber. Chem.Commun. Collect. Czech. Chem. Commun. Chem. Eur. J. Chin. J. Chem. Can. J. Chem. Chem. Lett. Chem. Pharm.Bull. Carbohydr. Res. Dokl. Chem. (Engl. Trans.) Eur. J. Inorg. Chem. Eur. J. Org. Chem' Gazz.Chim. Ital. HeterocYcles HeteroatomChem. Helv. Chim. Acta Huaxue Xuebao Indian J. Chem.,Sect.B Int. J. Sulfur Chem.,Part B J. Am. Chem. Soc.

J. Carbohydr. Chem. JCCS0) J. Chin. Chem. Soc. (Taipei) JCR(S) J. Chem. Res.(SYnoPsis) JCS(PI) J. Chem. Soc. Perkin Trans. 1 JCC

JHC

J. Fluorine Chem. J. HeterocYcl.Chem.

JMC

J. Med. Chem.

JFC

xlll

rF

ReferenceAbbrtviations

JNP JOC JOCU JOMC LA MC NJC NKK OM OPPI PAC PSS RTC RJGC RJOC S SC SL SOC T

J. Nat. Prod. J. Org. Chem. J. Org. Chem. USSR (Engl. Trans.) J.Organomet.Chem. Liebigs Ann. Chem. Mendeleev Commun. New J. Chem. Nippon Kagaku Kaishi Organometallics Org. Prep. Proc. Int. Pure Appl. Chem. PhosphorusSulfur Silicon Recl. Trav. Chim. pays-Bas Russ.J. Gen. Chem. RussianJ. Org. Chem. Synthesis Synth.Commun. Synletr Synth. Org. Chem. (Jpn.) Tetrahedron

TA

Tetrahedron:Asymmetry

TL

TetrahedronLett. Youii Huaxue

YH

Reage

Acetic anhydride. to a pyrazole on ffraZole from xylose,t The phenylosazoneof o-xylose is converted refluxing with AcrO. Ring contractian on acetylntion.2 3-Acetyl-2,3-dihydrobenzothiazoles are formed efficiently (10 examples, 65-80Vo) from 2,4-diaryl-2,3-dihydro-1,5-benzothiazepines under acetylating conditions. Acetylati.on. Rapid peracetylation of carbohydratescan be effected in the presence of iodine.3 With more iodine and longer reaction times the selective acetolysis of primary benzyl ethers is achieved. Perbenzyl ethers of mono- and disaccharidesundergo group exchange (OBn -+ OAc) at the primary carbon atoms4 on treatment with AcrO-HOAc-ZnClr. gem-Diacetatesare formed from aldehydesat room temperaturein high yields when the or AcrO-MerSiCl-NaL6 ordinary alcohols latter are treated with Acro-HoAc-znclrs undergo acetylation with AcrO-MerSiCl in MeCN or CH2CI2.7 'Di"hl, V., Cuny,E., Lichtenthaler, F. w. Il 48, 1193(1998). 2Toth.G., Levai,A., Balazs,B., Simon,A. I-4995 (1997). 3Kutthu, K. P. R.,Field,R. A. I53, 11753(1997). aYang,G.,Ding,X., Kong,F. rL38,6'725(1997) 5D"ku,N., Kalita,D. J.,Borah,R.,Sarma, l. C. JOC 62,1563(1997). 6D"ka.N., Borah,R., Kalita,D. J.,Sarma, 94 (1998)' J. C. ,ICR(S) TKu.arer*uran,R.,Gupta,A., Vankar,Y.D. SC27'2'17(1997).

Acetylacetonato(dicarbonyl)rhodium. Arylation of aldehydes.\ Aryl group transfer from arylboronic acids to relatively electron-rich aldehydes can be accomplished in aqueous DME by using the (acac)Rh(CO)r-dppf catalyst system. Michaet addition.2 The B-aryl or B-alkenyl group of an organoboronic acid is transferred to enones in the presenceof (acac)Rh(CO), and dppb. Yields usually exceed 8OVo. tsakui,M., Ueda,M., Miyaura,N. ACIEE37,32'19 (1998). :Sukai,M., Hayashi,H., Miyaura,N. oM 16, 4229(1997). 4-Acetylamino-2,2,6,6-tetramethylpiperidine-1-oxoammonium perchlorate' The reagent is an efficient oxidant, particularly in the presence Alcohol oxidation. However, detonation of an 8-g sample while drying (20 96-loo7o).t examples, of silica gel I

Alkenyl aryliodonium tetralluoroborates

at 55o under high vacuum has been reported. The corresponding tetrafluoroborate salt more stable.2 tBobbitt,J.M. Joc 63,9367(1998). 2Bobbitt, J. M. C&ENJuly19,6 (1999).

l{ .rl

1-Acetylimidazole. Acetylation.t Primaryalcoholsand phenolsare selectivelyacetylatedon grinding 48-96Vo). with thereagent(15 examples,

L

r|

lHagiwara, I., Kato,M. SC28'2001(1998)' T.,Ando,M.,Yamamoto, K.,Suzuki, H.,Morohashi,

\t =a

Acylgermanes. Cyclopentanones.t Radical cyclization to generateA-germylalkoxyradicals is followed by rapid fragmentationto afford ketoneproducts.Structuralfeaturesusually thusbicyclizationcanoccur. dictatethefragmentation,

i:-t /'/&::'^, Ph

6_(o",* ^b.

l ^ (+r" L .

l*

39"

rcu.run,D. P..Diederichsen, (199'1). 119,4797 M. "/ACS U.,Palovich,

Lrd

*r

'ft!

N-Acylpyridinium salts. are Acylationof chiral alcohols.t The pyridinium triflates and tetrafluoroborates alcoholssuchascr-hydroxy for deliveryof acyl groupsto chiral secondary usefulreagents carboxylicesters.

rl

twugne., W.,Anders, E. S883(1998). R.,Giinther,

ral

lit

rql

Alane. Cleavageofcarbamates.r 0-Stannyl alcohols protectedas carbamatesundergo the carbamates Sn/Li exchange.After reactionof the lithiatedreagentswith electrophiles canbe cleavedwith AlH, in THF. rchong, (1998). N. IL 39,9617 J.M.,Nielsen, Alkenyl aryliodonium tetrafluoroborates. Alkenylationof 1,3-diketones.t Enolatesof l,3-diketonesundergo alkenylation with thereagents.

\q "i:r

knrr

-

Alkenyldihaloboranesandalkynyldihaloboranes 3

It r:

ro"hiui,

M., Shu, T., Nagaoka, T., Kitagawa, y. JoC 62,2130 (1997).

l - ( 1-Alkenyl)benzotriazoles. a-Ketols.t These enaminesare converted to cx-ketolsvia epoxidation and hydrolysis with perchloric acid in refluxing THF. rKatritzky,A. R., Heck,K. A., Li, J.,Wells,A., Garot'C. SC26'2657(1996). drng

I

Alkenylboronic acids. involves reaction of the f,y-Unsaturated *amino acids. A practical synthesis (11 54-967a\.tAn analogous examples, benzylamine and boronic acidswith glyoxylic acid alcohols'2 to anti-1,2-amino leads reactioninvolving cr-hydroxyaldehydes

rl. ts uelir

Bn'l.,l''

^Ph . 1 v, , 8 ( o H ) z * B n N H M e * o * " Y t u t + p / \ , / V c s H r r EroH 6n 6, 84"/"

ketones.3 Alkenylboronicacidstransferthe organicresidues a,p,y',6'-unsaturated member)in the presenceof cyanuric dienones(at the lesssubstituted to cross-conjugated fluoride. 'Petasis, N. A., Zavialov,I. A. "/ACS119,445(199'l). 2P.tu.ir,N. A., Zavialov,L A. JACS120,11789(1998). rHara,S.,Shudoh, S.,Suzuki,A. BCSJ7l' 2403(1998). H., Ishimura, C\ tre fdr()\\'

Alkenyldihaloboranes and alkynyldihaloboranes. Diels-Alder reactions. The dihaloboranes are available from alkenyl- and by treatmentwith BX3 (X = Cl, Br). In alkynylsilanes,rand the correspondingstannanes2 situ condensationwith dienes furnishes cycloadducts.

lx]crgo amates

Il

l\ iatlon

BBr3

-SiMe3

;;

:nlaerz

NaoH.

)\)

HooH ."\,"

aBBt2

ll

Y

lsingleton, D.A., Leung, S.-W. JOMC 544, 15'l (199'l) 2leung, S.-W., Singleton,D.A. JOC 62,1955 (1997).

\^l-o*

4

Alkylchloroboranes

Alkenyltitanocenes. Carbonyl compounds are converted to allenes on reaction with Allenes.t alkenyltitanocenes( I 6 examples,40-897o).

..USCc

.^ta

gr\ e r\nRrrn!

Meo CHO +

ll_, iCPz

rHF +

//

\__

Meo-\

F1 /f

t-.{lty}l tE>! rmnrdl .rc-rmrcl

f

MeO 887"

hr:ssrn rPetasis, N., Hu, Y.-H.JOC 62,782(199'1).

N-Alkoxycarbonylimidazoles. Mixed estersof carbonic acids,r A one-pot preparation of mixed carbonic estersis achievedby sequentialreactionswith two primary alcohols. 'Bertolini, Pavich,G.,Vergani,B. JOC 63,6031(1998). G., l-r.-xt

chlorides. (N-Alkyl-N-alkoxyammine)dimethylaluminum N-Alkoxyamidine salts.t The Al salts obtained from reaction of Me.Al with N-alkoxyamine hydrochlorides at low temperaturereact with nitrile to give the substituted

rlt r-.{l

amidines.

i\.Glanx

'Singh,S.,Nicholas, K. M. SC27, 4021('1997).

1nt

F

N-Alkylbis(trimethylsilylmethyl)amines. The amines generate 1,3-dipoles under electrochemical conditions. Pyrrolidines.t

r.}rd

The reactive speciesare interceptedby alkenes.

{rta

lTorii,S.,Okumoto,H., Genba,A. SL2l'r (1994).

: rltto l: cr-q

Alkylchloroboranes. fonolidines.t pyrrolidines.

Homoallylic

Ng

, ^,/\,4

n1su7

azides react with

the chloroboranes to

I.r-ifr.

(

r.tht

Thexyl-B(H)Cl ;

NaOH

afford

,tt HrsCz,"'

(

F!€ilt ld

rSulrnon, A., Carboni,B. JOMC 567,31(1998).

\ rn.{|q

'!

urr

l,-

AllYlbarium reagents

\\ Ith

5

Alkyldichloroboranes. Ald'olreactions.'Enolateformationfromketonesandsubsequentaldolreaction give syn-aldolsstereoselectively' lRamachandran, P.V.,Xu,W'-C',Brown'H' C' IL 38'769(199'l)' bromides' 1-Alkyt-1-phenylphosphoranium - '-' .lhe phosphoraniumsaltsarepreparedby alkylationof thephosphine d;-;;;;;;r.l correspondingphosphine oxide. The immediately after its generationfrom the stereoselectivityoftheWittigreactionwithArCHoisverysensitivetothebaseused. is thepreferredbasefor obtaining(E)-styrenes hexamethyldisilazide Potassium

a^)

)'a

il('f' ls

(MesSi)2NK R'CHO

/'R

ll- R '

rla*."n"", N. J.,Beynek'H. SL497(1998)' \l \\ lth |rrlluted

';;;;;.izes. reagents. Allytaluminum '*' r propargylaluminum reagents Reaction of ketimines with allyl- and constitutesaconvenientpathwaytothetertiaryamines(l4examples'46.94Vo)' 'B*bot, F.,Miginiac,L. SC27,2601(199'7)'

ndltl()ns.

Allyl ' azide. iii.inrr,t

of NaN, with allyl bromide Allyl azide is readily preparedby reaction

inwatercontainingBuoNBr.HydrolysisafterreactionwithArLiorArMgBraffordsArNH' ( I 3 examPles,52-837o)' I

.rfford

'Kabalku,c. w., Li, c. TL38,5'7'1'7 (1997)'

Allytbarium reagents. increased in the The cr-regioselectivity of this reaction is Homoallylic alcohols.t presenceof a crown ethet' obtained as the major products' Reaction with epoxides.2 4-Alkenols are lYanagisawa, H' sL 1090(1997)' Y, Yamamoto' A., Yamada, (199'1)' tv^r"J, f., Yanagisawa, A', Yamada'Y'' Yamamoto'H' BCSJ70' 493

6

Allylindiumreagents

Allylboron reagents. In the presenceof a chiral ligand the reaction of triallylborane Homoallylic amines,\ homoallylic amines. in chiral results N-silylimines with reactions of B-allyl borate complex derived from Pd-catalyzed couplings.z suzuki aryl triflates give allylarenes.This technique with B-methoxy-9-borabicyclo[3.3.I]nonane to allow transfer of Me, TMSCH, and alkynyl coupling of the Suzuki scope broadensthe groups which has eluded conventional manipulations. 1,3-Diols.3 Direct methallylation with methallylboronic

acid

has been

demonstrated. rltsuno.S.,Watanabe, A. A., Sarhan'A. A. ACIEE 36,109(1997)' K., Ito, K., El-Shehawy, 2Fii.rtne.,A., Seidel,G. SL 161(1998). 3Brzezinski, L. J.,Leahy,J. W. TL39,2039(1998). I

Allyldicarbonylcyclopentadienyliron. The allyliron complex reacts with Methyltetrahydrofuran-3-carboxylales.t which then undergoescarbonylation system the heterocyclic furnish to compounds carbonyl under CO. methanol in with CAN on treatment

I {

rJiang,S.,Turos,E. TL35,7889(1994).

s I

a

complexes. (r13.Allyt)dicarbonylnitrosyliron y-Aminoqpunsaturatedesters.' The iron complexes react with amines (e.g., BnNHr) to furnishtheesterproducts.

I .l

t

rNakanishi, S., Okamoto,K., Yamaguchi,H., Takata'T. S 1735(1998).

I

Allylindium reagents. from indium powderandallyl I,4-Dicnes.r The allylindiumsRrInrI, aregenerated alkynes(10 examples' functionalized iodideandusedin situ to addto unactivatedand/or

I

a

60-94Vo).

{

a

Ph

r '|

l l * l n' 3c l a

+

rlr

THF 94o/o

Addition to cyclopropenes.2 Addition of allylindiums to the more substituted carbon atom of the double bond is observed.Carboxyl and hydroxymethyl groups have directing effect.

'|

t;l

||]1.

t**t

h.

v Allylsilanes

\\

1 a Y

ro*

I ih)rane

c"Hrc< reJ trom c\ hnique t r . L rn Y l l\

treen

c:. rvith pnr..rtion

7

CoHrg

95% tFuiiwara,N., Yamamoto,Y. JOC 62,2318(199'7). 2Atuki,S.,Nukano,H., Subburaj,K., Hirashita,T., Shibutani,K.' Yamamura, H., Kawai,M., Butsugan, Y. rL39,632't (1998).

Allylsamarium halides. Allylsamarium bromide formed in situ (Sm + allyl bromide) Diallylcarbinamines.t generate the carbinamines (7 examples,66-BIVo). adds to nitriles to 3-Butenamides and 3-butenethioamides." A sfaighdorward synthesis of these amidesis by addition of allylsamarium bromide to isocyanatesand isothiocyanates,respectively. Homoallylic alcohols.3'a Allylsamarium reagents prepaled in tetrahydropyran are quite stable (in THF Wurtz coupling occurs, therefore the Barbier technique must be employed). The sequential procedure made possible by change of solvent gives cleaner products as side reactions such as pinacol formation from ketones and decarbonylation of acid chlorides are avoided. Becauseofthe low basicity allylsamarium reagentscan be used to allylate allyl acetoacetate.

In('. le.g.,

r rnd allyl e\.rrnples,

rYu,M., Zhang,Y., Qian,C. SC27,1495(199'7). tYu, M., Zhang,Y., Qian,C. JCR(S)256(1998). rHamann-Gaudinet, B., Namy,J.-L.,Kagan,H. B. IL 38,6585(1997). aHamann-Gaudinet, B., Namy,J.-L.,Kagan,H.B. JOMC567'39 (1998).

Allylsilanes. Allylchlorosilanes are conveniently obtained by cross-coupling of Preparation.l allyl chloride with polychlorosilanes in dimethylimidazolidinone using zinc as mediator. Catalyzed allylation of a-iodo acetals with leaving group dependence Allylatians. on the Lewis acid has been reported.2Formation of N-tosyl allylamine by reaction of an allylsilane with (N-tosylimino)phenyliodinane is promoted by cu(oTf)r.3 Halide displacementof a polyhalidea occurs in the presenceof CuCl' o-Bis(allyldimethylsilyl)benzene (1)5 is an effective allylating agent for carbonyl compounds in the presenceof BuoNF.

Az"y1 u:.J carbon re Jrrecting

\A,,V (1)

+

PhCHo

Bu4NF + THF oo

OH I /Vrn 1oo%

8

AllYlsilanes

-rf-*!

The conjugate addition

diallylsilane

t:"lli:-":"i::"::Ti"; of a 2-silvlmethvlpent-4-en-1-vt ."*in

PolYfunctional

Jt for the construcuon reagent is very useful

catalYzed bY SnCIo and bulky allylsilanes reaction between aldehydes alkenes to involvesaredox^step'/ ^"'"'d^nnutoao,,.' ., ,-i-.r-:rdna reacrs with electron-deficient *1'.;:::,;:;;Jllactams at low Auyldimethvltrirylsilan: conjugatedllacr the reaction with bicyclic ;;;";"t' afford silylcyclopentanes'

comPounds.o t'' ii-on'rr.uu'

H;;;

,\tr hqgd r

.{| r d ai\1m

ritnn

derivatives' ieaosmaintyto cvclobutane

-'t?O

I

Tict4

//\*O l i l \./

z)''i,n.

cH2cl2

-^-L..-\ | t I )""sicen. \ \,4-r H

L a5%

. l-h tEb

ftHvdroxvethv!*:::':n::1i,1"J$",,u;:ilyLi'l'#:lL'l:JI

e Grienard reagent whlcn the HOCH2CH' moiety' or"i"." contain

Mg/THFA; PhCHO

t

*'?\^

*or'1tn OH OH

65%

Enolate formation'

Trichlorotitanium

and aldehydes are enolates of ketones

The enolateformatron obtainedfromthec,-iooo"*uonylcompounds."".1"...*.withallyltrimethylsilaneand for aldol reactions'r0 useful st;-";;;';; titanium(IV) chloride' protocolisbasedontfttoU'"tutlonthatthereagentcombinationconvertsp-iodoacetates to alkenes.2

lf?!,! ?f;X, l-*::J J,fl "i"ifi,, *:r;I; TE:'ffii .lll*it*:;m*;";W*i ilfti#13:'i,,,, t D Y" chansS'K'' Kim' ''[".]il.'i., anoi'J S"Rhie' ( (ree8). .ilir*i ni.."r:ita,s.BcsJ70.30ssl9e7)'. . -,,^K. rL 39,3177

n tLr I oI

I q rl

Fs {41 C

.}1il#i.t'**?:'*,:,'T'i:r,i'"il'l'l iffi's^lfr .J .l

loMaeda, K'. Shinokubo' H

Allylstannanes 9

u.lng a m.tlonal b1 SnClo Lene: to rn. Jt low

Allylstannanes. A preparative method involves zinc-mediatedcoupling of allyl halides with Bu,SnCl in liquid ammonia.r Atlylations. The reaction of tetraallylstannanewith carbonyl compounds2or acetals3 is mediated by solvents such as MeOH. Acceleration by phenol has been noted.4 In the asymmetric allylation (with a BINOL system), the enantioselectivity is improved by the addition of MeOH.

OMe

SiO2 / MeOH

l4"o'

nJ.' torms r:l:lon the

100%

in acidic aqueousmediasWith During allylationof aldehydeswith tetraallylstannane by CF3CH2OH increased is I the rate dramatically such as 1,8-bis(allylstannyl)naphthalenes chlorides.T with allyl(butyl)tin undergo allylation dueto its Bronstedacidity.6Diketones

f

S nBu2 P h

T",

CH

(1) lehrdes are rl.rlane and le forrnatlon (\Jo aceBtes

The addition ofallylstannanes to glycal cr-oxidesprovides an entry to B-C-glycosides.s The reaction is catalyzed by Bu,SnOTf. In the presence of AIBN in refluxing benzene, conjugate addition of allylstannanes containing electron-deficient substituents to enones (6 examples, 58-697o)e and displacementof cr-haloalkyl sulfones to give homoallylic sulfones (8 examples,7O-907o)t0 may be effected. Fluorous allylstannanes such as (C6F13CH2CH2),SnCHrCH=CH,react with aldehydesthermally,rr the organic and fluorous products can be separatedon a silica gel column which hasbeen treatedwith fluoroalkylsilyl chloride. Using MeCN aseluent the organic products are eluted, while fluorous products and starting material are subsequently removedby hexaneelution. S-Iodomethylisoxazolidines.lz Treatment of the MerSiOTf-promoted cycloadducts of allyltributylstannane and aldonitroneswith NIS completesthe synthesisof the substituted isoxazolines.

Allytzinc bromide .{lrilid

o ffi;"'i ;': 5ru #ffi?ft Li ;Y:!'.I'l;ftd:*n r, ;irXtil;,i"r'; r' ; * t* "FrD;r llj !':,' :1X' :'ni,*'., M' Fujibavashi' (innrt' ) Yasuda' tMukorru,M., Grela,K' SC23'2697(1998)'

Ca rom ra

J . J O C 6 2 , 1 9 6( 1 19 9 7 ) '

i*:if:n:,t,X?ll'R:*;'Jdiii;l ;:;';:;";;'

cr-3JTUIT lc:.vrs I

Baba'A Joc 63'6401(1998) H' s' 1309(1997)' H'' Yamamoto' 5Yanagisawa, A., Morodome' '' Nakashima'

lrIJtI1-(

'i#:;"';;,

K' sL37'trts?81-.N.,i""' Z''Maruoka'

re.r-JOaL

t;;;;,;.:ilvanelro, D ' ragliavini' G' J)MC s40."17^(1ee'7)' 170e(1ee8)." t;;;rb.;" B. irotter, w', Cot"' B'rL3e' 32' 9]L E'rL P epnhol., E. J.,Moran,K. M., whitlev' !1998) 38' leesr.leez)' rL M Petrini' tt;;;;;;,;.' R'' ciovannini, "E"?ir", O t.' nadida'S'' He'M' JOC 62' 6'714(r99'l)' " (1998)' r2cianotti,M., Lombardo'M'' Trombini'C'TL39' 1643

:.(rr!{ro L J:TUII'

Ori ::asrnLi r\ Jn\Il :n*ro !:'-r.n

sulfonesbv a allvl transferfrom allvl entofdithiocarbonates't..The to C-glycosides' radicalprocessopensa route

nu}T;t;:;

,-oAc

AIBN

^^n-1JzO, e ^1;o}*"ps

\:(

heptane

ra:'rf

A

Eto

*b\"saturated condense with carbonYl methyl arenesulfinates' ..tf,yi"n"i.iptenylphosphorane with Chiralsulfoxidesareaccessible' compounds. PhcHo

* Ph3P=CH2 + Tol-S(=O)OMe

-

Ph3P=CHS(=O)To|

Ph \:. \ O=s-Tol

ine' In the

88% -J ' Penaud-Darcy' A' JOC 63'9116 W'' Omelanczuk' J ' Cristau' H Mikolajczyk' M., Perlikowska' (1998).

.,rf Ported . , . , ; er n t i s

o:. DMF is g..sJel).

^""#;;i;:#Trnnodnrr.'

Reaction or

the organolead reagents with

to followed by saponification leads 1-ethoxycarbonyl-2-phenyl-4'5-dihydrooxazol-5-one oxazolone with 75-987a)'similar treatment of the .V-benzoylcr-arylglycines 18 "*u*pl"'' the cinnamyl glycines' r D- styryllead triacetatesaffords

),-r(to"t. // \\ r(\o^or,

ArPb(oAc)g ' "ri*I-o' cHCt3. H ryridine };",

I

NaOH, HzO, D; H+

Biaryls'Arylleadtriacetatescouplewitharylboronicacidsby(dba),Pd,-CHCl,' aod hr..c.ters, T:.c Products

CuI,andNaoMe'ThecriticalroleofNaoMeisintheformationofArPb(oMe).tofacilitate that (dba)tPd'-CHCI' and thence the coupling' Note oxidative addition with Pd(O)' at room temperature'3 catalyzesthe homocoupling of ArPb(OAc)'t :Koen,M. J.,Morgan,J, Prnhey'J T ' Sherry'C J.'JCS(PI)48'7(199'7)' tf""g' s.-f., nyu' g'-C" Son'H'-J'sL 771(1998)' 27' 1893(1998)' 'Kane, U ' ett"' C ' Choi'S -C ' Kim' J'-S SC S.-K.,Shivkumar,

\HPh

I- - c t r-t "

3-Aryloxaziridines' oxidationofsulfi'des.|Underhighpressure3-aryl-2-t-butyloxaziridinedeliverstts

*ttil,T;:r:;;;t"!*!)ionon: r.i:"l-fled to the c::,,nalsoworks

rransrer or

the tRooc-Nl sroup or

is very to nitrogen' carbon' and sulfur nucleophiles \-alkoxycarbonyl-3-aryloxaziridines and sulfilimines' respectively' facile to give hydrazines,keto amines'

(199'7)' JCS(PI)3491 rShimizu,M.,Shibuya,I',Taguchi'Y''Hamakawa'S''.Suzuki'K''Hayakawa'T' (1997)' J'-C' Aubry'A ' Collet'A' CEJ3'16917 :t'idul,J.,Damestoy, s'' c'v,i'' Hannachi'

o-Bc

s-Bcn ct ru.rr+icr

Baker's yeast. Reducti.ons,

An enantioselective reduction of symmetrical diacetylarenes (e.g., 2,6-diacetylpyridine)l is accomplishedwith baker's yeast.o,-Functionalizedketonessuch as l-methanesulfonyl-2-alkanones2 and p-keto esters3 give chiral alcohols. Significantly' baker's yeastgrown under limited oxygen effects reduction to selectively furnish o-hydroxy esters, whereas on slow addition of the keto esters to ordinary yeast in the presence of gluconolactonethe r--hydroxy estersare produced. with engineered baker's yeast and lcyclodextrin Baeyer-Vitligeroxi.dation,4

Brtcrq

!

2lfg

and 3-substitutedcyclopentanonesafford chiral lactones. tu.hiyu*u, M., Katoh,N., Mimura,R., Yokota'N., Shimogaichi, Y'' Shimazaki'M', Ohta'A' ZA 8' (199'7). 3467 2Maguire,A. R., Lowney,D. G. JCS(Pl) 235(1997)'Dahl,A. C.,Madsen, J. O. TA9, 4395(1998). 4Kuyre.,M. M., Chen,G.,Stewaft, J.D. JOC 63,7103(1998).

fr

rrir srcfF( _r -rd.rj

I

{gti iaranr llo(

Barium hydroxide. Cyclization of ureas containing an ester group occurs on microwave Hydantoins.r inadiation using barium hydroxide as a base. Under solvent-free conditions the microwave CrossCannizztroreactians'2 inadiation of a mixture of aldehydes with formaldehyde and barium hydroxide gives alcohols. rGong,Y.-D.,Sohn,H.-Y.,Kurth,M. J. JOC 63,4854(1998). 2Va..^. R. S..Naicker,K. P.,Liesen,P. J. TL39,8437(1998).

L3rft

\

S. B

ftm.q

Barium perchlorate. Glycosyl phosphites are activated by barium perchlorate under Glycosylation.l (in solvents). organic neutral conditions ts"hene.H., Waldmann,H. EIOC 1227(1998).

Barium permanganate. Activated dicnes.r Allylic alcohols are converted to dienes on oxidation and subsequentcondensationwith stabilized Wittig reagentsin situ' tshuto,S.,Niizuma,S.,Matsuda,A. JoC 63,4489(1998). l8

2-L! ::.fr.-'.rh : " .ir'!tca

!

Benzeneselenenylchloride 19

Stable arenedinzonium sahs.t Diazotization of arylamines in the presence of o-Benzenedisulfonmide provides stable salts which can be obtained in a dry state (20 examples,85-99Vo).

O2 S\ NH

, a na s antl\'. dr()\y lcc of nn l-

. 118

O2 FC5H11ONO +

ArNHr-

HOAC

/"rs, t i l

vr\s/

O2

N

ArNi

O2

85 - 990/.

'Barbero, P. S 1171(1998). M., Crisma,M., Degani,I., Fochi,R.,Perracino,

Benzeneselenenylbromide. 13, 26-27 ; 18, 29 Allylic alcohols undergo a highly stereoselective anti-1,3-Methoxyalkanols.r benzeneselenomethoxylationwhen exposedto PhSeBr in methanol. 2,6-Di-t-butylpyridine is added to scavengeHBr. Azetidines.2 Cyclization of homoallylic amines to form azetidines is initiated by selenylation of the double bond.

NHBn !\\;lve

PhSeX / Na2CO3 MeCN

n\\\ ilve

510/"

(x = cl, B0

: gl\ eS

'Kim, K. S.,Park,H. 8., Kim,J. Y., Ahn,Y. H., Jeong,I.H. TL37,1249(1996). :Berthe,B., Outurquin,F., Paulmier,C. TL38, 1393(1997).

: lnder

Benzeneselenenylchloride. 13, 26-27 ; 14, 27; 16, 19-21 ; 17, 26; 18, 30 Introduction of a carbonyl group to the p-position of 2-Acyltetronic acids.t a-acyl-y-butyrolactones is accomplished by reaction with PhSeCl and oxidation with hydrogen peroxide.

o tl ir'n and

al^rn

PhSeCl/ EtOAc;

bAo

HOOH - THF

o 9 \-Aon ( l toAo

51"/.

IF

-.

20

Benzenethiol

909 (1997)' lMittra, A., Yamashita, M., Kawasaki' I'' Murai' H'' Yoshioka' T'' Ohta' S' SL

Dct t rull-onam

K-CO. rn

trifl ate' Benzeneselenenyl Deselenorunctionaliwtion.|PhSeoTfisusedtoactivateselenidesforattackby MeCN a selenideis convertedto an acetamide' Thus,in aqueous nucleophiles.

.\a1aL \t -\ldrgrer" \ ut-i. P ( -$6urnn-

lTineoli, M., Tiecco' M., Testaferri' L'' Temperini' A CC 1883 (1994)'

anhydride' 15' 18 Benzeneseleninic and 1,2-diarylethanesare oxidized to the 1,2-Dinrylethanediones't Both stilbenes at 120o,often in good Yields' with [PhSe(=o)J'oin chlorobenzene cr-diketones

Bcnri-d M :n-rfiatrg \t-!

Q.

Bcomi

rlo

? (PhSe)eO,

::r.rlrCf I .: THF I

Phcl

1200

,\'-ro -i!a(r(nal

52'/"

lcluyton, M. D.' Marcinow'Z, Rabideau'P' W' fL 39' 9lZ'7(1998)'

D\ISO b rp.\i -r'c{\xJfl

r TO*l r -..trJrtrort

BenzenesulfenYl trifl ate' """ziir"rr^"": by phSorf and rhe process Hindered thioglycosides are activated pennits the direct formation of B-mannopyranosides' tc.i.h, D., Sun,S.JACS120'435(1998)'

\-lc::rlr "l-r:!ri).

.

,\-rc:Ctf\

-

Ut-frrrl

\-,rr 1-Benzenesulfonyl-4-trimethylsityl-2-butene' -*;',;:;;;;;;;rr.' (E)- or (Z)-isomer] Alkylation after lithiationof the butene leither gives ('01-1'3-alkadienes' followed by treatment with TBAF

-13'O181

tr::r

H' JOC 63'4181(1998)' rMeagher, T. P.,Yet,L'' Hsiao,C'-N'' Shechter'

-329; 19, 19 Benzenethiol. 16, 32'7 PhSH and KtCO, of phenols from their alkyl ethersusing c.";;; Deprotection. thiolate'' in NMP obviates preformation of the particularly from benzothiazo-Z-ylsulfonyl sulfonamides,2 Liberation of amines from benzenethiol and a base' with treatment derivatives,3can be achievedby

L n i \

o

E

lll-Benzotriazol-l-ylmesylate

2l

Desulfunylation.a An accessto N-alkyl cx,-aminoesters involves alkylation of the sulfonamides and removal of the sulfonyl group by exposure of the products to PhSH, I!CO, in MeCN at room temperature. f,,: .tttackbY ts

r\:Jr,/adto the ld-

rNayak,M. K., Chakraborti, A. K. Zr 38, 8749(lgg7). 'Maligres,P. 8., See,M. M., Askin,D., Reider,P. J. fZ 38, 5253(1997). 'Wuts,P. M., G. Gu,R. L., Northuis, J. M., Thomas, C.L. TL39,9155(1998). -Bowman, (1997). W. R.,Coghlan, D. R. 753, 1578'7

Benzimidazolium dichromate. Oxidalion.t Alcohols are oxidized in an inert solvent (e.g., CClr) under microwave irradiation for a short period (12 examples,73-98Vo). rMeng, Q.-H.,Feng,J.-C.,Bian,N.-S.,Liu, B., Li, C.-C.SC28, 1097(1998).

Benzotriazole. 1,3-Diarylacetones.r A two-step synthesisof theseketonesfrom arylacetyl chlorides involves formation of the N-acylbenzotriazolesand treatment of the latter with excessNaH in THF at room temperature. N-(wCyanoalkyl)sulfonamides.2 Admixture of an aldehydeand a sulfonamide with benzotriazole at room temperature followed by treatment of the adducts with KCN in DMSO leads to the title compounds in good yields. (p-Nitroaryl)diarylmethanes.t A general method for the preparation of these compounds consists of the reaction of diarylmethanols with benzotriazole in the presence of TsOH in a perfluorocarbon fluid under reflux, and treatmentwith nitroarenesunder basic conditions. a:ri the process

:Katritzky, A. R.,Soleiman, M., Yang,B. HC7,365 (1996) -Katritzky,A. R.,Oniciu,D. C.,Ghiviriga,l.SC27,907(1997). .Katritzky, A. R., Toader,D. JOC 62,4137(1997).

lfil-Benzotriazol- 1-yl mesylate. N-Mesylation.r Selective mesylation with 1 in DMF at room temperaturehas been demonstrated.A primary amino group undergoesmesylation in preferenceto a secondary

r - , , rr z ) - i s o m e r ]

amine. Only N-mesylation of amino alcohols with this reagentis achieved.

N

)rrr

N OMs Pf : ti and I!CO, u".','-l-r'lsulfonyl

+

RNH2

+

RNHMs DMF

(1) (1999) Kim,S.Y.,Sung, N.-D.,Whoi,J.-K.,Kim,S.S.TL40,11'7

6 0- 8 7 /

22

periodate 1'Benzyl-4-aza'1-azoniabicyclo[2'2'2]octane

isocyanide' to TsCHTNC in the Benzotriazol-l-ylmethyl This reagent is comolementary with Imidazolesanil pyrroles't RePlacing aldimines ;;t;t"t' bY condensationwith imidazoles of fo*Jon alkenesgivespyrrotes' electron-deficient

(7rra .t:t.]ft'

.n

\ulr

:a

al

fh:a\t -':ir:i\.r

{

44'6'7(1997)' rKatritzky,A. R', Cheng'D ' Musgrave'R 'P' H

-.ir::rt:f -:ir :rr

{

hexafluorophosphate' into Benzotriazol.l-yloxytris(dimethylamino)phosphonium derivatizes carboxYlic reagent 'acids This Activationo\'o'AoxylXo'id''

Lsll

carboxyphosphoniut*uft'*t'itnut"tu'""''ibletoreductionbyNaBHotogivealcohols (1 1 examPles,80-99Vo)' rMcceary,R. P'TL39'3319(1998)'

Benzotrifluoride. """"ir^rrir"r.t

I I

\.{ ]l|ir

\

-{tli

Ia

f--, nrer

dichloromethane i n.o 66 _?oo\ is ap a ootential substitutefor -29') is phCF3 Op 102",mp

asa solventfor manYreactions' log^*u,A.,Curran' D'P'JoC62'450(1997)'

(}-laryl. L'€

iln

T:lca

f.r!ftf CEI netEr.

borohydride' t9' 22 .rt,i, l-Benzyl-4'aza-l'azoniabicycto[2'2'2loctane p.imino sulfoxidesefficientlyin uo.iya.io" r ,u*.u."* sulfoxu)J! ftAmino manner(10 examples'80-93Vo)' a highly diastereoselective

Nln-an

_

I

d r"Tlr r:rt:fc 9

chloride' N-Benzoyl-4-(dimethylamino)pyridiniumi,otat"d 1n947oyield andusedfor the direct been has o.Benzoates,| d;;;;;;. of alcohols' benzoYlation lwolf". M. S.SCn, 29'l5 (199"1).

HzN I

'l

l-r:-iltr\

MeOH

. N\n

BH+ (1)

b,r (1997)' rHuiipoo., A. R' T53'16883

azocompounds' |.Benzy|.4-aza.1-azoniabicyc|o|2.2.2loctaneperiodate. glu" ttbonyt productsand oxidation.' Alt"h;i;;;'arylamines in MeCN' resPectivelY,

.-

Berylliumchloride

23

I the

Carbonyl compounds are recovered from imines2 and Cleavage ofthe C=N bond. oximes3on reaction with the reagent.Note that the correspondingperoxodisulfate salC has

\\ lth

the same capability. 'Halipour,A. R., Mahboobkhah, N. IJC 37B.,235(1998). 2Huiipou.,A. R., Mahboobkhah, N. SC28, 3143(1998). 'Ha;ipour,A. R., Mahboobkhah, N. JCR(S)122(1998). -Hajipour,A. R., Mohammadpoor-Baltork, I., Kianfar,G. BCSJ71,2655(1998).

lnto (rh()ls

Benzyl N-(benzotriazol- l-ylmethyl)carbamate. Aminomethylntion.l This reagent serves as an electrophile for Evans N-acyloxazolidinones. The Cbz group can withstand conditions for removal ofthe chiral auxiliary (e.g., LiOH, FlOr) but is cleavableby hydrogenolysis. rArvanitis,8., Ernst,H., Ludwig,A. A., Robinson, A. J.,Wyatt,P.B. JCS(Pl)521(1998).

e(h]ne

O -Benzyl S-propargyl dithiocarbonate. BenzSl esters.t The reagent,formed by treatment of benzyl alcohol with NaH, CS, and propargyl bromide in THF at room temperature,esterifiescarboxylic acids in refluxing toluene(9 examples,74-98Vo). I

M., Zard,S. Z. TL 39,7301 ( I 998). Faure-Tromeur,

I Jlrect

Benzyltriethylammonium tetrathiomolybdate. r*Azido carbonyl compounds undergo reductive cyclization (6 Cyclic imines.I examples,67-90%).

cntl\ ln

=?o ('.-(*'

o q "'

gHo

lBnNEt3l2MoSa

rY-JA =}-..)

o

Ph

870/"

Prabhu, K. R.,Sivanand, P.S.,Chandrasekaran, S. SL47(1998).

n[\)unds,

Beryllium chloride. 19,23 Organometallicreactions.t In promotingreactionsof Grignardand organolithium with 2-cyclohexenone, is solventdependent. reagents chemoselectivity

fr $

rll

1,1'-Bi-2,2'-naphthol-gallium-lithium complexes

(/-\t s o \_J

I I BuLi +

BeCl2

Bu-BeCl

Bu

( E o

rnr

-j

7'1"/o

I

/-\

I

w

.-v. : /':-
Js\,/'V

Pauson-Khandreaction, The intramolecular reaction of 1,6-enynes3is catalyzed by [ClRh(CO)r1, in dibutyl ether under CO. rwender, P. A., Rieck,H., Fuji, M. "/ACS120,10976(1998). 'Wender, P. A., Sperandio,D.JOC 63,4164(1998). rKoga,Y., Kobayashi, T., Narasaka, K. CL24g (1998).

Bis(dicarbonylcyclopentadienyliron). Allylanilines.t Alkenes react with severalnitroarenesto give allylanilines. However, p-anisidine is not a suitable aminating agent.

CO / [CpFe(CO)2]2 +

PhNO2

+

1 6 0- 1 8 o o

GI \1,,\z

NHPh

64"/"

'Srivastava, R. S., Nicholas,K. M. CC 2705 (1998).

I, l -Bis(dimethylamino)-2,212-trifl uoroethane. Condensation wilh ketones.t The aminals serve as synthetic equivalent of rifluoroacetaldehyde. Thus, its condensation with ketones (catalyzed by aqueous HCI) gives 2-(l-hydroxy-2,2,2-tifluoroethyl) ketones and reaction with silyl enol ethers rcatalyzedby ZnClr) delivers the trifluoroethylidene ketones. r't\-r < ,:()l1998)

+ n. f-..lJr versions2of the h... : neen develoPed.The u..: ..:.rlcdseven-membered

cF3cH(NMej2

znctz Et2O

,

Fsc

cFs

(R)'2,2"8is(diphenytarsino)-1'l'-binaphthvl

40

g-Bicdi?

8cr|dltlr coodcasr

lxo. Y., Dolbier,w. R. 7L 39' 9151(1998)'

1,2-Bis(dimethYlsilYl)benzene' acids via the Cyclization of co-hydroxycarboxylic Mesocyclic lactones'l 8- to to medium-siz"d.tinCt-17-l-::be.ted'.35Vo" O,O'-disilyl intermediates is aiplicable by catalyzed is silyl carboxylate formation step l3_membered, 1g-ggvo). An^initial at O-silylation is tt]"-*^"U by an intramolecular (Ph3P)lRhCl at room Emperature which cyclic the occurs when g0". Elimination or r,r,:;-tetramethylbenzo-2,r,3-oxadisilazore silylether/estersare exposed to MerSi(OTf)t'

Hara:.cT. ! Coppa, Albl4t rcadilr obte

Pntd

I rz

o

Ao* t \o,

R rz

HSi)i\

^t'(v

f*o'''lO \o'.

(Ph3P)3Bhcl

(Ph3P)3Rhcl 250

8oo

rr'(v

a\o't'1fr

{"'i'io I

Eec ta ft ttlarnGd

Mersi(orf),

a95'/. (>95.5% ee)

n

lc:rnc silYl acetals

rBtandin, V., Carpentier, J.-F.,Mortreux,A. TA9,2'765(1998\rDoi,T., Kokubo,M., Yamamoto, T. JoC 63,428( 1998). K., Takahashi, rRatovelomanana-Vidal, V., Genet,J.-P.JOMC567,163(1998). rHenry,J.-C.,Lavergne, I P , Dolgina'T' M ' V., Genet,J.-P.,Beletskaya, D., Ratovelomanana-Vidal, (1998). TL39.34'13 sohku-u,T., Ikehira,H., Ikariya,T., Noyori,R. SL467(1997). 6Doucet, E', England,A F ' T., Kozawa'M., Katayama, H., Ohkuma,T., Murata,K., Yokozawa, (1997). 1'703 R. ACIEE 37, T., Noyori, _lkariya, Fan,Q.,Yeung,C.,Chan,A. S. C. 7A 8,4041(1997). Silver complexes The 1-selective reactions of crotylstannanesr and 5-trimethylstannylAllylation, 1.3-pentadiene2 with aldehydes are highly enantioselective when promoted by a BINAP-AgOTf complex.

Bismuth(III) bromide

Agorf / (R)-BINAP

,l*o

* /\/"'/"n'""

Actir a Ethers." with Et,SiH in the p compoundsoccun. Substintion ot gI1

OH I phly\

-2OO

THF

\

and glycosyl bromides bases,respectivelr'.ll

61% (90%ee)

Cyclic carbonout with DMF in the presc

Al'dolreaction.3TinenolatesServeasnucleophilesinthecondensationwith aldehydes. lYanagisawa,A., Ishiba,A, Nakashima'H ' Yamamoto' H' Sf 88 (1997)' H' SI, 933 (1997)' tV^""gi**", A, Nakatsuka,Y, Nakashima'H'' Yamamoto' (1997)' rYanagisawa,A., Matsumoto,Y', Nakashima'H ' Asakawa'K" Yamamoto'H JACSII9'9319

1,2-Bis(diphenylphosphino)ethane' superior is ligand The Mitsunobu and Staudinger reactions't oxide by-product is easily removed' triphenylphosphine becausethe phosphine

to

(1998)' 'o'N"il, I. A., Thompson, S , Murray'C' L'' Kalindjian'S B TL 39' 7787

Bis(fl uorosulfonYl)imide' and benzylic alcohols with Deoxygenative allylation of allylic Allyhtion.' (FSOt)'NH' allyltrimethylsilaneis promotedby

Ph

,nMo"

+

SiMe3

,(< Sulfoxides.6 n catalyst.

lKomatsu, N., Uda.\t . ! lKomatsu, N., IshidaJ . iMontero,J.-L..\,\'rnu

(t99'7). twinurn, J.-Y.,Kamal.I il-e Boisselier, V.. Pcxtc 6Komatsu, N., Uda.\t . !

(FSO2)2NH

c{2cl2

,^^/.^

-7go

rKaur. S fL 38'2521(1997)' M.,Trehan, C.,Kaushik,

Bismuth. with allylic of sulfonylchlorides cross-coupling Thedehalogenative iiii ,rWnrr.' canbe usedinsteadof bismuth' halidesby Bi is a usefulreaction'Cadmium rBaruah,M., Boruah, A., Prajapati,D ' Sandhu'J' S' SL 1083(1998)'

Bismuth(Ill) bromide. Cyanohydrinsandhomoallylicacetals,|ReactionofMe.siCNwithaldehydesand is BiBr, at room temperature'whereasSbCl.t allylsilaneswith acetalsare catalyzedby completelYineffective'

Bismuth(Ill) chlorid Michael reaction in the presenceof I examples,80*90% t. Carbonyl regeaa cleavedin a BiCl.-c: 'l Episulfides.s

ammonium thioclar 96-99Vo). Dicls-AWer req.

furnish dihydropyan Diels-Alder reactions

Allylations. H( compoundswith alllli rZn for keto acids.' r employing Mg-BiCl,

Bismuth(III) chloride

\

Ethers.' Activated carbonyl compounds undergo reductive coupling on treatment with Et,SiH in the presence of BiBr3. With silyl ethers heterocoupling of carbonyl compounds occurs. Substintion at glycosyl site, Glycosyl esters are converted to glycosyl bromidesl and glycosyl bromidesto nucleosidesa by reactionwith Me.SiBr and silylatednucleoside bases,respectively,when promotedby BiBr..

.icnsation with

Cyclic carbonates.s Epoxides are transformed into cyclic carbonatesby reaction with DMF in the presenceof BiBr. and oxygen.

n ./Y

I r e .e 3 l 9( 1 9 9 7 ) phA

n Y ll

. H

BiBr3 / 02 NMe,

11 0 0

o-40 Ph/\-o 567.

Sulfoxides."

The air oxidation of sulfides can use BiBr.,-Bi(NO.)., as a binary

catalyst.

!\

!: -

.rlcohols with

tn

rKomatsu, N., Uda, M., Suzuki,H., Takahashi,T., Domae,T., Wada,M. IL 38, 7215 (lggl). 2Komatsu, N., Ishida,J., Suzuki,H. TL38,72lg (lgg7). rMontero, J . - L . , W i n u m , J . - Y . , L e y d e t , A . , K a m a l , M . , P a v i a ,A . A . , R o q u e ,J . - P . C R 2 g 7 , l ' / 5 ( 1997\. oWinu., J.-Y., Kamal, M., Barragan,V., Leydet, A., Montero, J.-L. SC 28, 603 ( 1998). 5Le Boisselier,V., Postel,M., Dunach,E. CC 95 (l9g':-). 6Komatsu, N., Uda, M., Suzuki, H. CL l22g (lggi).

.\,\ Bismuth(Il! chloride. 15, 37; 18, 52;19,37 Michael reactions.t Reactionof 1,3-dicarbonylcompoundswith Michael acceptors in the presenceof BiCl. by irradiation with microwave proceedswithout solvent (6

':'ideswith allYlic

.. n-

-

.-::,1.

lh aldehYdesand r hereasSbCl, is

examples,80-907o). Carbonyl regeneration. Oximes,2 semicarbazones,3and dimethylhydrazonesaare cleaved in a BiCl,-catalyzed reaction,also undermicrowaveirradiation. Episuljides.s The transformation of epoxides into episulfides by means of

('r

ammonium thiocyanate in refluxing MeCN is promoted by BiCl. examples, 96-99Vo). Diels-Alder reactions. Activated carbonyl compounds condense with dienes to furnish dihydropyrans6at room temperaturewhen catalyzed by BiC\. Conventional Diels-Alder reactions catalyzedby BiCl. or Bi(OTf)., have also been scrutinized.T Allylations. Homoallylic alcohols are formed by the reaction of carbonyl compoundswith allylic bromides when the latter are treatedwith BiCl. and a reducing agent tZn for keto acids,8 and NaBHo for aldehydese).Alternatively, a Barbier-type reaction employingMg-BiCl, is more convenient.r0

46

Bismuth(Ill)nitrate

cooH

/\,"' ## ^X::"78o/"

from generated Enolates Reformatsky-type reactions and reductions. various with condense medium an aqueous in s-bromoketonesby reactionwith BiClr-Al aldehydes to give B-hydroxy ketones.lr A modification of reaction conditions (BiC1.-NaBHo) and in the absence of aldehydes leads to hydrodehalogenation of the haloketones.l2 Nitroarenesare reducedto N-arylhydroxylamineswith BiCl,-KBH.'r3 A bismuth complex derived from BiCl. and diethyl tartrate mediates Cyanohydrins. asymmetricaddition of Me,SiCN to aldehydes(6 examples,20-727a ee)'ta rBaruah,B., Boruah,A., Prajapati, D., Sandhu,J. S. ?I 38' 1449(199'l)' 2Boruah, J. S' fL 38' 4267(199'7)' D., Sandhu, B., Prajapati, A., Baruah, 38aruah, (1998). 28,4157 S. SC J. D., Sandhu, B., Prajapati, aBoruah, J. S. SL 1251(1997)' D., Sandhu, B., Prajapati, A., Baruah, sMohammadpoor-Baltork, 1.,Aliyan,H. SC28,3943(1998) 6laurent-Robert, B., Dubac,J. TL39,l l6l (1998)' H., Garrigues, Tcarrigues, F.,Robert,H.' Dubac,J. JOC 62,4880(1997)' B., Gonzaga, twudu,M., Honna,M., Kuramoto, 2265(1997)' Y., Miyoshi,N. BCS"I70, eRen,P.-D.,Shao,D., Dong,T.-W.,Jin,Q.-H.,Yao,Z.'P' SC27'2569(199'7)' l0wudu,M., Fukuma, T., Miyoshi,N IL 38' 8045(1997)' T., Morioka,M., Takahashi, I rShen,2., Zhang,J.,Zou,H., Yang,M. TL 38' 2'133(1991)' r2Ren, (199'7)' P.-D.,Shao,D., Dong,T.-W.,Jin,Q.-H.,Yao,Z'-P'SC27'25'7'7 I3Ren.P.-D.,Pan,X.-W.,Jin, Q.-H.,Y ao,Z.-P-SC27' 349'7(1991)' raryodu, T., Miyoshi,N', Smith,K' fA 8, 3939(199'7)' T., Domae,T., Fukuma, M., Takahashi,

\l5t

Bir

q r-rdx rllcr

I n?hr

Ft r r 11

l-.Ert

inx :bc . i{lr

Bismuth(Ill) mandelate. Ester hydrolysis.t With 570of the Bi(III) salt in DMSO selectivehydrolysis of esters is is achieved.Thus, p-cresyl acetateis recoveredquantitatively while p-nitrophenyl acetate convertedto the Phenol. Cleavage ofepoxides and s,hydroxy ketones.2 oxidativecleavageof CC bondsby air'

The bismuth salt is a catalyst for

rLeBoisselier, E. TL38'2981(1997). M., Dunach, V., Postel, 2Kullul.K.. Coin,C.,Dunach, 8., Postel,M. NJC 21,495(199'7).

frlr {l &:Er leljc

bp

o, Bismuth(IlD nitrate. on Pyridines.t Hantzsch 1,4-dihydropyridines undergo dehydrogenation (7 examPles, exposure to bismuth nitrate pentahydratein HOAc at room temperature 5O-9OVo).

rthr

E 5f .!t rrrrqlr

47 Bis(pentafluorophenyl)borinicacid ETOOC-.,.z1,,.COOEt

ETOOC-.,r,--..,r,COOEt

,

il tl

r.rn

Bi(No3)3.5H2o, 2oo

HoAc

H

lrom

ll 'A*A

I 75"/"

rMashraqui,S. H., Kamik, M. A. S 713 (1998).

I \ Jnous ! nJ i t i O n s )n ,,t the

Bismuth0ll) triflate. *Hydroxy y-lactones.t Thereagentwhichis stableto watershowsexcellentLewis and acidicproperties,includingthe ability to effectenereactionsbetweenglyoxylic acids alkenes.

n',4(llates

-\

l Y' I

Fr,

+

o

i[ '/\' H' cooH

Bi(orf)3 +

*#"*,.

e{

] *

x-o

R R '

: I rf

to Mukaiyama aldol reactions.2 The catalytic activity of this triflate is superior lanthanidetriflates.It can be recoveredafter reaction' acid Friedel-Crafts acylation.s The triflate has many advantagesover other Lewis

!

catalystsfor acylation(1 1 examples,75-96Vo). rLaurent-Robert, H., Le Roux,C.,Dubac'J' S, 1138(1998)' tL" Rou^,C.,Ciliberti,L., LaurenrRobert, A'' Dubac,J' SL 1249(1998)' H', Laporterie' tD"r.u.r. J. R., Labrouillere, A'' Dubac'J' ZL 38' 8871 H'' Laporterie' M., Le Roux,C, Caspard' ( I 998). . \)l estefs .raetateis

.rialvst for

Bis(p -nitrophenyl) phosphorazidate. Alcohols including sugarsare convertedto azidesdirectly on treatmentwith Azides.t the reagentand DBU. 'Miruno,M., Shioiri,T. CC2165(199'7).

lcn.rti(.)n on | .\amples,

Bis(pentafl uorophenyl)borinic acid. Benzylic and allylic alcohols undergo oxidation to Oppenauer oxidation.t aldehydesby a combination of (cuFr)rBoH and t-BucHo at room temperature. reaction Enones.2 The hydroxy ketones obtained from Mukaiyama aldol by the dehydration catalyzed by bis(3,4,5-trifluorophenyl)borinic acid undergo stronser borinic acid.

i

Il

l|8

Bis(pentamethylcyctopentadienyl)dimethyluranocene

QSiMes PhCHO |. + r"vnv +

pnA

Bis (pentamethylcycloPcot Tcr hAlkyl acetates.' isopropenyl acetate in th

cH2cl2 ' 78o F r

acetate. Primary and sec< acetatewhen sufficient anx

[rt]fro" t ' Y t z

medium.

f

rTashiro.D.. Kawasaki,Y.. Sd

H' JoC a' 5664(199'l)' llrhiharu,K., Kurihara, H.' Yamamoto' H' sL597(199't)' 'iffi;;, r., ro.ittu.u,H'' Yamamoto' Bis(pentafluorophenyl)tindibromide' Atdol-typereactians.IThereactionofketenesilyletherswithcarbonylcompounds prefersketoneto aldehydes' underthe influenceof this tin bromide

. ,,A

Reaction with alhyna. simultaneously inftoducing sulfi des undergo cyclizatio

t-BuMe2SiO (coFs)zSnBrz

osiMe2t-Bu or

Bis(pyridine)iodin(I) tcttt Good 1t Iodinations. parent enaminotE from the peptides2with this reagentr

cHO

cH2cr2-78o

l*-\--l-\-cHo

,//

-Ph Py2l8Fit

l-,-_Z

(1998)' lchen,J.,Sakamoto, K., Orita,A'' Otera'J' JOC 63'9739

l

II Ph,^l

Bis(pentamethylcyclopentadienyl)dimethyluranocene' in refluxing benzene to ih" hydrou*ination of 1-alkynes Imines from I_altqnes.t is contrary to the which (Cp*)'UMe' as catalyst' give aldimines is regioselective using of the thorium presence the in (much lower yields) formation of methyl ketone ketimines analog(Cp*)rThMer.Exceptionarnongthelatter"u'"ti'trimethysilylethynewhichgives N-methyl-2-trimethylsilylacetaldimine'

Cp'2UMe2

R-

FNR'

r

-

CHf

-eop 10

93"k

'Campos, P. J., Arranz, J.. Rod lBarluenga, J., Garcia-Manin rBarluenga, J., Llorente. 1.. .r Garcia-Granda,S. JACS llt. rBarluenga, J., Romanelli.G P S., Garcia-Granda,S. AClff

s0 - 95%

R---

+

*ts'*'

R'NH2

THF

7 -80"h

lHaskel,A., Straub,T., Eisen,M' S' OM 15'37'13(1996)'

3J-Bis(tributylstannyl)p Homoallylic MOM crt carbonunitsis accomplist andBuLi (2 equiv HMPA beforeworkup).Chainelm lf stepwiseadditionof ICI i productsarethe l,3diol m

33-Bis(tributylstannyl)propyl methoxymethyl ether

,.\

/ P h

Bis(pentamethylcyclopentadienyl)samarium. t-Alkyl acetates.l Tertiary alcohols are acetylated under acid-free conditions with isopropenyl acetate in the presence of (Cp*)rSm(thf), and cyclohexanone oxrme acetate. Primary and secondary alcohols undergo acetylation without isopropenyl acetatewhen sufficient amount of cyclohexanoneoxime acetateis addedto the reaction medium. lTashiro,D., Kawasaki, S.,Ishii,Y. JOC 62,8141(1997). Y., Sakaguchi,

l\,n1P()unds

Bis(pyridine)iodine(I) tetrafluoroborate. Good yields of 2-iodoenaminones(7 examples,9l-95vo)t are obtained Iodinatinns. from the parent enaminones.Iodination of aromatic residues (such as that of tyrosine) of peptides2with this reagentis facile. while give dimers Reaction with alkynes. (r-Butyldimethylsilyl)alkynes alkynyl products.r Certain the simultaneously introducing one or two iodine atoms into sulfides undergocyclization.a

-cHo

,i

,,,.2'n ll Ph, F \'nrene to n:r.rr\ tO the i :i'.cthorium '..hrchgives

I

Py2lBFa/ HBFa

$iMe2But / HBF4 PyrlBF4 I

CH2CI2

lll

- goo , -250

Jn

1 0h

*,"b

*

ButMe2Si\.,'.1 ll

tn'"\

-eoo- -goo 20 h

-\Ph

95"k

93"/" I i !

'Campos, P. J., Ananz, J., Rodriguez, M. A. 7L 38, 8397 (1997). lBarluenga, J., Garcia-Martin,M. A., Gonzalez,J. M', Clapes,P', Valencia,G. CC 1505 (1996)' rBarluenga, J., Llorente, I., Alvarez-Garcia, L. J., Gonzalez, J. M., Campos, P' J'' Diaz' M' R'' Garcia-Granda,S. JACS 119,6933 (f99?). rBarluenga, J., Romanelli,G. P., Alvarez-Garcia,L. J., Llorente,I., Gonzalez,J. M., Garcia-Rodriguez, S., Garcia-Granda,S. ACI EE 37, 3 136 (1998).

i

i

11 lll

ll w n

!it { l

iili methoxymethyl ether. 3J-Bis(tributylstannyl)propyl Homoallylic MoM ethers.t chain elongation of aldehydes and ketones by three carbon units is accomplishedby exposureto the lithiated speciesgeneratedfrom the reagent and BuLi (2 equiv HMPA). Reaction with esters affords ketones (which can be alkylated before workup). Chain elongation of alkyl halides by three carbonsis readily accomplished. If stepwiseaddition of ICI and HrO, preceding termination of the reaction is carried out the products are the 1,3-diol monoethers.

ii

,

50

N,N-Bis(trimethylsilyl)benzenesulfenamide

-#h "u..n{Xo"o" i,.,^^"n,""

PhCOOMe

Rx;lcl; I HooH I OH

are susceptibleto a

f _"YA .

| L

o"o"

after proper workul

oli I r,n"t

I

I

tn/tAo"ot

t{o (,

Wo

phs '-

*L*o" llsono.N..Mori.M. JOC63,fi'B (1998). Bis(tributyltin)oxide.13,41-42;15,39; 18' 54;19'40 Aminesfrom azides.t The oxide reagentis convertedin situ into BgSnH by a hydrosilanesuchasPhSiI{3to effectthereduction' rHays, (1998). D. S.,Fu,G.C.JOC63,2796 oxime O-mesylate. 4,4'-Bis(trifluoromethyt)benzophenone Grignard reactionwith the reagentgives Primary amines.t Copper(I)-catalyzed N-substituted imines. Acid hydrolysis releases the primary amines and the bis(trifluoromethyl)benzophenone. rT.utrr.i, H., Hayashi, Y., Narasaka, K. CL 317 (1997).

Bis(triflyl)imide. Michaelreactions.t Transferof an allyl groupfrom allylsilanesto the p-positionof proceedsin thepresence of TfrNH. cycloalkenones rKuhnert, N., Peverley,J., Robertson,I.TL39,3215 (1998).

N,O-Bis(trimethylsilyl)acetamide. Enamination.t Ketone condensationwith secondaryamines using BSA [or is also Iodomethane as dehydratingagentis quite advantageous. bis(trimethylsilyl)ureal present. rYamamoto, Y., Matsui,C.JOC63,377(1998). N,N-Bis(trimethylsilyl)benzenesulfenamide. aldolreactionareconverted Cyclizntion.t Diketonesthatcanundergointramolecular The products and PhSN(SiMer)r. BuoNF by treatmentwith sulfenimines to cycloalkenone

.Barbot, F., Aiderr. V

Bis(trimethylsigl I Baeyer-Villiga rn thepresence of a Gonlich, R., Yanulor

Bis(triphenylphoc ftKeto sulfonet catalyzed by (Ph.Pr rKamigata, N.. Udodr

Bis(triphenylphoed Conjugated e* reaction of carbonr I end (EIO).,P.

Ledford.B. E.. Carrcr

Bis{triphenylstenny

Dehalogenatiot Jehalogenationof r r'complished. Th€ rE :.\ $ aler.

:.hulrz.E. K. \' . Harp

Bis(triphenylstannyl)selenide 5l

tc\,oM

are susceptibleto attack by Grignard reagentsto afford [ -substituted 2-cycloalkenamines. after proper workup.

-vo-?o ""*o"

PhsN(siMe3)2 |

--l-Y*ttn

( r ; B A F ; r F * l V l

/\'/MsBl

l HCI: NaOH

rBarbot, F., Aidene,M., Miginiac, L. SC 28, 32'79(1998).

lu SnH bY a

Bis(trimethylsilyl)peroxide. Baeyer-Viltigeroxidalion.t A newprocedureusesthe silyl peroxideastheoxidant of a Lewisacid(e.g.,SnClo)' in thepresence 'Gottlich. R.. Yamakoshi,K., Sasai,H., Shibasaki,M. SL 971 (1997).

rr.rrent gives r\ and the

dichloride. Bis(triphenylphosphine)ruthenium of silyl enol etherswith a sulfonylchlorideis Sulfonylation ftKeto sulfunes.t ( 50-9 17o). (Ph,P)rRuCl, s, I 8 example catalyzedby rKamigata,N., Udodaira,K., Shimizu,T. JCS(Pl) 783 (1997).

e J-positionof

Bis(triphenylphosphine)trichlorooxorhenium' Conjugated esters.t An alternative to the Emmons-Wadsworth reaction is by reactionof carbonyl compoundswith a diazoaceticesterin the presenceof (Ph.,P)rReOCl., and (EtO).,P. rLedford, E.M. TL 38,8125(1997). B.8., Carreira,

srng BSA [or nerhaneis also

Bis(triphenylstannyl) selenide. In the presence of fluoride ion the effective Dehalogenation of *haloketones.t (PhrSn)rSe in MeCN at room temperature ls by of cr-haloketones dehalogenation significantodor and is not sensitive it has no handle as is easy to reagent The accomplished. lo water.

on .rreconverted r. The Products

E. K. V., Harpp,D. N. S I 137(1998). Schultz,

Borane

52

-Enlcrr.

9-Borabicyclo[3.3.1]nonane . 14' 52-53; 15' 43-44; 17' 49-50 on the other hand, the Reduction of turtiary amides.t Tertiary amines are produced. aldehydes' reduction with dicyclohexylborane or disiamylborane affords Through chelation with 9-BBN the selectivealkylation of 2-aminobenzllnmine.2 group (t-BuoK, RCH2X)' benzyl amine is quantitatively alkylated at the side chain amino LiberationofthealkylatedproductsisbyhydrolyriswithaqueousHClorNaoH. delivers a primary cleavage of 2,2-dimethyl-4-pentenoic esters.3 Hydroboration on treatment with function alcoho'l which undergoes intramolecular attack on the ester of alcohols' protection for NaOH. This procedure enablesthe use of such hindered esters ester' tertiary a group from The development arosefrom failure of removing the pivaloyl

lJrr \a&L

Borr Bo.z enJ ca 3nfraDcl \]ratrt

rgent

nr :ai.r-D(

o

.o \\ /:\

UX

'-(

oH

/\-

)

EtaN/cH2ct2

O''T

Br.ra. tB"-r irdrfil '1^rrd| '\nrr

99%

9 - B B N /T H F ; N a O O H

trla

rcodjoiun,G., Singaram' B. IL 38' 1717(199"7)' 2Bar-Haim, G., Kol, M. rL39,2643 (1998)' 3Crimmins, M. T., Canoll,C. A., Wells,A. J. TL39,7005(1998)'

r3lrE:1

:{r*crrc R6d ;.rcrJ to

Borane. 18, 58; 19, 42-43 Hindered tertiary amines such 2,6-disubstituted Reduction of hindered imides.t imides with borane' arylamines can be preparedby reduction of the corresponding of chiral aminesfrom preparation the enables cleavage of hydrazines.2 This method SAMP and RAMP hydrazonesin two steps' of 1,2-diphenylcyclobutene cis_2,5-Diphenyhorolane.3 An unexpected reaction which on conventional boracycle, ofthe with borane results in the stereoselectiveformation

EAm

Io r6rran

>

rt

oxidation gives the meso-diol.

Ph

-----rPh

lll

BH.'1116

---:* 50"

PN

Ac tiv ation of aziridine s.complexation with borane.

A I B

x

H

OH

,n&'n

0n

Ph

90%

Lithiation of aziridines with s-Buli becomesroutine after

rAkulu,M. R.,Kabalka, c. w. sc 28,2063(1998).

IJ '-"ioa

Borane-dimethylsulfrde

)

'- : ,rtherhand.the

ku .\rrh g-BBN the C

BuOK.RCHrX)' \rOH.

o{:

.:rers a pnmary ,:t treatmentwith

r

) r : i .lron of alcohols. fr :: . .t tertlary ester.

53

2Enderr, D., Lochtrnan, R., Meiers, M., Muller, S., Lazny, R. S/- 1182 (1998). 3lh".-itt", F., Knochel, P. ACIEE 37,2460 (lgg8). aved"3r, E., Kendall,J.T. JACS ff9,6941 (1993).

Borane-amines. 13, 42; 18, 58; 19, 43-44 Borane adducts with N N-dialkylanilines are desirable reagentsbecausethey are liquids and easy to handle.l The N-ethyl-N-isopropylaniline is a superior reagent which shows enhanced reactivity in dioxane but low reactivity in dichloromethane.2 The borane-N-trimethylsilylmorpholine complex is a crystalline and air-stable hydroborating agent.3 Reductions.a anti-1,3-Diols are produced from B-hydroxy ketones when the reduction is carried out in the presenceof LiClOo. iBrown,H. C.,Zaidlewicz,M., Dalvi,P.V. OM 17,4202(1998). rBro*n, H. C.,Kanth,J. V. 8., Zaidlewicz,M.JOC 63,5154(1998). rsoderquisr, R. ZL 39,6119(1998). J. A., Medina,J. R.,Huertas, osalunkhe, A. M., Burkhardt,E. R. Zl38, 1519(1997). sNu.ayana, C., Reddy,M. R., Hair, M., Kabalka,G. W. fZ 38, 7705(1997).

/,-

Borane-dimethyl sulfide. 14, 53; 15, 44; 17, 50-51; 18, 59; 19, 44 Reductions.t Derivatives of amino alcohols are obtained from the corresponding ketones in which the amino group is protected as phosphinamide. Diastereoselectivity is observedwhen the protected amine is situated in close proximity to the carbonyl group.

E\ Dr

1.6-disubstituted :h borane. , hiral aminesfrom ::phenylcYclobutene r.-h on conventional

Reductive amination of ketone* is accomplished in two steps.The borane complex is used to reduce RRGNF{,+C1- which are formed by condensation of the ketones with ammoniain the presenceof TiCl-Ti(OPr")0. A convenient preparation of N-methylanilines is by Methyhtionof anilines.' sequentialreaction with HCHO, borane-dimethyl sulfide, and iodine/aqueousNaOH.

Ph.r,,..:rU- Ph

t- N -

l

BXe BH3'5Y", +

OH

![.: 'teomes routine after

.+

I NaOH, 12 Ph-N-Me l--------*

PhNHMe

THF

I Ph

^Ytn

[Ph-N=QF{2

95"/o

Unsaturated chromium Fischer carbene complexes are converted l,3-Diols.a I,3-diols under standardhydroboration conditions using borane-dimethyl sulfide.

OMe T'"-

BH3.SMe2/ THF;

pnN\4coru ffi

oH I

pnMon*rnMo" 1Q%

54

Borontrichloride

T' C'' Wills',M'.T54' 8827(1998)' rPulme., J' R', Walsgrove' M. J', Studley, ACS51' 351(1997)' T 'lJunrron, A., Lindstedt, Olsson' E'-L', 3Hu,H.-J.,Ahn,Y.-G.sc 27,1543(1997)' F' I ' TL 38' &65 (1997) aBarluenga, F'' vud""u'd' J'' Fananas' "', ^*n;;;'' J.,Granados,

Diisopinocamphcybhb preparationof IpcrBCl in sin 81.7-l00%o yield, 87-99% c Silic onlb oron exc haagt

alkenylsilane is convened rc a oroduct can be used in Suz

19' 45 Boron tribromide.13, 43;14,53-54;18'59; useful and highly reactivedienophilesare These Cycloalkenyldibron,o,boranes'1 with BB5' The Diels-Alder adductsare preparedfrom cycloalkenyltributylstannanes readilyconvertedto angularbicyclic alcohols'

BO

MessirV),:r7t:rsirvre3

"*,

/ / \ :

.***^J"

BB13

HOOH 80%

glycals are formed as major products from 2-Deoxy'a,glycosides'2 The glycosides is used as promoter' by addition of alcohols' BBr, or BCl, ll-ee,Y.-K., Singleton,D' A' JOC 62'2255(199'7)' S' SL 1007(1998)' 4ori,irnu, K., Nagai,H., Ushiki' Y ' Matsumura'

rButler,D. C. D., Alper,H. CC 2lh".mitte, F., Knochel,P. ACt 3crane,S.N., Bumell,D.I. tol azhao,M., King, A. O., Lffs.r. sBubud.i,F., Farinola,G. M.. F

Boron trifl uoride ethenla 6O-63;19,46-48 Oxidative decompositb treatment of nitrite esterssi

59-60;t9'45-46 trichloride. 13' 43;14,54;15' 44; 18' Boron *'";;;;r"""rr;., unit on trearmentwith BcL and Et,N alcohol an lose esters carbamate ..r h^, ^-f, an organtc inrefluxingbenzene. BClt and A sequential reaction of RBt! with Aminesfrom boranes' equation of configuration. The following azide leads to the amine with retention

Acao Glycosylation. It has bccn other alcohols.2 mediated byesterswhich is is the rean Of interest ethersto 3+etrahydropFanl

illustratesastereoselectiveapproachtocycloalkylaminesonthebasisoforganoborane isomerization.2 t

t BnNH

HzB. Ph

(.*rn i l

BH3'THF

"'Ph

5oo

""Ph

B C t g; BnN3

l

cun.,fo/',"o^'

\...Ph

(

l V,",cn 81"/"

An improved method for the synthesis 4,4-Dimethyl'7,3-cyclopentaned'iones'3 with involves a BCI ,.-catalyzedieaction of 3,3-dimethyl-1,2-bistrimethylsiloxycyclobutene ketones.

l

Thc Aldol reactions. r-butylthioetheneas dons c .ilyl group has a crucial cfft :re formed by treatmentof a an acetal side chain.6

Borontrifluorideetherate 55 Diisopinocampheylchloroborane.a A convenient and economical method for the preparationof IpcrBCl in situ (for asymmetric reduction of alkyl aryl ketones, l0 examples, 81.7-I00Vo yield,87-99Vo ee) is by admixture of BCl, with NaBH, and cr-pinenein DME. Siliconlboron exchange.s For the sake of increasing reactivity in coupling an alkenylsilane is converted to a boronate by reaction with BCl, and then with catechol.Such a product can be used in Suzuki coupling. nophilesare dr': .rriductsare

Bcr3 O-" Messi..v)^:..v4sir,,,,r. ao-4.,A6r,"". ffi

Phl- Pd(o) PhVVsiu",

Y-'-I

r

rButler,D. C. D., Alper,H. CC 25'75(1998). 2lh".mine. F., Knochel,P. ACIEE37,2460 ( 1998). 3crane, (199S). S.N.,Bumell,D.J. JOC63,5708 azhao,M.,King,A. O., Larsen,R. D., Verhoeven, T. R., Reider,P. J' TL38,2641(199'7)' 5Bubrd.i,F.,Farinola, L., Naso'F. T54' 1085(1998)' V., Mazzone, G. M., Fiandanese,

UC\ andEt,N

!. l\

.,nJ an organic '.\lng equatlon : \rrganoborane

Boron trifluoride etherate. 13,43-41',14, 54-56; 15'45-47;16,44-4'7;17' 52-53;18' 60-63; 19. 46-48 Oxidative decomposition of nitrile esters.t Aldehydes and ketones are formed on treatment of nitrite esterswith BF3'OEt2(net elimination of HNO)' Glycosylation, Acetoxymethyl glycosides undergo catalyzedalkoxy exchangewith other alcohols.2It has been shown that BF3'OEt2 enhancesthe displacement of glycosyl esterswhich is mediatedby Yb(OTO.,.1 Of interest is the rearrangement of 3-tributylstannylprop-2-ynyl tetrahydropyranyl ethersto 3-tetrahydropyranylpropynols.a

a)

cun,/to)""o\.nrr.

lF

I

BF3'oEt2

".k?,

-

cur,fo/"'\on 66% (>95o/. de)

the sYnthesis r elobutenewith

The Mukaiyama aldol reaction employing 1-triisopropoxy-lAld.olreactions. r-butylthioetheneas donor displays exceptional Cram-type selectivity, thus the bulk of the silyl group has a crucial effect on the level of 1,2-asymmetricinduction.s Bicyclic lactones areformed by treatmentof a hydroxyalkylalkyne substitutedwith tungstenand also carrying an acetal side chain.6

56

Boron trifluoriile

etherate

Ho--r. )

cP

(ocbw--

ertoe"

-6*

\

*Pp (oc)dwYo)

Y')

air/ Hzo

BF+-u

C'AcYbb pres€nceof is cs Ho@t

U

CH2Cl2

(Meo)zHcJ

81o/o

77"/"

y'"..rs

to 'rmatic aldehydesfragmentin situ arc and derivedfrom ketones Conventionalaldols affordstYrenes'7

PhtcHo

+

eslcl.

catbafiBre

ryY.^ o

BF3'OEt2

,^n/ P r

i

-'

'\1

HO..AA

Fcrez C . Fac ttkttl.L lL I

o

hexane A

urans'8'.'"1?1llSi]"ltl"n#i'll'uJlj:T:t"fr: s-Metattateit2'3'dihvdrof aldehyc on reaction with

dihydrofuran derivatives converted to PYridines'

I

BF3€E.2: Itoclswto' -;il + MecHo t =rt)

(oc)gw--1

I

SuUotu \ICPBA in dr

i'P'''r ' ueonozHzo

\arnarPr-T-l ft f iunet 'Drrrs.A P-| \jrng. K''$ I XrbdfrG 'L. $'-T.l-r "Dcr. E. Lt? 'f.rrx. E FSugerur V :S4r.n ll S-{e{V '\ crofrr 'Frutrrr

OH

S S

ormations'?"":::"ff:1:::tJ*$lTl}::rt:trT: Functionatgroup,ansf

frrr-t o,*"".."*',',,;':ilr::1,il.,ff:q;["]i]]i#l#,:;_*n"n"n",,.ar I-f6ti is *""';-;;;;, carbamates derived CYcloProPanation' derivatrves' cycloProPane

acetals"andcar

Tr-\rSatBr

\.rs. R - O H'/\ BF3€Et2

OBn

BnO

CH2Cl2

+ BnO""99:t1

J

osiMe2But t.BuLi I -

and

Propargylic carbonates ar I -alkynylsilanols undergo dilir with electrophiles at the propc be used in the preparationof S

N1 \ N-

,^-.'-SlVes B n N'{SiMe3 ll

-

t

TMEDA 82"/o

Halogen-lithiurn exchanges. An improved procedure for the preparation of O,2-dianion of allyl alcohol3consistsof consecutivetreatment of 2-bromo-2-propenol with a Grignard reagentand t-Bul-i. Benzyne-tetheredalkyllithiums are readily generated;those bearing three methylene units undergo cyclization to indans.a Generation of an extremely strained polycyclic compound by fragmentationshas been demonstratedby in situ trapping.

deiodinative

'Shindo, M., Saro,Y., Shishido.K. -Barluenga, J., Sanz, R., Granador 'Hegde, S. G., Myles, D. C. SC Z|. -Bailey, W. F., Longstaff, S. C. .ra Tsuji, T., Okuyama, M., Ohkira V 'Iius, M. A., Hu, H. TL 39, 593i r I Ishikura,M., Matsuzaki,y., Agah 'Uehira, S., Takaku, K., Shinokubo. 'Karsch, H. H., Schreiber, K.. Herk

/-Butyllithium

69

!r, .r.tds are subject ! -:.'n lithiation.

lr

I c c N

N P H

i

h

\ /-\

99:1)

carbonates are converted to substituted allenyllithium species,T but

l-alkynylsilanols undergodilithiation (with t-BuLi-HMPA) and the subsequentreaction with electrophiles at the propargylic position.8 The doubly lithiated N-methyl aminals can be used in the preparation of Si-N- and P-N-containing heterocycles.e

Ir -'..., uith t-Bul-i and B : --' .lenved.

( . . --SiMe3

N-

t-BuLi

-78o

.N-

sict4

Me,N1 ,/-Nlvle

"5r-/'\-J""

^-.-giysa

t r a : ,r the PreParation of

rr()mo-2-propenolwith S i:l

:r.rdily generated;those

o:'.:'. '.rnd by

deiodinative

'Shindo, M., Sato,Y., Shishido,K. TL39,4857 (1998). lBarluenga, J., Sanz,R., Granados,A., Fananas,F. J. ,IACS120,4865 (1998). 'Hegde, S. G., Myles, D. C. SC 27,2111 (1997). 'Bailey, W. F., Longstaff, S. C. "/OC 63, 432 (1998). Tsuji, T., Okuyama,M., Ohkita, M., Imai, T., Suzuki,T. CC 2151 (1997). "Tius, M. A., Hu, H. TL39,593'1 (1998). Ishikura, M., Matsuzaki, Y., Agata, I., Katagiri, N. 254, 13929 (1998). 'Uehira, S., Takaku,K., Shinokubo,H., Oshima,K. SL 1096 (1993). 'Karsch, H. H., Schreiber, K., Herker, M. CB 130, 17"17(1997).

l -(/-Butylperoxy)-1,2-benziodoxol'3(1H)-one

t-Butyl methanesulfonyloxycarbamate' for degradation A modified version of the rearrangement Inssen reafiangernenl ofcarboxylicacidsisviareactionofthecorrespondingacidchlorideRCoClwith triflate, 2'6-di-r-butylpyridine' and sob*"qu"nt treatment with zinc FBuocoNHOMs, RNHCOOBn are obtained' benzyl alcohol in MeCN. Benzyl carbamates P'L' JOC 63' 10040(1998)' rStafford, S' S',Barrett'D' G'' Suh'E' M'' Feldman' J. A.' Gonzales'

-G. Imines.2

1-Butyt-3-methylimidazolium salts' As Asymmetric hydrogenatian'r

ionic

liquids

at

room

temperature

the

imidazoliumsaltsarearecyclablealternativetodipolaraproticsolvents.The tetrafluoroboratesaltServesasamediumintheasymmetrichydro genationof as effectively as the conventional 2-arylacrylic acids (Ru-BINAP catalysts) homogeneoushydrogenationconditions' ""^^';;rr*"-i (at c- 1) in [bmim][PFo] ihe atkytation of indole (at N) and 2-naphthol at room temperatureis highly efficient' of arenes in Aluminum chloride-mediarcd acetylation Friedel_crafts oryiaon.t theanalogousionicliquidl-methyl-3-ethylimidazoliumchlorideoccursatroom temPerature' ?A 8' 1'77(1997)' rMonteiro, A.L.,Zinn'F' K , De Souza'R F ' Dupont',J' teJ",vr. 1.,McCormac, K' R' CC 2245-(1998)' P' B', Seddon' K' R CC2297(1998)' teJurnr,C. J.,Earle,M J', Roberts' G'' Seddon'

/-ButYl nitrite. Benzamides.|t.BuoNoisusefulforthegenerationofbenzynefromanthranilic acid.Abenzamideistbrmedondiazotization(andsubsequentdecomposition)inthe presenceof an alkyl or aryl isocyanide'

f-\-*" \--/

anthraniricacid> $ruHcoen \-J tBuoNo

(1998)' rRigby, s. Joc 63,6"142 J.H.,Laurent, 19' 63 l-(l-Butylperoxy)'1,2-benziodoxol-3(lH)-one' phenolsareconverted p-Substituted 4\hButylperoxy>Z,s-'y-'ion'*adien- 7'ones'| l' and to thedienoneswith a combinationof t-BuOOH

S

reaction with l. substituentto a r-l 'ochiai, M., Natu to.triui, trt.. K.;ltt

Butylstannonic r Transesterifi

secondary alcolm toluene). Functicr

commonly emplo :Furlan,R. L. E.. Y

r-Butylsutfinyl d Aminc pta

r-butylsulfonamrd

These derivativcs they are cleaved I

:Sun. Weinreb! P.,

t-Butylsulfrnyl chloride

-fI

b: Jcgradation I RCOCI with -b,;:r ipYridine,

-Go'.

o-o t-BuOOH

r/Vlr i l t \/--(

b

rt-:,r,1998).

\

/:\

./\

o

(1)

t-BuOO \:,/

/--

Secondaryamines such as 3,4-dihydroisoquinoline are dehydrogenatedon reaction with 1. A similar reaction on N-alkyl-N-methylanilines converts the methyl substituentto a r-butylperoxymethyl group. Imines.z

nncrilture the .."\.-nts' The 1r,,g.'nationof i j,\nventiOnal

'Ochiai,M., Nakanishi,A., Yamada,A. TL 38, 392'l(1997). to"hiui, M., Kajishima, T. H 46,'71(lgg'1). D., Sueda,

t:: hrnimllPFo]

Butylstannonic acid.

i(': ()f arenesln N-,rr\ at room

The transesterificationof carboxylic esters with primary and Transesterification,r secondary alcohols is readily achieved with BuSn(=O)OH as catalyst (e.g., in refluxing toluene). Functional groups such as acetals,double and triple bonds, N-protecting groups commonly employed in peptide synthesis,and B-lactam ring are not affected. rFurlan, A. TL39,2257(1998). R. L. E.,Mata,E. G.,Mascaretti,O.

| ::,'ln anthranilic ns,'ttion) in the

r-Butylsulfi nyl chloride. Amine protection.l Primary and secondary amines are protected as t-butylsulfonamides by reaction with t-BuS(=O)Cl followed by oxidation with MCPBA. These derivatives are stable to strong basesincluding those used for metallation. However, they are cleaved by acid. rSun,P.,Weinreb,S.M. JOC 62,8604(1997).

)P-

Cj'.,'.' iile Convefted

lLee, A . S . - Y . ,y e h , H . - C . ,S h i e ,J . - J .T L t . 'Lee, A. S.-Y., Cheng,C.-L. I53. l.tas5 r t9 -Abele, E., Rubina, K., Abele, R., Gaukhnu

Calcium hypochlorite. 18, 84 Chlorinationof benZami.des.t With large substituents on the nitrogen atom of N,N-dialkylbenzamides the chlorination in aqueous HOAc takes place preferentially at o-lp-positions. Suffoxides.z

A convenient oxidation of sulfides employs Ca(OCl)r-moist alumina in dichloromethane at room temperature(32 examples,60-95Va)' lDong,C.-2.,Julia,M., Tang,L EJOC1689(1998). 2Hiruno, M., Yakabe,S.,Itoh,S.,Clark'J. H., Morimoto,T. s I l6l (1997)'

9

Y

- 7go

i o

l

t

v

A. R., pleynet,D. p. M.. yang. g

1,1'-Carbonyldiimidazole. 13, 66: 16 6 (Jreas.t A mixed urea is formed r

730/"

ftEnamino esters.2 Tertiary imrn ImrCO to give N-(B-aminoacryloyl )imrd Thio estersare obtained when thiols arc i

rBatey, R. A., Santhakumar, V., yoshina-lsh -Fustero, S.,de la Torre,M. G.,Jofre.V.. Car 63,88250998).

l

I -1.-

-\'T-g,

o

Meo.',r.,v\ LDA/ THF

rKatritzky,

then with MeI and another amine. A bar last stage.

3-Carbomethoxypropionylcyanide. y,e-Diketoesterc.t This reagenteffects C-acylationof ketones. It is suitable for of 1,3-cyclohexanedione. C-acylation

a\ t l

Carbonylbis(1,1'-benzotriazole ). (Jreas.r A mixed ureais fornrcd at roomtemperature, thenwith a secon

\

Q.,Sen,S.E. rL39,2249(1998)-

o-Carborane.

Carbonyl protection.t o-Carboran carbinols which are very stableto aqueou carbonyl compounds is effected on trEl temperature.

'Nakamura, H., Aoyagi,K., yamamoto.\.../O Carbon monoxide. Esters. Radical carboxylation without a catalyst is achieved by irradiation of a hexane solution of a secondaryalkyl iodide, an alcohol, and a base under CO (>20 atm).r Primary chlorides and phenylthio groups are not affected. rNagahara, K., Ryu,I., Komatsu,M., Sonoda,N JACSll9' 5465(1997)'

3-Carboxypyridinium

chlorochrometa Oxidation of ethers.l Trimethl.lsrl, converted to carbonyl compounds b1 thrs

: Mohammadpoor-Baltork, I., pouranshinanr. S

Carbon tetrabromide. Silyl ethers are cleaved by heating with CBro in methanol,r whereas Deprotection. deacetalizationis similarly performed (in refluxing MeCN/H'O), sometimesassistedwith

Cerium(IV) ammonium nitrate. 13. 67_ 85-87;19,67-69

ultrasound.2 I-Bromoallcynes.3 Bromination of l-alkynes is achievedon reactionwith CBrr-KOH in the presenceof l8-crown-6 in benzeneat room temperature'

Functionalization of alkenes. Sqr using the combination of NII.SCN and alkenes with I,-CAN in aqueous MeCli

72

Cerium0V)ammoniumnitrate

73

rl-ee,A. S.-Y.,Yeh,H.-C.,Shie,l.-J. TL39,5249(1998). 2lee,A. S.-Y.,Cheng,C.-L.Z 53, 14255(lgg7). tAbele,8.,Rubina,K., Abele,R.,Gaukhman, A., Lukevics, E. JCR(S)618(1998).

"t:r(lgen atom of ri-,-- freferentiallY at l'.:

(-

Carbonylbis( 1,1'-benzotriazole). (Jreas.t A mixed urea is formed when the reagent is reacted with an amine in THF at room temperature,then with a secondamine in the presenceof NaH under reflux. lKatritzky,A. R.,Pleynet, D. P. M., Yang,B. JOC62, 4155(1997).

rnoistaluminain 1,1'-Carbonyldiimidazole. 13, 66; 16, 64; L8, 85 (Jreas.t A mixed urea is formed when the reagent is heated with an amine in THF, then with MeI and anotheramine.A base(e.g.,Et N) used to scavengeHI is addedin the last stage.

r::,

It is suitablefor

C \/\

rBatey,R. A., Santhakumar, V., Yoshina-Ishii, C.,Taylor,S.D. 7t 39, 626'7(1998). rFustero, dela Tone,M. G.,Jofre,V., Carlon,R. P.,Navarro,A., Fuentes, A. S..Canio,J. S. JOC S., 63,8825(r998).

a

t

-Y 1-

ftEnamino esters.2 Tertiary imines derived from ketones undergo C-acylation with which on alcoholysisgeneratesthe esters. ImrCO to give N-(B-aminoacryloyl)imidazoles Thio estersare obtained when thiols are involved in the last step.

l o-Carborane. Carbonyl protection.l

o-Carboranyllithium reacts with carbonyl compoundsto give

carbinols which are very stableto aqueousprotic acids and Lewis acids. Regenerationofthe carbonyl compounds is effected on treatment with KOH in THF-IIO (100:l) at room temperature. 'Nakamura, Y. JOC62,7809(1997). H., Aoyagi,K., Yamamoto,

3'

rr irradiation of a rJer CO (>20 atm)'r

3-Carboxypyridinium chlorochromate. Oxi.dation of ethers.t Trimethylsilyl and tetrahydropyranyl ethers are directly converted to carbonyl compounds by this reagent. rMohammadpoor-Baltork, I., Pouranshirvani, S. S 756(199?).

rncthanol,rwhereas :lrrres assistedwith t:

:,,nrvith CBr,-KOH

Cerium(IY) ammonium nitrate. 13,67-68; 14,'74-'15',15'70-72; 16' 66; 17,68; 18, 85-87: 19.6?-69 Functionalizationof alkenes. Styrenes are converted to vic-bisthioisocyanates using the combination of NHTSCN and CAN.' Iodohydrins are formed by reaction of alkenes with I-CAN in aqueous MeCN.2 Note that halohydrins are also obtained by

74

Ceriurn0V)ammoniumnitrate

exposing epoxides to CAN and a quatemary arnmonium halide.3 The addition of malonic estersto C-2 of glycals is promotedby CAN.a Ofidation of malanic acid derivatives. Hydroxylation of malonic esters5 and intramolecular cyclization of the N-alkenyl monoamides to furnish B-lactams6have been

oD'Annibale. A.. pesce,A.. Resr 'Kim. H. J., yoon. U. C.. Jung.1. . 'Takemoto, y.. yamagaa S.. Fu 'Linker, T., Sommermann,T.. Gl

reported. Cerium(Ilf

chloride heptt Hydrolysis, Alcohols r dioxolanes,2respectively. on t

Ph\_.Ph

o ll

oh ^ANr cAN veooc.rA..4 zPh + rytY MeoH An J

'11

MeOOC,,,___-/:6y"

Michael reactions. Th acceptors is promoted by CcC without solvent.l A preparauo from organocerium deri vati r.e

/-*t/\ 49"k

derivatives result Pictet-Spenglercyclization.l 1,2.3.4-Tetrahydro-B-carboline of N-trimethylsilylmethyltryptamine. from CAN oxidationof carbamates oxidative opening of [3+2]Cyctoaddition.s Species derived from derivativesby CAN can be interceptedby a remotedoublebond, aminocyclopropane The following exampleshowsN-debenzylationduring the leading to cyclopentanes. process.

\

f4cooet - C q H "r r r{X7

cAN-NaHCo3

+

MeoH-rHF

N-Bn

/---z-..-cooEt

\4:'

l*

-cooEt /flzcsHrr \ t n \..-'^---J

^ Yil=o

PhCHO +

r""

NHMe

777o

l',2'-Didehydro-2ldeoxynucleosides are converted to a Ferrier rearrangernenl' butenolide and its orthoesteron treatment with CAN in MeOH.

rBso1")rNJ

LilCe exchange.a lThe san o,a-difl uoro-B-ketophosphon N itrile aldo I re ac tions. CeClr.7HrO.6Addition of a ctl

cAN/MeoH>,rro{fl"""

'Bartoli, G., Bosco,M., Marcanrm -Marcanroni, 8., Nobili, F., Banoh. -Boruah, A., Baruah,M.. prajapan. -Blades. K.. Percy,J. M. fZ 39.gfi 'Blades, K., Lequeux,T. p., perc1.. "Xiao,Z., Timberlake, J. W. f 54. {

Cerium(IV) oxide-rutheniuul Oxidation of aldehydes.t

TBSOi' 76"/0

tNui.,v., Nair,L. G. zr 39,4585(1998). 'Horiuchi,C. A., Ikeda,A., Kanamori,M., Hosokawa, H., Sugiyama,T., Takahashi, T. T. JCR(S.) 60 (1996). 3l.-poo., N., Kazemi,F., Salehi,P. SC 27,1247(1gg'..). -Linker,T., T., Kahlenberg, F. ,/ACS119,937'7(1997). Sommermann, 5Nuir,V., Nair,L. G.,Marhew,J. TL3g,280l (1998).

'Vocanson, F., Guo, y. p., Namr. J

Cerium(IV) triflate. Op ening of three-membcta epoxides.Thus, styreneoxide n absence of nucleophiles episulfi llrunpoo.,

N., Shekarriz, M., Shirinr.

Cerium(IV) triflate

X.n \)i malonic c ..ters5 and rn',.' have been

75

6D'Annibale, A., Pesce,A., Resta, S., Trogolo, C. TL38, l82g (lgg7). 7Ki-, H. J., Yoon, U. C., Jung, Y.-S., Park, N. S., Cederstrom,E. M., Mariano, P. S. JOC 63,860 (1998). oTakemoto, Y., Yamagata,S., Furuse,S., Hayase,H., Echigo, T., Iwata, C. CC 651 (1998). 'Linker, T., Sommermann,T., Gimisis, T., Chatgilialoglu,C. TL 39,9637 (1998).

Cerium(Il! chloride heptahydrate. 14,'l 5-'17 ; 15,'72-i 3', 16, 67-68; 18, 87 Hydrolysis. Alcohols and carbonyl compounds are recovered from silyl etherd and dioxolanes,2respectively, on treatment of the latter with the Ce(III) salt and NaI in MeCN. Michael rcactions. The conjugate addition of 1,3-dicarbonyl compoundsto Michael acceptorsis promoted by CeC\.7HrO. The mixture is subjected to microwave irradiation without solvent.3A preparation method for allylic difluorophosphonatesemploys adducts from organocerium derivatives and phenyl vinyl sulfoxide, the former being obtained by n\ r!lveS

fesUlt

,'nening of x. Joublebond, rrr,,nduring the

LilCe

exchange.a lThe same organocerium reagents can be acylated to afford a,a-difl uoro-B-ketophosphonates).5 Nitrile aWol reactions. B-Hydroxy nitriles are formed in the presence of CeCl,.7HrO.6Addition of a chiral ligand (BINOL) increasesthe diastereoselectivity.

OH

OH

-cooEt /.-----1r/Usn11 \-N

+

at*

Ph

:

..........................._Ph"\,'CN t B-(+)-BINOL

CMe '-oMe

:

l

+

P6'1

-CN l

Ph

Ph

THF .78O

NHMe

rE J()nvertedto a

.

PhCHO

BuLi- CeCl3

(85 : 15) 88o/o

rBartoli, G., Bosco,M., Marcantoni,E., Sambri,L., Torregiani,E. SL 209 (1998). 2Marcantoni,8., Nobili, F., Bartoli, G., Bosco,M., Sambri,L. JOC 62,4183 (1997). 3Boruah, A., Baruah,M., Prajapati,D., Sandhu,J. S. SC 28, 653 (1998). *Blud.r, K . , P e r c y ,J . M . T L 3 g , 9 0 S 5 ( 1 9 9 8 ) . sBlades, K., Lequeux,T. P., Percy,J. M. Z 53, 10623(lgg':.). 6xiao,Z.,Timberlake. J. W. I54, 42ll (lggil.

Cerium(IV) oxide-ruthenium(Il! chloride. Oxid.ationof aldehydes.t Theoxidizingsystemconverts to carboxylicacids. aldehydes 'Vo"unron, (1998). F.,Guo,Y. P.,Namy,J.L.,Kagan, H.B. SC28,25'17

r.': T T. JCR(S)@

Cerium0V) triflate. Opening of three-membered heterocycles,t Ce(OTf). is a catalyst for alcoholysis of epoxides. Thus, styrene oxide reacts with ethanol to give cr-ethoxyphenylethanol.In the absenceofnucleophilesepisulfidesare convertedto 1,4-dithianes. ilrunpoo., N., Shekarriz, M., Shiriny,F. SC28,347(199S).

76

Cesiumcarbonate

Cesium acetate' 19r 70 Displacement of triflates'

r L-- ,*^,*anr of ^f alkTl allrvl trr triflates with Acetates are obtained by treatrnent

Mannose of l8-crown-6is advantageous' ?t-lllllf^-*ing CsOAc.Thepresence

other

hydroxygroupsprotectedundergoesstepwisedisplacements,accordingtoreactionconditions.l pivol Aco-1\zot -6gn ' pivof--\-\'/"-' 18-crown-6 OTI

T19 azoPiv L \ -n PivoS::U,oBn bft

PivO-r OAc

aco-1-Lfo. -orn

csoAc PhMe

18-crown-6

PivO-r-/v

))))

84o/"

o, [rzlr'otls

70'885(1997)' 1Suto, A',Takai'Y BCSJ K.,Yoshimoto' Cesiumcarbonate'13,10;!4''l'7-'78;15'73-75.;.18'87-88;19'70 with TsONHCOOET enonesis achievedby reaction Aziridines. a''i'iOlnution of availableby reactionof a l"t"'yf-2-alkynylaziridines are usingCsrCO,as base'rCt'itJ from the parentsalt RCft=Nts'2 The ylide is generated propargylsulfoniumytiOewifr with Cs.CO.. '

oH

a Aryl(diphenyl)silanes th€nu usingCsFto generate

.Z

cs:cog

Br

PhcH=NTs cH2cl2

Pn\J'

,

N

Ts 85%

Arybmines'3

+ l

,SiMe3

-SiMe3

|.

Cesium fluoride. 13,68; l,l A direct trant Ethers. reaction with alkyl halides il as methyl glycerate via dibtl As base. Both sulfidc CsF as a base. A route to c malonic ester and glYcidYl n

A Pd(0)-catalyzed displacement

uses of aryl halides with RNHt

"'"kilrl]'i;o,oxva,,nes.o A':'*I"b]:

iT:::T",':: ",,o;n.4-substituted The products are NMP in the air' tt"u-ting with Cs'COt in 2-methylphenols occurs * derivatives' I .2-lmethylenedioxy)benzene

F

HO

air / NMP 1 1 0- 1 2 o o

SiMe3 &fJ

.-or

CS2CO3

Eliminatian reactiots to CsFin DMF.- lt exposure with 2-trirne condensation step.

b{1-1,*'n-

tt'N'ttt cFur

i't=N

)" SOYo

54' 14105(1998)' lFioravanti,S.,Pellacani,L', Tabanella'S'' Tardella'P' t I ACIEE36'2(tee'])' r-in'L' -i, x'11-1, 2Li,A.-H.,Zhou,y.-G.,Dai,;.;;;;:i (ree't) ?L38'635e

R'A' I' P''singer' 3worr", t. "iii*""l.:;;qli' J.p.,Buchwald, (199'7)' tr*,

3343 c.-n., nitsenstat,M' A It 38'

PhCHO Mel

Cesiumfluoride

: elkYl triflates with rri ^ L:, :.tnt'late having other b: : rc'acdonconditions'r

PrvO--1OAc

^o-+fQ r.

Plvo--\sry

77

Cesium fluoride. 13, 68; 14, 79 ; 15, 75-7 6; 16r 69-7 0; 17, 6g; lg, gg_g9 19, 70_7 2 ; Ethers' A direct transformation of aryl silyl ethers to aryl alkyl ethersl is by their reaction with alkyl halides in the presenceof CsF-DMF. Monobenzylation of glycols such as methyl glycerate via dibutylstannylene acetals.2 As base. Both sulfides3and aryl ethersaare readily prepared from sulfonatesusing CsF as a base. A route to cyclopropanolactone involves the CsF-mediated reaction of a malonic ester and glycidyl nosylate.5

-oen

94"/"

MeOOC ,9 vr).

-H o

CsF/ MeCN

+ CH2(COOMe)2

f\rorus

977oee)areproducedwhen (S)-Propargylicalcohols 76,ts277.ts3 following: 74,t5o75,1s1 in isopropanol (without added 2 the ketones are treated with the ruthenium complex base).154

Cf*^Y?

/T) I N H

OMe

\r.\.-oH

Ph

Prr

HzN

(75)

(74) PPhr

(76)

-*-PPh2

Ph'.

I (6s)

NHz

S.

,Ph

,S

)-( ,-
99Vo\ via acetalssi

Chiral auxiliaries and catalysts

tt

l.l.'m\ havebeen a:.\ .\n exarnple n/(\ile

Uslng

l*

A

ri,'.c' is the regio" Continuing Er,: :h!' catalyzed I :hc rdvantageof l^.rJroperoxides.l89 r|.lir'mizedcinchona D,'n of enoneswith o: JrethYlzinc and clla tr\ e ePoxidation

coNMe2

95

4\

ff1..'H -v'-o

(.A

q""

(e5)

(e4)

The reaction of sulfonium ylides 96 with acrylic estersor methyl Cyclopropanation. vinyl ketone provides trans-2-arylcyclopropanecarboxylicesters and methyl ketones.203 Generation of the ylides with EtNP(NMe)'-N=P(NMe), as base is convenient because dichloromethane can be used as solvent. Another synthesis of cyclopropanecarboxylates proceedsby a conjugate addition and l,3-elimination sequence.2u For cyclopropanation of silyl enol ethers with diazo compounds the use of Cu-bis(oxazoline) catalysts is preferable2os(intramolecular reactions involving the ligand 97 are highly selective2ffi).Note the complex 98 was employed in a key step during a synthesisof sirenin.20?Also interesting is the observation that divergent ring systemsarise from changing catalysts.2os

{\ .rnrino acids) as i. s'l) t tartrateester) i,,: cpoxidation of dc. frtrm aldehYdes have hr' r.rltcrsPecies e.g.' I nt,'noterpenes' or.r:l()nof sulfonium cr.,,rJ. trapPedbY the

(e6)

-1*

r-rxri-f

{"

(97) R=Me,SiMeg

,.*G* V''-1J-t1 ^B? (e8)

(s3)

The chiral version of the Simmons-Smith reaction requires the presence of proper ligands for the organozinc reagent. Representatives are 99,2@ 100,210 101211 for (de cyclopropanationofallylic alcohols.Enals undergo diastereoselectivecyclopropanation >99Vo)viaacetalswith(+)-phenylexo,exo-2,3-dlhydroxybornane-10-sulfonate'2r2

96

Chiral auxiliaries and catalysts

Noe NHMs

,O fCONMe2 Bn-B. I b-',,,coNMe,

,,,NHMS

(ee)

(100)

)

c

(101)

AAolreactions. The enantioselectivity in condensationsinvolving silyl enol ethers and silyl ketene acetals (also thioacetals) has been actively pursued. Valuable catalysts include 102,213 103.2t4 Subsequent to the development of Cr-symmetric bis(oxazoline)-Cu(Il) complexes is the Sn(II) complex 104,215 which promotes anti-selectivealdol additions of silyl enol ethers to glyoxylate and pyruvate esters.

The N-sulfonyloxazabaoli ring opening condensationof r

I

-\F \rTp :

-\ (102)

N-BH

i.

003)

(104)

Reanangements. Bl q rearrangement,a chiral sidc c Highly enantioselective rc methoxybinaphthyl substinrn

Boron enolates generatedfrom ct-heterosubstitutedthioacetatesby treatment with 105 undergo highly enantioselectiveand diastereoselectivecondensations.2r6 On the other hand, chiral esters106217and 107,218and amides 10821ebehavedifferently. N-Acyl derivatives of the bicyclic isoxazolidine 109220readily undergo syn-selective aldol reactions via enol borates.

| ),,,,a \>'\-B-", : (105)

P h o

\l"V

'"-|;q{O(106)

1,3-Rearrangementwith ch fl uoroalkylamines.225O-Acylal of lb, thereby establishing a , c-amino esters from chromium CO insertion, alcoholysis, and r

ChiralauxiliariesandcatalYsts

n

o /CoNMe2 b-""cot"tM", (10e)

(108) (101)

s1r.,.rrng silYlenol ethers ur.rrJ Valuable catalysts n | ,--1

\./

b,

Fe2(CO)e |

PhH

v\e -x'

N 5

)---1

> d \

Consr Carbonylreduction. by DIBALH reduction of the &ri N-Boc pyrrolidinones is reduccd camphorsulfonatedelivers the err

MesSiCl

pnAcooH

Et3N / THF

r i ) 86"/"

The selectivereduction ofa co camptothecin.T

'Hong,B.-C., Sun,S.,Tsai,Y. JOC 62,7717(199'7).

Diisobutylaluminum hydride. 13, I l5-1 l6; 15, 137-138; 16, 134-135;17,123-125; 18, 140-l4l; 19, 128-129 Removalof bornane-10,2-sullamauxiliary.'

Due to the popularity of this chiral

coo€

coo€l

auxiliary in synthesisthe desire to recover it is high. Using DIBALH on the acyl derivatives leads to cleavageinto aldehydesand the tricyclic sultam. Deallylation. The nickel-catalyzedreaction is applicable to a wide range of amines, 5-membered N-heteroaromatic compounds, amides, and sulfonamides.2 Allyl ether cleavageis also facile and selective(with TBS, Bn, MOM, THP, Ac, Bz, Piv, An, and prenyl derivativesof alcoholsintact).3

Modificd Baylis- Hilbun ta HMPA andquenchingthe rertrc estersir cr-alkylidene-B-hydroxy from thoseobtainedfrom the nqn

Diisobutylaluminum hYdride

g1.;';. i CycloProPYlzinc

\

7nX

,no_ruo,

,

BnOJ

(dppp)NiCl2

n

\-OH

7 1"/"

Et2O

l,4-Dienes are prepared from G-(benzothiazol-2-yl)methyl ketones Elimination,a with by way of allylation, reduction of the carbonyl group with NaBHo, and reatment DIBALH-MgBr,.Thenewlyformeddoublebondofthemajorproducthasa (Z)-confrguration.

-9'

f..16r efling acyl cyanides lir.iactorily only in the

/

i-Bu2AlH

145

o

Ph

Ph< N

-l ll{D (1998).

)---\

>-s

NaBHa; -

s

| -lrr 19. 12t n::.rlt()n of c,cr'-dibromo sh:::r indanderivatives'

\_ \:

i-Bu2AtH-MgBr2

8370

conversion of carboxylic acids to aldehydescan be achieved carbonylreduction, carbonyl group of by DIBALH reduction of the derived trimethylsilyl esters.sThe cyclic with quinolinium products the of treatment further and N-Boc pynolidinones is reduced enecarbamates'6 deliversthe camphorsulfonate

I

pnAcooH *

Messicl

, il'.

i

r

l

rn^"oosiM% I #* I

pnAcno 82"k

in a synthesisof The selectivereduction of a conjugated ester is an important operation camptothecin.T

r:j

1 . 3 51; 7 , 1 2 3 - 1 2 5 ;

cooEt

cHo

i-Bu2AlH - 600

cooEt

cooEt t lpularity of this chira{1.}l ,'n the acyl derivatives c : .: \\ lde rangeof amines, u.: :r.rmides.2AIIYI ether , -\- ilz. Piv, An, and PrenYl

81%

DIBALTV Modified Baytis-Hillmnn feaction.s By reducing alkynoic esters with of ButBOTf, HMPA and quenching the reaction mixtures with aldehydesin the presence distinct stereochemically are adducts The produced. are esters o-alkylidene-B-hydroxy reaction' Baylis-Hillman normal the from from those obtained

Diisopropoxyaluminum trifl uoroacetat€

cooEt I

ilr I

OpPenauer oi

OH / HMPA'THF; |-BU,AIH

PhCHO/ Bu2BOTf

Ph

.^rl...,,,"oo=t r " l l

\rn

AI(OCOCF.) oridi conditions (room tc

rAkamanchi,K.G 2Akamanchi,K.C

61"/"

Activationofchabogens.gAmide,areconvertedtoseleno-andtellufioamides and DIBALIVTe' respectively by a combination of DIBALIVSe Esters or lactones apparently Reductive cttloroattytoion and thioallylation.to undergoinsitureductionwithDIBALHandtheresultingaldehydesreactwith functionalizedallylictitaniumandboronreagentstoprovidethecouplingproducts.Such products are useful for the synthesisof vinyloxiranes' HCA 80' 1319(1997)' rOppolzer, P" Rosset'S'' De Brabander'J' W., Darcel,C', Rochet, 2funigu"hi,f., Ogasawara' K' TL39' 4679(1998)' 3Taniluchi, K' ACLEE3T'1136(1998)' T., Olasawara, acalo,V., Nacci, A..TL39,3825(1998)' tiiunarur"nt*, S.' Kumar,M' S',Muralidhar,B'TL39'909(1998)' 6cossy,J.,Cases, M., Pardo,D'G' SC27'2'169(199'l)-' Tchuuun,S. P., Venkatraman, M S TL 39' 6745 (1998)' 8Li,c., w"i, H.-X.,willis, s. rL 39' 4607(1998)' eLi, G. M., Zingaro,R.A. .ICS(P/)641(1998)' loHertweck,C., Boland'W. EJOC2143(1998)'

DiisoproPYl Pbocl Protection ol t which is formed in lBrands,K. M. J . \\'

DiisoproPYl sulllt Cyclic sulfla yield. It reacts u.id

rKing,S. A., PiPr\-|

DilauroYl Perori Hydrodesulfi of xanthatesin rel

4-Subst'tua tion on treatmct

tetrahYdroisoqut Diisobutylaluminum isopropoxide' to glve quantitative This reagent effects reduction of cyclic ketones Rediction.t yields of the more stable alcohols' 'Chu,J. S.,Kwon,o. JOC 62,3019(1997)' 8rt

Diisobutylaluminum phenylselenide' "*";,;-;;h.t S"qu"ntiul reactions of

aldehydes with

amines and ethyl

chloroformatedeliverunsaturatedcarbamateswhichcanpickoffthePhSegroupfrom precursorsfor radical reactions' i-BurAl-SePh. The MSe-acetalsare useful lstojanovic, P. TL37,9199(199'l)' A., Renaud,

'Liard, A.. quicla rLi.d, A.. qrri.h icholleton. \.. z:

Diisopropoxyaluminum trifl uoroacetate' Reductions.|Preparedbyreacting(,-Pro)3Alindichloromethane.withtrifluoroa materials, the aluminum salt behaves as acetic acid followed uj removal of volatile

Dilithium 2Jr Diek-AId. conjugatedcart

reducingagentforaldehydesandketones.Whileexcellentyieldsofalcoholsareobtained

l\ practicall\ ln

frommostcarbonyl.ompound,,theonlyexceptionissalicylaldehyde(33Vo).

Dilithiurn 2,2'-methylenebis(4,6-di-t-butylphenoxide)

;ooEt

In combination with p-nitrobenzaldehyde, (i-PrO)t Oppenaueroxi.dation.2 AI(OCOCF3) oxidizes secondary alcohols but not primary alcohols under the defined conditions (room temperature). lAkamanchi, B. A. St 3'71(1991)' N. R.,Chaudhari, K. G.,Varalakshmy, 2Akamanchi. B. A. ZL 38, 6925(1997) K. G., Chaudhari,

!"

- JnJ tellurioamides lr-:()nes apparently ldchrdes react with rplrnr products.Such

:::.r 1997).

Diisopropyl phosphite. Protectionof amino acids.l N-Phosphorylation is performed with (l-PrO)rP(O)Cl which is formed in situ from (r-PrO)2POH and NaOCl. rBrands, K., Williams,J. M., Dolling,U -H', Reider,P' I' TL39' 9583(1998)' K. M. J.,Wiedbrauk,

Diisopropyl sulfite. Cyclic sulfites.' The reagentis availablefrom isopropanol,thionyl chloride in95Vo yield. It reactswith diols in a transesterificationprocessunder the catalysis of MsOH. lKing,S. A., Pipik,P.,Conlon,D. A., Bhupathy,M.SC27'701 (199'7)'

Dilauroyl peroxide. By adding dilauroyl peroxide in small portions to solutions Hydrodesulfurization.t ofxanthatesin refluxing isopropanolthe sulfur-containingfunctional group is removed. 4-Substituted a-tetralones. 3-Aroylpropyl xanthatesundergo desulfurative cyclizaSimilarly, 1,2,3,4tion on treatment with dilauroyl peroxide in 1,2-dichloroethane.2 -ones are prepared.l I tetrahydroisoquinolinx 1,, 9l\'€ quantltatlve

o

o

aY^\ ,rN,.l

dilauroylperoxide

Nc b< s

Jnlnes and ethYl ihc PhSe group from |;:]' tn\

F:hrne with trifluoroDunr \alt behavesas a rf r.-rrhols are obtained ,rjc

1-lgr).

ctcH2cH2cl

4Y> l l t arl^W

I-cN

A

oEr

l

5O-/o

' Li*d, A., Quiclet-Sire,8., Zard, S. Z. TL 37' 58'7'7(1996). Zliard, A., Quicletsire, B.,Zard,S.Z. TL38, 1759('1991). 3cholleton,N., Zard, S.Z. TL39,'7295 (1998).

Dilithium 2,2'-methylenebis(4,6-di-l-butylphenoxide). This salt acts as a bidentate Lewis acid to activate Dinls-Alder reactions.t conjugated carbonyl compounds toward dienes. Note that lithium 4,6-di-l-butylphenoxide is practically ineffective under the same conditions.

148

(3-Dimethylarninopropyl)dimethylgallium

o

ll r

tl

4\aY

\rV

tl

o

0,o PhMe

* \=' L

(1)

i ,

L O

H (.)

65Yo

750/"

rhc.i nrethod by avoiding or. . hcatinga ketonewith

rRagoussis, N., Ragoussis, V. JCS(\l)3529(1ggg). 'Mairi, G.,Roy,S.C. TL3g,4g5(1997). Guiso.V.,Procaccio, C..Fjzzano, M. R.,piccioni,F. TL3g,42gl(lgg7). stumpt,A.. Jeong,N.. Sunghee, H. SL2O5(lgg7t. Dimethylsulfoxonium methylide. 14, 152; lS, 147 16, I 46; 17, 126_127;lg, I 48; 19, I 39 ; Polyhomologation.t The ylide provides the methylene unit in chain extension of triorganoboranes.Besides oxidative workup to generate alkanols, the replacement of the boron atom by a hydroxylated carbon on reaction with dichloromettryt mettryt ether gives compounds with trident carbon chains.

I .rr:n rldehydesin DMSO nr--rrtedacids. r.:. homoallylic,benzylic rtri:rple\. 79 -87 Vo);those

Et3B + Mezfl-cxz- + .r hich are formed by l- .r..1 I.l-diol systems,ue 5

ll

o

[R(cH2)n]38 :::""t, ct3v'Oli

;

NaoH,HooH

156

Diorganocadrniums

lshea.K. J..Busch, B. B.,Paz,M.M.ACIEE37'1391(1998).

o*o

2,4-Dinitrobenzenesulfonamide. Acid chlorides are converted to nitriles by heating with the arenesulNitriles.t fonamide and EqN in THF.

rAponick,

A., McKinley, J. D., Rabcr.

rHuber.V. J..Bartsch, R. A. f 54,9281(1998).

2,4-Dinitrobenzenesulfonyl chloride. Secondary arnines.t Primary amines form sulfonamides which can be alkylated in the conventional manner or using Mitsunobu reaction. The sulfonyl group is removed by treatment with mercaptoaceticacid and EtrN.

ai

oJ ftsozcl or",,.g*o,

RNH2

,i'\rt-nHn

o,"'\rL*o,

1,L-Dioxobenzo[D]thiophene'] Amineprotection.t Carb., protectionis accomplished b1'rcz

B'x -*

,r*l'*i"

o,*-\Aruo,R

\.,.^-d r

BuLi: HCHO RCO3H

RR'NH

rCarpino,

The sulfonamides undergo functional group exchange on hydroxamic acids' and RzNC(=S)SH' in the presence of acid' reaction with thiolacetic the sulfonamides with dithioacids affords thioamides. of cesium carbonate.Reaction Amides and ureas.2

rFukuyurnu, M., Jow,C.-K.,Hidai,Y., Kan,T' TL3E' 5831(1997)' T., Cheung, 2Messeri, N. C. O. TL39' 1669'1673(1998)' D. D., Tomkinson, T., Stembach,

N,N'-Dinitroethylenediamine. The silylation of propargyl alcohols with hexamethyldisilazide is silylation.t

L. A., Philbin, M., Isrnarl. El-Faham, A., Riemer, C., WarrrsL I

Diphenylacetyl chloride. Thc Hydroxylprotection.t (pyridine,-10'). Recoveryofthc achieved by free radical brominat rSantoyo-Gonzalez, F., Garcia-Calr A. S 97 (1994).

calalyzedby the nitramine. rMedvedeva. L. P.' Memina,M M' RJOC34' 127(1998)' A. S.,Yazovtsev,I' A., Safronova,

Diphenyl diselenide.13, 125: lt, Ox azoline s and oxazo lin -2-o addition of RCN to alkenesin thc 1

Dinitrogen pentoxide. 18, 150 Silyl ethers and silylamines are converted to nitrate esters and Nitrodesilylation.t nitramines, respectively, at about 0".

by PhSeSePh.

rMilla..R. W.. Philbin,S. P. r53, 43'll (1997)'

Diorganocadmiums. Addition of RrCd to p-benzoquinonesis a general reaction' p-Quinols.t

Ph

\:

0

Diphenyl diselenide

o{tso

o#*

Me2Cd THF

71"k r\ heating with the arenesullAponick, A., McKinley,J. D., Raber,J. C.,Wigal,C.T. JOC 63,2676(1gg8).

o.i'r :Jes which can be alkYlatedin r. , :..: .ulfonyl group is removedbY

o.. ao ^ .'yt-*.--*

1,1-DioxobenzofD]thiophene-2-methoxycarbonyl chloride. Arnine protection.t Carbamate formation from amines and the reagent 1 is facile, protection is accomplishedby treatment with piperidine.

@

BuLi; HCHO;

rzY\ *,{

RR,NH

(1)

_ .. a4*or"' g '..rctional grouP exchange on g ft \Cr=S)SH, in the presenceof d::.-. ,e tds affords thioamides. Ii -t{ r.ll (1997). lM. "-l t1998).

0.. - rr ith hexamethyldisilazide is

n:= \1 \1. RJOC34,l2'l(1998).

/ococl ^;'

RCO3H

'Carpino,L. A., Philbin,M., Ismail,M., Truran,G. A., Mansour,E. M. E., Iguchi,S., Ionescu, D., El-Faham,A., Riemer,C., Warrass,R., Weiss,M. S.JACS119,9915(199'l).

Diphenylacetyl chloride. Hydroxylprotection.t The primary hydroxyl group ofsugars is selectively acylated (pyridine, - I 0o). Recovery of the alcohol without affecting other groups such as acetoxy is achievedby free radical bromination (NBS, hv) and treatment with thiourea. rSantoyo-Gonzalez, R., Vargas-Berenguel, J., Robles-Diaz, F., Garcia-Calvo-Flores, F., Isac-Garcia, A. S 97 (1994).

Diphenyl diselenide. 13, 125; 18, 15 1- 152; 19, 140-l 4l Oxazolines and oxazolin-2-ones.t These heterocyclesare obtained in the oxidative addition of RCN to alkenesin the presenceof (NH)2S2O8and CFTSO,H,which is catalyzed by PhSeSePh.

l. ::. -()n!erted to nitrate esters and Ph Ph

PhS€-SePh - CF3SO3H (NH4)2S2O8 aq. MeCN

F:-..- :. J generalreaction.

600

158

Diphenylphosphorazidate

1,4-SultenyI-2-alkenes.2 Conjugated dienes are dithiolated with the assistanceof PhSeSePh andlieht.

+

PhS-SPh PhSe-SePh

,nr^.,A,rrn. r^#t' 90%

'Tiecco, M., Testaferri, L., Marini, F., Temperini, A., Bagnoli, L., Santi, C. 'Ogawa, A., Obayashi,R., Sonoda,N., Hirao, T. TL3g,1577 (1998).

Diphenyl sulfoxide-triltl Glycosides. Actir. significant becausethe res with O-, .l-, N-, and C-nu (89Va) and oligosacclu 2,4,6 -frmethylphen y l atioo

glycosylation with gl1.c ( 1,2-anhydropyranosidesI I

activation and brief trearm completes the glycosylario

sc 27,4r3r(1997).

aoBn

Diphenyliodoniumtrifl ate. a-Phenyhtiont Addition of PhrIOTf ro copper enolatesof ketones serves to introducea phenylgroupto theu-position.

o tl .) \-,

o

LDA/ THF ;

..'..".................* CuCN;

tl /-"'/Ph

t

l

\./

Ph2toTf 50o/o

'Ryan, J. H., Stang,P.J. fL 38,5061(1997).

Diphenylphosphine oxide. Deoxygenation.l Alcohols are convertedto xanthatesand then exposedto PI5P(O)H (with di-l-butyl peroxide also present)in refluxing dioxane to complete deoxygenation.The phosphorusreagentoffers an alternative to the organotin hydrides. rJang,D. O.,Cho,D. H., Kim, J. SC2E,3559(1993).

Diphenyl phosphorazidate. a-Amination.' Carboxylic acid derivatives are converted to the o-amino acids by treatment of the lithium enolateswith (PhO)rPON,. rvillalgordo, M., Linden,A., Heimgartner,H. HCA79,2l3 (1996). J.

Bno-N-Q BnOl-4

lGarcia, B. A., Poole,J. L.. G,r 'Di Bussolo, V., Kim. y.-J..Gn

O,O' -Di(2 -py ridyl) rhiocer Esterifuatian.' Thc hinderedalcohols(includin

'suitoh, K., Shiina,I., Mukailr

NrV.Disuccinimidyl carbc Preparation.t The N-hydroxysuccinimide *.irh

Mixed carbonales.2 , provides reagentfor N-^lkot

lPereira, D., Hai, T. T., Nelso. 'Kundu, B., Shukla.M.. Shutl

lV,t-DisuccinimidylcarbonatelS9 rE -:::hrolatedwith the assistanceof

\

'- /,SPh -

I

lsPh

,nr^Yz\ I

90%

Diphenyl sulfoxide-trifl uoromethanesulfonic anhydride. Glycosides. Activation of anomeric hydroxyl groups with phrSO_TfrO is significant becausethe resultant speciesreact, often stereoselectively and in- good yields, with o-, s-' N-, and c-nucleophiles including the hindered N-(trimethylsilyl)pivalamide (89vo) and oligosaccharides. Elaboration of c-glycosides is illustrated by 2,4'6-timethylphenylation (81%o).rThe reagent combination is also useful for etfecting glycosylation with glycal donors2 in which the formation of grycal epoxides (l'2-anhydropyranosides) by oxygen transfer from dipenyl sulfoxide is implicated. After activation and brief treatment with MeoH, a ZnClr-promot-edreaction with nucleophiles completes the glycosylation.

r:rtr. C. SC27,4131(1997).

l: .

aoBn

eno-$-Q pgt': :n,rlates of ketones seryes to

BnO-r...-=r

Ph2s=o - Tf2o 2,6-di-t-butylpyridine ; MeOH, Et3N; 1,3,s-trimethoxybenzene

OMe

BnO BnO

ZnCl2 810/"

a

:r'^ 50or

O::r. ,rndthenexposedto PtrrP(O)H ri:.r :,r completedeoxygenation.The D: :.; Jndes.

:ned to the u,-amino acids by

! . *

'Ga."ia, B. A., Poole,J. L., Gin, D. y. JACSrtg,7s97(199't). 'Di Bussolo,V., Kim, y.-J., Gin, D. y JACS120,13515 (1998)

O,O' -Di(Z -py ndyl) thiocarbonate. Esterification.' The reagent is an excellent mediator for esterification of acids with hindered alcohols (including I -adamantanoland isoborneol) in the presence of DMAp. 'Suitoh, K., Shiina,I., Mukaiyama, T. CL6jg (lgg8\. NyV-Disuccinimidyl carbonate. Preparation.t The reagent is obtained in large scale by reaction of N-hydroxysuccinimide with triphosgenein THF at 0. (using Bu.N to remove HCr). Mixed carbonates-2 Dispracement of one succinimidoxy group with an alcohol provides reagentfor N-alkoxycarbonylation of amino acids. rPereira, D., Hai,T. T., Nelson,D. SC2g,4109(199g). 'Kundu, B.. Shukla.M.. Shukta.S. JCR(S)427irgg4t.

lGong,

Y. D., Tanaka, H., Iwasawa- \.

Ethyl (diarylphosphono)acetet Emmons-Wadsworth reactb (Z)-selective manner(8 examples Ethoxyamine. is throughMichaeladditionfollowed from nitroalkenes 1,2-Diamines,t A synthesis by catalytichydrogenation

M"?o",

rrY':-\

NHz

r,Y/

E1ONH,. HCt - NaHCO3/THF;

H2, Pd/C

i

ErOH

\/

l

t - NHz

Vr"oU

l

88%

tI-ugu*u,

cooEr

K., Hata,8., Yamada,T., Mukaiyama,T. CL291 (1996).

cr-Ethoxyvinyllithium-HMPA. Deprotonation' This reagentbehavesdiffferentlyfrom manyotherlithiumbasesin at allylic andbenzylicsites. deprotonation

tAndo,K. Joc 62,tg34(tggl). Ethylenesulfate.15, 105-107:l& Alkoxyethanols.t Alkylaoc intermediates.

NaH/DMF:

..Ph

P-a

;.,,{--.*,)',,,..oMe

s-BuLi- HMPA; Mel / THF - z8o

P-l

EtO I

.Ph

?",

1.,A:r2'",,..oMe

HMPA:

Mel / THF - 78o

vn OH y--rPh

[]uo'

;aA:r22",'oMe 81v.

'wei,H., Schlosser, M. CEJ4,173g( l9

Ethyl 1-hydroxy-lH -t,2$-fiiaz* Couplingof aminoacids.t T

rShirnuno, A. I. ?I 38,5415(lgg'7). M.,Meyers, Ethylaluminum dichloride. 19, 143 Disproportionationofa,arylalkenylethers.' The intramolecularversion of this (5- and6-membered). reactionis suitablefor the synthesisof l-arylcycloalkenes

o

J

EtAtCt2 cH2ct2

qo lJiang,

L., Davison, A., Tennant, G.. Rra

-

Ethyl l -hydroxy_| H -1,2 J-triazole-4_carboxytate rGong,

Y. D., Tanaka,H., Iwasawa, N.,

Narasaka,K. BCSJ7l,2lgl

099g).

Ethyl (diarytphosphono)acetate. Emmons-Wadsworthreactions.t These est(trs react with aldehydes (Z)-selectivemanner .*u-pr"s, in 1a Z:E > 93:7).

cooEt M e O n l "s^/

I

t

rY')^

f",NHz

--

-

|

v

\-Pn 100%(Z :F= 96 : 4)

88%

lr.:

SOOEI

PhcHo/THF

Vrr"o&

,Aa\, i l l

Triton-B

::()m many other lithium basesin

rAndo, K. Joc 62, tg34(tgg.l). Ethylene sulfate. 15, 1 0 5 - 1 0 7 ; 1 8 , 158 Alkoxyethanols.l Alkylation offunctionalizedalcohols canleadto usefursynthetic lntermediates.

NaH/DMF;

t

:\ rJi

OH

P-$'n THF :8"

-

t

o.

-

o*o"

dsot

{'2'",.-ottte

t-BuOK

'5,\ 6.=-;o

'Wei, H.,Schlosser, M. CEJ4,1738(199g). Ethyf l -hydroxy- | H _1,2,3_triazole_4_carboxylate. Couplingof aminoacids.t fn" ,"ug"nt f l, a nrgfrtyefficientcoupling agent. Jt. rnrramolecularversion of this irls- i- and 6-membered).

N--f N.2

,cooEt

N' I

,.nD

OH (1) rJiang,

L., Davison, A., Tennant, G., Ramage,R. T 54,14233 Qggg\.

l-Ethylpiperidinium hypophosphite-2,2'-azobis(isobutyronitrile)

Ethyl mandelate. Phenylketones.l In employingethyl mandelateas a benzoylanionequivalentthe two reactionstepsneedingimplementationare alkylation(LDA, RBr, or RI) and flash vacuumpyrolysisat 650'.

\ "6J^'B' v OMe

tAitk"n.R.A.,Thomas, A. w. sL 293(1997). Ethyl methylthioacetate. Homologationof alkenes.t Under photochemicalconditionsthe radical addition carboxylicesters.Many functionalgroupsaretolerated' giveshomologated

v

.'

+

p.Ethylthiopropionyl tetnnr Arylvinylkennes.t Eb substitutionwith EISCH.CH. trifluoride) at low temperarr followedby treatmentwith a n

nu

""a1ott 5

tM"Cagu", R.,Pritchard, R.G..Sr

' MecN

tl-"b"d"u, rDeng,

M. V., Nenajdenko. \' (

L. X., Kutateladze,A. G. ZL 38, 7829 (199"1).

Ethyl p-nitrobenzenesulfonyloxycarbamate. AZiridines. Aziidine-Z-carboxylicesters are formed at room temperatureby in the presenceof CaO.r Similarly' reactionof conjugatedesterswith NsONHCOOET way.2 reactin thesame nitroalkenes amination.3 y-Silyl a,p-unsaturatedesters are aminated at the Desilylative by rnigrationof thedoublebond. cr-positionaccompanied

Ethynyltributylstannane. Diels-AIde r reactio ns.: bearingan alkenylstannane tr equivalentfor acetyleneandsu lSauer,

J., Heldmann, D. K. fL t.

Europium tris[di(perfl uora 2 wid Epoxide opening.t

i}-"oors *(-.,"",

cao + NsoNHCooEt ;[d

COOMe NHCOOET

on reaction with acid chlori&s Michael reaction.2 Thc of the Eu complex proceeds dr

660/.

lcarducci, M., Fioravanti,S., Loreto, M. A., Pellacani,L., Tardella,P. A. TL37'3777 (1996)' 2Fioravanti, S., Pellacani, L., Stabile, S., Tardella, P. A.' Ballini, R' 7L 38' 3309 (1997)' 3loreto, M. A., Pompei,F., Tardella,P. A., Tofani, D. f 53, 15853(1997).

1-Ethylpiperidinium hypophosphite-2,2'' azobis(isobutyronitrile). radicalcyclizationof Radicalcyclization.t The bestresult for the stereoselective andAIBN hypophosphite with the p-propargyloxy-cr-bromoketones is obtainedby heating in toluene.

o. \\ \ ) +

o )

'Taniguchi, Y., Tanaka, S., Kitaml -Hanyuda, K., Hirai, K., Nakai. T. .

/rmtnle

Europium tris[di(perfl uoro-2-propoxypropionyl)lmethanate

I

la:: -r. a benzoyl anion equivalent the r\.r::,,n rLDA, RBr, or RI) and flash

AIBN

trr

\

' N ( \_J'U

o

HcPOt

phMe^

.4 ,P oY{\ OMe 74Yo

n'.:.i. ;onditions the radical addition Ll. ::.'Jps are tolerated.

'McCague,

p-Ethylthiopropionyltetrafluoroborate. Aryl vinyl ketones.t Elechon-rich aromatic compounds undergo electrophilic (formed in situ from the acid fluoride and boron substitutionwith EISCFICH2COBF4 trifluoride) at low temperature.The productsfurnish ATCOCH=CB after methylation followedby treatmentwith a mild base.

!

c.'

tl-eb"d"u,

l: t

rred at room temPerature bY - ::c presenceof CaO.r SimilarlY,

tr:'- i

R., Pritchard,R. G., Stoodley,R. J., Williamson, D. S. CC 2691 (1998).

!'slers are aminated at the

M. V., Nenajdenko,V. G., Balenkova,E. S. S 89 (1998).

Ethynyltributylstannane. Diels-Alder reactions.t Thereagentundergoes to giveadducts [4+2]cycloadditions bearingan alkenylstannane moiety. Accordingly, it can be consideredas a synthetic equivalentfor acetyleneandsubstituted alkynes(aryI,acyl,andhaloalkynes). rSauer, J., Heldmann,D.K.TL39,2549

(1gg8\.

Europium tris[di(perfluoro-2-propoxypropionyl)]methanate. 18, I 59- I 60 Epoxide opening.l With Eu(dpm)3 as catalyst; epoxides give B-chlorohydrin esters COOMe NHCOOET

on reaction with acid chlorides. Michael reaction,2 The reaction of ketene silyl acetalswith enones in the presence of the Eu complex proceedsalmost exclusively by the conjugate fashion.

bO'/o

(1996). .l::i: lr. P.A. TL37,3'7'l'7 R rL 38.3309(1997). L !-r '.
--\

-SiMe3 imidazole/ DMF

--:^c=J

15oo

Allylation of carbonYl comPo and tin in promoting allYlation of scope of the indium-promoted all' of both reacting componens. ( intermediates. Allylation of unP

selection to furnish sYn-I.2-amr witnessed.lo

NHz

grN

A"ro

TIPSO 82"/o

ISugai,

M., Tanino, K., Kuwajima, l. SL 461 (1997).

Indium. 14,8 I ; 16, I 8 I - I 82; 18, I 89; 19, l7 | -173 Reductions. Nitroarenesare reduced by indium powder in aqueousethanol containingNH4Cl.l Benzofusedheterocyclessuch as quinolineand quinoxalinesuffer reductionat theheterocyclicmoietyon prolongedheating.2

In- Hd

Br

PhCHO

NHr

In - NHaCI aq. EIOH

t -

an

While y-selectivityis usualll 4-chloro-2-butenylbenzyl ether the derived allylindium reagenla An intramolecular reaction dr

Nsr\Z

99o/o

In the presenceof indium, Wurtz coupling of halides3and pinacol Coupling reactinns. coupling of aromatic aldehydes,athe latter with assistanceofultrasound, have been reported. Aryl-substituted vic-dibromides (both meso ^nd d/ isomers) Debromination.5 undergo debromination with indium in refluxing methanol to afford (E)-alkenes.

o.,

B\Xhd /-'. Pri

Br

B,\

Br

ts-.te r

o

ln / MeOH

-X-/d P{-

,-\

sr

Allyl ketones. Reactton o bromide in water is a convente

195

Allyl transfer to alkynes and activated.alkenes. The synthesis of 2-substituted 1,4-dienesfrom l-alkynes and allylbromide (12 examples,75-90Vo)6ismediated by indium in THF at room temperature. Alkylidenemalononitriles also accept an allyl group in a similar reaction (water is presentin the reaction medium in thesecases.;.? Generally, indium is more effective than zinc Altylationof carbonylcompounds. The and tin in promoting allylation of carbonyl compounds in the solvent-free condition'd scope of the indium-promoted allylation has been probed widely by varying the structures Sr unit are prone to fragment l . 1. compoundsbY this method

of both reacting components, thereby also making available many useful synthetic intermediates. Allylation of unprotected o-aminoaldehydes is subjected to diastereoselection to furnish syn-I,2-aminoalcohols.e1,4-Asymmetric induction has also been witnessed.lo

N Hz =

A"*o

+

/ ;\ / / ./z Br' \/

In - NHaCI

!,H,

/':/W 6H 55"/"(syn: antl = 99 : 1)

In- H2O

-"JG;,.Y +

m lr,rrder in aqueous ethanol qu:n,'iine and quinoxaline suffer E .

h\_

39% r'-,, -rruptingof halides3and pinacol f, u.r,rround, have been rePorted. foth meso and d/ isomers) r n. :,' afford (E)-alkenes.

tt)--a.

--

,:..

ta-/-o

R=H

797"

( ' 1 3: 8 7 )

R=TBS

83%

(76 : 24]-

(e'g., While lselectivity is usually observedin reaction with substitutedallyl halides -propene behavesdifferently as 4-chloro-2-butenylbenzyl etherrr),3-bromo-3,3-difluoro-I r2 the derivedallylindium reagentaddsto aldehydeslike s,cr-difluoroallylcarbanion An intramolecularreactionthat resultsin ring expansionis also valuable.rl

zt'

o,

Rov\/VPh li l l o I H

o ^{ -cooet L_ I

o Br

I n / a q . H C l ,T H F ;

a\€\

/ \ \,___r,/.-cooEt 541"

Br

with allylindium Allylketones. Reaction of acid chlorideslaor 1-acylpyrazolesrs The divergent ketones. allyl of for synthesis method is a convenient bromide in water

behavior of acylpyrazoles and acylimidazoles can be aftributed to the stabilization of the tetrahedralalkoxyindium speciesfrom the former compoundsby chelation with the second nitrogen atom. Decomposition of the correspondingproducts from the acylimidazoles gives ketones which are susceptibleto further reaction.

!')

I n/ H z O ,

'o..,r"?

V,,

tsch-, T.-H.,Lu, w. rz 39,86o5( l99t r leFuji*".u, N., Yamamoto,Y. TL 39.4719r 2oZhan,z.,Zhang,Y. sC 28,493(1998). "W-g, L.,Zhang,Y.,/CR(S)588(l99Er' 22Hoppe, G. C., Murn1. H. A., Lloyd-Jones,

>80%

O.\

,N-\

/^--*u, t

V,,'

l

o.

In/ H2O

.^)=^ (, >95%

Al$lation of imines and nitriles.

(S)-Homoallylic aminesare accessibleby addition

of allylindium reagentsto imines derived from valine methyl ester.r6Enaminesalso undergo allylation in the presenceof acid (HOAc) with which iminium speciesareformed in situ'r7 I8 Sulfoniminesreactsimilarly. Reaction of nitriles containing an electron-withdrawing group at the cr-position leads to enaminesle Auyt sutftdes and sulfones. Displacement of bisulfite anion from RSSOrNa20and chloride ion from RSO2Cl2rusing allylindium reagentsin water has synthetic value. 3-Butenylcyclopropanes,22 The indium-promoted reaction of enones with allyl bromide gives cyclopropane derivatives in which two C,H, units are unified to effect reductive gem-dialkylation of the carbonyl group of the enones,when the initial adductsare treated with LiBr before workup. Otherwise the normal allylation products prevail.

o pn*pn

Brt \V

Indium(IID chloride. 19, 173-l'1 4 Isomeizption of ePoxides-t Ttr conversion of epoxides to carbonyl cu Reductive Fricdel'Crafrs alk lttu

InClr-catalyzed alkylation with aldcttl chlorodimethylsilane). The laner prat Aldol reactions. The Mukail-an in water.a'5

ftAmino ketones and esten-o T (or silyl ketene acetal) with formaldcttl

OSiMe3 I +

PhcHo

"n\

Formadq Conjugate additions. prrt addition Michael by the pounds8 -Alder -' tio ns reac Diels Imino derivatives. phenanthridinone

ln / THF; LiBr

,

8Yi. x.-H., Haberman,J. x., Li, C.-J.5c 2| ePnqu"tt", L. A., Mitzel, T. M., Isaac. M- B. loPuqu"tt", L. A., Bennett, G. D., Chhatnrdl ItMoriku*a. T., Narasaka,T., Sakuma C - 1 l2Ki.iha.u. M.. Takuwa, T., Takizawa- S . \l 13Hube.tnan,J. X., Li, C.-J. It 3t' 4735 I l9r 'oYaduu, S., Srinivas,D., Reddy,G. S.. Br J. tsBryun, V. J., Chan, T.-H. ?L 3E,6493 t 199 l6loh, T.-p., Ho, D. s.-c., Xu, K.-c.. Sinr. I rTTussa. L.. Lebreton, C., Mosset, P. CA lO

Et2o; H2o 83%

rMoody,C. J.,Pius,M. R. sL 1028(1998). 'Moody, C. J.,Pius,M. R. Sr lo29 (1998). 3Ranu. A. TL39,9557(1993). B. C.,Dutta,P.,Sarkar, al-itn,H. J.,Keum,G., Kang,S.8., Chung,B. Y., Kim, Y. TL39' 436'7(1998). sRanu,B. C.,Guchhait, A. CC2113(1998). S. K., Sarkar, oRanu,B. C., Majee,A. CC 1225(199'7). ?Wang,L., Sun,X., Zhang,Y. SC28, 3263(1998).

Ph

* ? *I I Ph

Indiumfitr) chloride

bu:r.l to the stabilization of the x. ^r chelation with the second f . i'"flr the acylimidazolesgives

.C

/^,,r'2 \.\ r 8 0o/o

tYi. X.-H.. Haberman, J. X., Li, C.-J.SC28, 2999(1998). epaquette, L. A., Mitzel,T. M., Isaac,M. B., Crasto,c. F., Schomer,w .w. Joc 62,4293(1997). (1998)' r0paquetre, A., Isaac,M. B. JOC 62,3370(1997),63,1836 G. D.,Chhatriwalla, L. A., Benneu, rlMoriku*u, T., Narasaka, T., Sakuma,C., Taguchi,T. CPB 45' 1877(1997)' t'Ki.ih*u. M.. Takuwa,T., Takizawa,S.,Momose,T. TL38'2853 (1997). r3Hub".m-,J. X., Li, C.-J.TL38,4"135 (1997). laYudau,J. S.,Srinivas,D., Reddy,G. S.,Bindu' K. H. fL 38' 8745(1997)' r5Bryan,V. J.,Chan,T.-H. rt 38, 6493(199'1). t6ltoh.T.-p.,Ho, D. S.-c.,Xu, K.-c., Sim,K.-Y.,Li, x'-R. TL38'865(1997)' ltTurru, L., Lebreton,C., Mosset,P. CEJ l0@ (199'l). lschan,T.-H.,Lu, W. ?L 39,3605(1998). 1eFu.litn*u,N., Yamamoto,Y . TL 39,4729 (1998). 2ozhan,Z.,Zhang,Y. sC 2E,493(1998). ttwung, L.,Zhang,y.JCR(S)588(1998)' 22uopf",H. e.,lioyd-Jones, T' M', Walsh'K'E'ACIEE37' 1545(1998)' C. C.,Munay,M., Peakman,

chloride. 19, 173-17 4 Isomerizption of epoxides.l The Lewis acidity of InCl is exploited for the conversion of epoxides to carbonyl compounds. Benzylic alcohols obtained from the Reductive Friedel-crafts alkylation.z be reduced in situ by a hydrosilane (e'g'' can with aldehydes InClr-catalyzed alkylation catalyzed by Lewis acid. process is also chlorodimethylsilane). The latter is performed either solvent fred or reaction aldol Al.dol reactions. The Mukaiyama

Indium0lD >95o/"

a::.:nL'\iue accessiblebY addition r . :.:e r. 16Enaminesalsoundergo n -"r .peciesareformed in situ.lT tc ::,,up at the cx-positionleadsto rl:::r .rnionfrom RSSOrNa2oand 1 .. .,:crhas sYntheticvalue' I ::.r.ritrn of enones with allYl ( ll. units are unified to effect n ":.c.. g hen the initial adductsare [.r ..rti0nproductsPrevail.

in water.a'5 condensationof a silyl enol ether ftAmino ketones and esters.6 The Mannich-type is catalyzed by Inc\ in water. amine (or silyl ketene acetal) with formaldehyde and an

InCl3/

pSiMe3 " A + P h C H o + P h N H 2

H2O

O

NHPh

i l l Ph

Ph/\ 75"k

Formation of B-aminonitrilesT and l,5-dicarbonyl comconjugateadditions. pounds8by the Michael addition processesare mediated by InCl' Imino Diels-Alder reactions.e The catalyzedreaction servesto form quinoline and phenanthridinonederivatives. 83%

Ph

* ? *I !9 r:rrl ( 1998)

I Ph

lnOl3/ MeCN

198

Indium(III)iodide

2,4-pentadienyltributylstannane with Pentadienylation.to The reaction of a-alkoxyaldehydes is 1-selective and syn-selectivewhen promoted by InClr. Other regioand diastereomersare formed using other catalytic systems.

oR'

l

R

CHO

+

V"Vz'usnBus

lnO[ / MeCN + R

OH R ' =B n

76/0

R'=TBS

78ok

Dichloroindium hydride is formed when InCl, is reduced with BurSnH. The reagentcan be used to reduce aldehydes,ketones, and alkyl halides. Reductians.tt

lRanu,B. C., Jana,U. JOC 63,5212(1995). 2Miyai,T., Onishi,Y., Baba,A. TL39,6291(1998). 'Kobayashi, S. fZ 39, 1579(1998). T., Nagayama, S.,Busujima, ol-oh.T.-P.,Pei,J.,Koh, S.-V.,Cao,G.-Q.,Li, X.-R. ?4 38, 3465(1997)sl-oh,T.-P.,Chua,G.-L.,vittal, J. J.,Wong,M.-w. CC861(1998). "Loh,T.-p.,wei, L.-L. rL39,323 (1998). tl-oh,T.-p.,wei, L.-L. sL 975(1998). 8I-oh,T.-p.,wei, L.-L. r54,7615 (1998). eBubu,G., Perumal,P. T. ?L 38, 5025(1997). roNishigaichi, Y., Hanano,Y., Takuwa,A. CL 33 (1998). rrMiyai,T., Inoue,K., Yasuda, I., Baba,A' TL39, 1929(1998)M., Shibata,

Indium(III) fluoride. Chemoselectiveformation of cyanohydrins from aldehydesin Cyanohydrtnafion.t the presenceof ketones is achieved in water using MerSiCN as donor and 30 mol% of InF,

Iodine. IodohYdrins a Iodohydrins. Cu(OAc), in dioxane.l Iodohl'drn opening of epoxides with iodine t provides iodohydrins.2 (Note iodu opposite direction.3) Protection and deProtcctbn ol O-acetylation of alcoholsaand ra: Trityl ethers are cleaved bY IJ}

not affected.6Discrimination of arl l (alkyl TBS ethers are selectivell. h1 such amides by brief treatment *id

Thioacetals are converted to cat In the PreParm Iodinatinns.

added.lo Iodination of aromatic | ll 1-(tosyloxy)-1,2-benziodoxol-3( iodination of 3,4-bis(trimethylsill I I

a combination of iodine and srlr unsymmetrical 3,4-diarylthiophcrrc a-Methoxy - o,ft unsaturatcd a ( I -methoxyalkylidene)+ungstent0 t the unsaturatedesters.When iodrr low.

W(CO)R ' ll \ V ,a\ V ,/\ OMe

LDA THF

as catalyst. rl-oh.T.-p.,Xu, K.-c., Ho, D. S.-c.,Sim,K.-Y. sL 369(1998).

Indium(IID iodide. Indium(Ilf iodide is preparedin situ from indium metal slices Transesterificatian.t and iodine in dry isopropanol at ambient temperaturefor 0.5 h. Methyl estersare converted to isopropyl estersby the solution. iodide catalyzes allylation of carbonyl Indium(Il! Homoallyl abohols.z compounds by allylstannanes. rRanu,B. C., Dutta,P., Sarkar,A. JOC 63,6027(1998). 2Miyai,T., Inoue,K., Yasuda,M., Baba,A. 5L 699(199'7)

Fornuti Heterocyclization' allylaminer6requires iodine and Nr N-acylcarbamates.lTA route to {-

of homopropargylic sulfonamidcs

lsanseverino, A. M., deManos.M. C 2Sharghi, H., Massah,A. R., Eshgh,.H 'Iranpoor,N., Tamami,8., Niknam-K aBorah.R., Deka,N., Sarma.J. C. ./CX sKulitu.D. J.,Borah,R., Sarma.J. C i

\iluhlrtro*. J. L., Ronald,R. C../OCr Tlipshutz,B. H., Keith,L TL39.2193 oMadsen, R.. Roberts,C., Fraser-Rcd

pcn:rdienyltributylstannane with n rr,,motedby InClr. Otherregio-

Iodine. Iodohydrins arc formed in a reaction of alkenes with iodine and Iodohydrins. Cu(OAc), in dioxane.l Iodohydrins are useful precursors of epoxides. Alternatively, opening of epoxides with iodine in dichloromethane in the presence of a crown ether provides iodohydrins.2 (Note iodine catalyzes opening of epoxides by alcohols in the opposite direction.3) Iodine has catalytic activities in Protection and ileprotection offunctional groups. O-acetylation of alcoholsaand acetalizationof carbonyl compounds.5 Trityl ethers are cleaved by IrlIvIeOH when other protecting groups (e.g., acetates)are not affected.6Discrimination of aryl and alkyl silyl ethersTis possibleby the sametreatment (alkyl TBS ethersare selectively hydrolyzed). The N-(4-pentenoyl) group is removed from

- = Bn

76"k

a = TBS

78"/o

6';

'.r hen InCl,

\::

rr.'.. and alkyl halides.

is reduced

with

such amides by brief treatment with iodine in aqueousTHF'8 Thioacetals are converted to carbonyl compounds by the lr-AgNO, couple.e In the preparation of o-iodoenones a catalytic amount of an amine is Iodinations. of aromatic rings with iodine activation by nitrogen dioxide,rl Iodination added.lo or mercury(I) oxidel3is effective.Desilylative 1-(tosyloxy)-1,2-benziodoxol-3(ll{;-one,r2 iodination of 3,4-bis(trimethylsilyl)thiophene can be carried out in a stepwisemanner using a combination of iodine and silver trifluoroacetate, thus permitting the synthesis of unsymmetrical 3,4-diarylthiophenesby coupling methods (e.g., Suzuki coupling).la a-Methoxy-a,ftunsaturated esters.tt Consecutive treatment of pentacarbonyl (1-methoxyalkylidene)-tungsten(0)with LDA, methanol, and iodine-triethylamine leads to the unsaturatedesters.When iodine is addedbefore MeOH the yields of the estersare very

9. 9^< 1997) L.*'

low. t

.:, 1998)

w(co)s

\ ,v^ . A v. .: - \.rnohydrinsfrom aldehYdesin Sr( \ .rr donor and 30 mo17oof InF,

*i

Liw(co)s MeoH;

|

W\oMs

+

12- Et3N

\ vn

tootvte v

-

bue

7O"/" Heterocyclization. Formation of N-tosyl-2-iodomethylaziridine from N-tosylallylaminer6requiresiodine and NaH, whereasIr-LiAl(OBut)o mediatescyclization of allyl N-acylcarbamates.lTA route to 4-iodo-2,3-dihydropynoles by iodine-induced cyclization r8 of homopropargylic sulfonamides involves a 5-endo-dig cyclization.

I

u:.: rn .itu from indium metal slices cr ' : h. Methyl estersare converted tlf,.!1!'\

oMe

LDA

allylation

of

carbonyl

rSanseverino, A. M., deMattos,M. C. S. sC 28,559(1998). 2sharghi, A. R.,Eshghi,H., Niknam,K. JOC 63,1455(1998). H., Massah, 'Iranpoor,N., Tamami,B., Niknam,K. CJC75, l9l3 (1997). "Borah,R.,Deka,N., Sarma, J. C. JCR(S)110(1997). 5Kulitu,D. J.,Borah,R.,Sarma, J. C. TL39,4573(1998). owahlstrom, J. L., Ronald,R. C. JOC 63,6021(1998). Tlipshutz,B. H., Keith,J. TL39,2495(1998). oMadsen, B. JOC 60,'1920(1995). R., Roberts,C., Fraser-Reid,

20O lodine0)ciloride eNi.hid",K., Nakamura,D., Yokota,K., Sumiya,T., Node,M., Ueda,M., Fuji, K. H,|4, 393(1997). P.,McNelis,E.5C27,Z;97(1997). E.,Bovonsombat, lfOiuarOi, "Noda, Y., Kashima,M. fl, 3E,6225(199'7). r2Muraki,T., Togo,H., Yokoyama,M. SZ286(1998). l3O.ito,K., Hatakeyama, T., Takeo,M., Suginome,H., Tokuda,M. s 23 (1997). toYe,x.-S., Wong,H. N. C. JoC 62,l94O(199'7). "Iwasawa,N., Fuchibe,K. CL 1149(1998). tuKitugu*u,O., Suzuki,T., Taguchi,T. JOC 63, 4842(1998). "Fujita, M., Kitagawa,O., Suzuki,T., Taguchi,T. JOC 62,7330(1997). ttK-r,ight,D. W., Redfem,A. L., Gilmore,J. CC 2207(1997).

Iodosylbenzene.13, 151; 16' 186; lE' lll: actrl ketene Silyl Oxidatians. on treatrrnl esters G-methoxycarboxylic obtained from the corresponding hydro (salen)Mn(Ilf complex, using PhI=O as ou hocedural variations of the oxidation of

containing a quatemary ammonium salt.i : former reaction gives sulfoxides, the laner c

RT

Iodine(I) bromide. Glycosyl bromides.r Glycosyl sulfides are converted to the bromides by IBr. When DABCO and MeOH are also added, methyl glycosides are obtained. 2,3-Alkadienoic estersare induced by IBr to give the lactones. ftIodobutenolides.t

RSBN

PT MesPh

rKartha,K. P. R.,Field,R. A.TL3E,8233(199'7). 2Marshall, J. A., Wolf, M. A., Wallace,E.M. JOC62,367(1997).

1,2-Diiodoalkenes.t Formation of either (E)- or (Z)-diiodoalkenes is possible using iodine chloride as source of iodine.

tct - Et4Nl

lOl - Nal

_ P h

cHzcl2 -7go

Ph

Ho.

a-Allylation.s Silyl enol ethersrer (PhI=O,Me,SiOTf).Thus,monoallylation

Iodine(I) chloride.

'\-/'

fto .

A

cH2ct2 o-250

|

I Ph

86"/"

tMoriu.ty,R. M., Rani,N., Condeiu,C', Dur-a. 2lee,N. H., Lee,C.-S.,Jung,D.-S.?t 39. l-1ES ' 3Tohrnu. H.. Kita-l H.. Takizawa,S.,Watanabe, asoh-iyu, H., Kimura,T., Fujita,M., Ando.T I 5Moriu.ty,R. M., Epa,W. R., Prakash, O. -rCRl

Iodosylbenzene-trimethylsilyl azide. 19. N,N-Dimethylarylamtt Azidonation. N-methyl derivativesl. When a Grignard n the amines results.2

undergo cyclization to (1H)-2-Benzothiopyrans,' 1,2-Bis(benzylthio)acetylenes give thenovelthiacycliccompounds.

MeO

Bn-S\

lCl / MeOH

'S-Bn

CHCI3 -7Oo

86o/"

rHenaff,N., Stewart, S. K., Whiting,A.TL38,4525(199'7). tKl.in, T. R., Bergemann, JOC 63,4626(1995). M., Yehia,N. A. M., Fanghanel,E.

Enones.2 Regioselective conversk accomplishedwith this reagentcombinatio

Iodosylbenzene-trimethylsilyl azide

r- \l . Fuji,K. H 4,393 (199'l).

':r 1997).

Iodosylbenzene.13, 15I ; 16, I 86; 18' 194; 19, 178 give to methoxylation acetals undergo ketene silyl ofidations. are ketones Aryl methanol'r in with PhI=O 0-methoxycarboxylic esters on treatrnent a by catalyzed oxidation an in obtained from the corresponding hydrocarbons (salen)Mn(Ilt) complex.using PhI=O as oxidant.2 procedural variations of the oxidation of sulfides with PhI=O include micellar medium containing a quaternary ammonium salt,3 and dispersion on a solid support.4While the former reaction gives sulfoxides, the latter can lead to c-S bond cleavage.

RSO2CI

RSBn

o rhe bromides by IBr. When llned. d f,r IBr to give the lactones.

HCt, sio2 Phl=O

MeSPh

MeSO2Ph HCI, sio2

Silyl enol ethers react with allylsilanes under oxidizing conditions a-Allylation.s (PhI=O, Me,SiOTf). Thus, monoallylation of ketones is achieved' i.rj,.alkenesis possibleusing

I

Nal

>H2ct2 ,-2sr

|

Ph 86"/"

rMoria.ty,R. M., Rani,N., Condeiu,C., Duncan,M. P.' Prakash,O' SC27' 32'13(199'7)' 2L"", N. H., Ire, C.-S.,Jung,D.-S.?L 39' 1385(1998). 3Tohrnu. H., Kita, Y. TL39'4547 (1998)' H., Takizawa,S.,Watanabe, asohlniya,H., Kimura,T., Fujita,M., Ando,T. T 54' 13'73'7 (1998). 5Mo.iu.ty,R. M., Epa,W. R., hakash,O' JCR(S)262(1991)' Iodosylbenzene-trimethylsilyl azide. 19' I 78 N,N-Dimethylarylamines are converted to the N-azidomethylAzidonation. N-methyl derivativesr. When a Grignard reagent is also present o-alkylation(arylation) of the amines results.2

ne*o/o LN.

/

75o/"

\-/-t-rn

Regioselective conversion of silyl enol ethers to enones is readilY

accomplishedwith this reagentcombination'

Iodotris(triphenylphosphine)rhodium(I)

o tl

OTIPS

2-('rn

Phl=O - Me3SiN3

ri^)

#

(,

CH2Clz

Ph

H-SiR3

\-,

50

73"/" (Ph3P)3RhCl tMagnm, P., Lacour, J., Weber, W. S 547 (1998). 2Mugnu., P., Lacour, J., Evans, P. A., Rigollier, P., Tobler, H. JACS 120,12486 (1998).

rMori,

(Z)-4-lodo-l-(tributylstannyl)but-l-ene. The reagent BurSnCH=CHCH'CH2I acts as electrophile to 2'Cyclohexenols.t attach a four-carbon unit to a ketone. Subsequently undergoing Sn/Li exchange and intramolecular attack on the ketone results in a cyclohexenol which can be oxidized to

A., Takahisa, 8., Kajiro, H.' Hiraberr

Iridium. Reduction.t Aromaticnitro groq catalyst.Nitrateestersareretained.

furnish a (transposed)cyclohexenone.

Bu35n._ NNMe2 |

+

.Y | \2"

|

-=

o/\o t l

X

-"# 2\

x" !

92"/"

rPiers,8., Boulet,S.L. SI 516(1998).

Iodotrifluoromethane. a-Iodoketones.r Iodotrifluoromethane is a useful iodine donor to react with enolates.

'Fedorov.

B. S.. Dorokhov, V. G., Arakctpr

Iron.19. 179-180 Carbon radi Radicalgeneration' heated with iron.r-3 These radicals can and l.l 1,1-difluoro-1,3-diiodoalkanes

difluorodiiodomethane with electron-r under such conditions.3 Note that zirrc

electron-rich alkenes. Intramolecular cyclization of \-e derivativesais promoted with Fe-Fdl. r

tEnde.r,D., Klein,D., Raabe, G.,Runsink,L SL l27l (1997).

Bn I

Iodotris(triphenylphosphine)rhodium(I). This catalyst or (P\P),RhCl-NaI Alkenylsilanes.t

catalyzes the hydrosilylation of 1-alkynes. When the catalyst is premixed with the hydrosiloxane reagentsthe products are predominantly (Z). On the other hand, on successive addition of the alkynes and the hydrosiloxanes to the catalyst, only (E)-alkenylsiloxanes are obtained.

Z\r*)=o / -1-c' cl

Fe.j

Orf

Iron

203

- Nal (Ph3P)3RhCl

o -'fpn I

R3Si

P

(premixing with Rh catalyst)

H-SiR3 RaSi

73o/o

\

(Ph3P)3Rhcl

rMo.i,A.,Takahisa, Y', Hiyama'T' CL443(1998)' K'' Nishihara, E.,Kajiro,H.,Hirabayashi'

(1998). Lr, . 120.12486

lll ( t{.1 acts as electroPhile to u:.iir'rgoing Sn/Li exchange and F\.n()l which can be oxidized to

Iridium. usingIrlC as Reduction.r Aromaticnitro groupsarereducedduringhydrogenation catalyst.Nitrateestersareretained.

9

":S^ \ e.- r l l

Ph

"# z\

X !

c:.- rodine donor to react with

Hz ' trtc,

ozru{ /Y, HN--\

tr*\_/]*__^

HoAc

\_OruOz

LONO2

rF"dorou, MC 173(1997)' V. G., Arakcheeva,Y.Y. B. S.,Dorokhov,

Iron.19, 179-180 carbon radicals are formed when polyhalogen compounds are Radicalgeneration. a route to heated with iron.r-3 These radicals can be intercepted by alkenes, for example, of reaction 1,l-difluoro-I,3-diiodoalkanes and 1,1-difluoro-l-iodoalkanesinvolves the respectively, difluorodiiodomethane with electron-rich and electron-deficient alkenes, reaction of under such conditions.3 Note that zinc can replace iron powder only in the electron-rich alkenes. Intramolecular cyclization of N-allyl-2,2-dihaloamides to afford 2-pyrrolidinone derivativesais promoted with Fe-FeCl, in DMF.

Bn

Bn

I

I

'A"'N;6 i:l ..rtalyzesthe hydrosilylationof r\.:., \rne reagentsthe Productsare e :iJrtion of the alkYnes and the :s ::. r)btained.

F

Fe - FeCl3

/ -1-.'

DMF

8OO

1*)=o \

/

o-,u,rlct

cl 95o/o (trans: ctis 20 :80)

Iron(III) chloride

tForti, L., Ghelfi, F., Libertini, E., Pagnoni, U. M., Soragni, E. T 53, 17761 (1997). 2Bellesia, F., Forti, L., Ghelfi, F., Pagnoni, U. M. SC 27, 96l (lgg7). 3Li, A.-R., Chen, Q.-Y. JFC 8l,ggl (1997). "Benedetti, M., Forti, L., Ghelfi, F., Pagnoni, U. M., Ronzoni, R. T 53, 14031 (199'7).

Aminesfrom azides.s Reduction requiresFeCl.asc N,N-dimethylhydrazine

Ho\Z-v l

Iron(II) chloride. Reactianofisoxazoles.t Iron(II) chlorideis capableof isomerizingisoxazolesto estersor effectingring cleavageto enaminoketones. azirenecarboxylic

OMe

I A\ I phrl--N'

FeCl2 O

*cozMe

+ MecN

t qxo l

l

\

""or'*-*fl \'/ I

l

a

,

1,3-Dicarbonll Michael reactions. form with catalysis of iron(IID chlori& h 46-1007a).6 An intramolecular version r 7-membered ring.?

Ph/:N >V5-/o

Ph

Ph

/" t o PhA-N'

MeCN

R

Ao ll

FeCl2 Ph

o

NH2

E = COOMe 58%

Nitrene transfer.2 t-Butoxycarbonyl azide loses dinitrogen and delivers the N-Boc residue to sulfur compounds (sulfides, sulfoxides) and ketene acetals. lAuricchio,S.,Bini, A., Pastormerlo,8., A. M. f 53, 10911(1997). Truscello, 2Bach, T., Korber,C. fL 39,5015(1998). Iron(IID chloride. 13, 133-134;14,164-165;15, 158-159; 16,167 -169, 190-19l; 17, 1 3 8 - 1 3 9 ;1 8 , 1 9 7 ;1 9 , I 8 0 - 1 8 1 t Diazo compounds are formed. Dehydrogenation of carbazides.

rwang,Y., Shi,L., Jia,X. SC28, 2281(l99El 'Sen,S.E.,Roach,S.L., Bogg,J. K., E*'ing.G 3sul"hi,P.,Iranpoor,N., Behbahani, F. K. f 5{ "Yang,H., Li, B. C. Y. SC28,1233(1998). sKamal,A., Reddy,B. S. N. CZ 593(1998). 6Christoffers, J. JCS(Pl) 3141(lgg7). Tchristoffers, J. z 39, 7083(198).

Iron(IID 2-ethylhexanoate. Hetero Diels-Alder reactions.t'Ilr catalyst. Thus, cis-2,4-disubstituteddihl'd

H H P h . , N N 'N' P h N V i l H H

FeCl3 2N H2SO4

tn'ni'*

N.. ,Ph N

Y o

81'/" Protection and deprotection offunctional groups. Deacetylation2as well as allylic ether formation3 are readily performed with iron(Il! chloride as catalyst. Acetylation and esterificationcan utilize a catalyst which is supportedon a salicylic acid resini

tco.-un. D. B., Tomlinson, I. A. CC 25 rl99-r

Iron(IID nitrate. Oxidatians,

Sulfides iue conven

combination of iron(IID nitrate and silE effects oxidation of benzylic alcohols to d l-Tn Bitycla[3.3.0]octan-3-ones,o verted to the bicyclo[3.3.0]octanone b1

--61 (1997).

Ll a

t s-r .t031 (1997).

Iron(Itr) nitrate

ns

amines to azides various of Amines from azides.s Reduction N,N-dimethylhydrazine requires FeCl, as catalyst. Nitro groups are not reduced'

by

*o:Zy*. I

t-

lc ,,t isomerizing lsoxazoles to

-COeMe h

ll

Me2NNH2

\

tl

Meo"\"">-(

I

un,' ketones.

*fi(*-lA

qno

-; -\

M"o.\}NJ

1,3-Dicarbonyl compoundsreact with Michael acceptorsin neat Michael reactions. form with catalysis of iron(III) chloride hexahydrate at room temperature (19 examples' 46-lOO7o).6An intramolecular version is also quite rewarding for the formation of a 7-membered ring.7

/-N ,35.o Ph

'\^

-

FeCl3 U

CH2Cl2

A"t, E = COOMe : 3'"

nr::,'!en and delivers theN-Boc cl'.araetals. t-* . . 1997).

rWang,Y., Shi,L., Jia,X. SC2E,2287(1998). 2Sen,S. E., Roach,S. L., Bogg,J. K., Ewing,G. J.,Magrath'J. JOC 62' 6684(1997)' 3sul"hi,P.,Iranpoor,N., Behbahani, F. K. 254, 943(1997). aYang,H., Li, B. C. Y. SC28, 1233(1993). 5Kamal,A., Reddy,B. S.N. CI 593(1998). ochristoffers. J. JCS(PI ) 3 l4l (1997). Tchristoffers. J. TL 39,7083(1998).

5" 16.167-169,190-191;17, l. ::c' tbrmed.

Iron(IID 2-ethylhexanoate. Hetero Dicls-Alder reactinns.'

The iron carboxylate is a mild and highly selective catalyst. Thus, crs-2,4-disubstituteddihydropyranyl ethers are readily obtained.

o't"Yto'tn

'Go.man.D. B., Tomlinson,l.A. CC 25 (199'l).

o 81'/" as well as allylic I).',rcetylation2 x:i': ar catalyst. AcetYlation and I .r: rcrlic acidresini

Iron(IID nitrate. Ofidations.

Sulfides are converted to sulfoxides, thiols to disulfides,l while a combination of iron(IID nitrate and silica gel cleaves 1,3-dithianes.2The same reagent effectsoxidation of benzylicalcoholsto aldehydes.l Bicyclo[3.3.0]octan-3-ones.a l-Trimethylsiloxybicyclo[5.1.0]oct-2-ene is converted to the bicyclo[3.3.0]octanone by iron(Il!

nitrate (1,4-cyclohexadiene added as

206

Iron pentacarbonyl

hydrogen donor). From substratescontaining a 3-(alk-3-enyl) substituentfurther cyclization to the angular triquinane system is possible, when the hydrogen donor is omitted.

Ph

ill I

Fe(CO)s EtMgBr- CuO

Ph

-ffi.P,r A"'"\:vl*rl DMF L(2 ] Y Y rFirouzabadi, H., Iranpoor, N., Zolfigol,M. A. SC28, 1179(1998). 'Hirano,M., Ukawaq,K., Yakabe,S.,Morimoto,T. SC27, 152'7(1997). 3Khudilk., B., Borkar,S. sC2E, 207(lgg9). aBooker-Milburn, K. I., Dainty,R. F. 7L 39,5097(1998).

THF,MeCN

rCrivello,J. V., Kong,S. JOC 63,6745( l9S 'Dolham, E., Ocafrain,M., Nedelec,J. Y.. Tn 3Rudhukirhnun, Periasamy, U., M. OM 16.ll

Iron(III) perchlorate. C-C bond formations.t lront III r 1,5-cyclooctadienesto bicyclo[3.3.0]c naphthalenes.Thiols are also oxidized to

() Iron(IID nitrate-dinitrogen tetroxide. Phenols undergo selectivemono and dinitration. Nitration.t Oxidation of alcohols2 and their trimethylsilyl ethers3 at room Oxidations. temperatureaffords carbonyl products. Copper(Il) nitrate*dinitrogen tetroxide can also be

Fe(oo.b M€cil

\_/-r'

used. rFirouzabadi, N., Zolfigol,M. A. SC27,3301(1997). H., Iranpoor, 'Iranpoor,N., Firouzabadi, H., Zolfigol,M. A. BCSJ71,905(1998). rFirouzabadi, H., Iranpoor,N., Zolfigol, M. A. BCS,I71,2169(1998).

oxide-oxygen-aldehyde. This system is capable of effecting epoxidationr and conversion of Oxidations, sulfides to sulfoxides.2

Esterificatian. Iron(IIf perchlrr acidsto esters(28 examples,55-88%).: I

lKu.ar, B., Parmar,A., Rajpal,A., Kumar. H 'Parmar,A., Kaur, J.,Goyal,R., Kumar.B.. X 'Zhang, G.-S.sC 28, I 159(1998).

Iron(IIf

rl-i, X., Wang,F.,Lu, X., Song,G., Zhang,H.SC27,20'75(1997). 'Song, Wang,F., Zhang,H.,Lu, X., Wang,C. SC2E,2'183(1998). G.,

Iron pentacarbonyl. 13, 152; 18, 196 Allyl ethers are converted to an (E/Q-mixture of enol ethers. Isomerizatinns.t Ketones.2 An electrochemical method for ketone synthesis which produces RCOR from RX is mediated by Fe(CO)r"and(bpy)NiBrr. An alkyne, a Grignard reagent, and Fe(CO)t Three-component coupling.' contribute to the skeletal elements of butenolide which is formed in the presenceof CuCl, albeit in low yields. Cyclobutenedione is another product which is formed without participation of the Grignard reagent.

L-(Isocyanomethoxy)benzotriazole.

Oxazoles.t Oxazoles are formed aldehydesand acid chlorides. The isoniu by dehydration with POC\-EIrN.

N

)ruF N 6J

N

'Sasaki,H. CPB 45, 1369(199'7).

1-(Isocyanomethoxy)benzotriazole

r\ . . rbstituent further cyclization hi'{3n donor is omitted.

Ph

ill I Ph

o

^A' 1/ -J s s

Fe(CO)s , EtMgBr- CuCl

Ph

'nJ,-ro

Ph

pnAo

THF,MeCN 13Yo

267o

o

^' ( fl"'/

297

l l

lCrivello,J. V., Kong,S..rOC63,6745(1998). 2Dolhurn.E.. Ocafrain,M., Nedelec,J. Y., Troupel,M. T 53, 17089(199"1)' 'Rudhukirhn-, U., Periasamy, M. OM 16,1800(1997).

c"" Iron(IID perchlorate. of cyclization effects perchlorate Iron(IID C-C bondformations.l l,5-cyclooctadienes to bicyclo[3.3.0]octane derivatives and oxidative dimerization of naphthalenes.Thiols are also oxidized to give disulfides.

C\ b:'.:::,rttttn. ::rrrcthylsilyl ethers3 at room c - j::r rtrogentetroxidecan also be

\_r''

l*'

| :r,ridationl and conversionof

MeCN

70/" Esterification.

9F.

Fe(Cl04)3

Iron(III) perchlorate adsorbed in silica gel effects transformation of

acidstoesters(28examples,55-88Vo)?Iron(III)sulfatecanalsobeusedfortrispuropse'l rKumur,8., Parmar,A., Rajpal,A., Kumar,H- IJC 3TB'593(1998). 2Pur.-, A., Kaur,J.,Goyal,R., Kumar,B', Kumar,H. SC28' 2821(1998)' 3zhang,G.-S.sC 2E,I 159(1993).

1-(Isocyanomethoxy)benzotriazole. Oxazoles.t Oxazoles are formed using this building block on reaction with aldehydesand acid chlorides. The isonitrile is preparedfrom the corresponding formamide by dehydration with POCI-EIrN.

N rl ,2,-mixtureof enol ethers. : .'.:'.:hcsiswhich ProducesRCOR lr::nrrd reagent, and Fe(CO)t i: :,,nned in the Presenceof CuCl' n'.-rr.t which is formed without

) r uN F N 5J rSasaki,H. CPB 45, 1369(1997).

t-BuOK'THF +

PhCHO

*I)

Lanthanum(Ill) trifl uoromsthrrq Cyclizntion.t Chelationeffcc ether.

Lanthanum(Ill) chloride. 18,201 Esterification.r Selectiveacetylationof primary alcohols occurs with methyl asreagentandLaClr/SiO2ascatalyst. orthoacetate

MeO-. ,4

u

La(orf)3

\

;il

ro)

AcO LaCl3 / SiO2

HO,,',

MeC(OMe)3

'Fujiwara,

K., Mishima, H., Amano..{ .l

92% Hydrodehalogenation.2

Aryl halides are reducedby nanometric NaH using LaCl, as

catalyst. 'Biun"o,A., Brufani,M., Melchioni,C.,Romagnoli, P. TL38,651(1997). 'Zhang,Y., Liao,S.,Xu, Y., Yu, D., Shen, SC27,4327(1997). Q.

Lanthanum(Ill) tris(hexamethyld Tishchenkoreaction.t Vanq esters. rBerberich, P.W.ACIEEn. H.,Roesky,

Lanthanum(IlD

iodide. The acyl group of such a derivative is reAlcoholysis of N-acyloxazolidinones.t moved with an alcohol in the presenceof LiI,.

Lead.19, 184 Oxazolidin-4-ones.' Difluqo with leadpowder.Tr fluoromethane ylideswhich,in thepresence of aldc

tFukuru*u, Hongo,Y. TL39,3521(1993). S.,

Lanthanum(Ill) isopropoxide. 17, 160; 18, 201; L9, 184 Self-condensationofaldehydes as well as Robinson annulation are Aldol reactions.t effected. The latter processis conducted in the presenceof molecular sieves 44 in aprotic solventssuch as toluene.

Ph

I

r^" Ph2'

P b - 8 +

PhCHO

*d ot

Ph

*

l

I

(i-PeO)3La

--rAo

MS.4A

\

PhMe

.) en/\\o 85%

lokano,T., Satou,Y., Tamura, M., KUi,J BCSI70, I 879(1998). 208

Bn

I -N (' Ph

rNovikov,

M. S., Khlebnikov, A. F.. Krtl

Lead(IV)acetate.13,155-156:l{ 6-Lactones. Oxidativecycl with Pb(OAc)oresultsin destannlb areobtainedwhenalkanolsundergo

Lead0v)acetste

2W

Lanthanum(IlD trifluoromethanesulfonate. cyclic cyclizntion.r Chelationeffect directsthe formationof an eight-membered ether.

n

.rliohols occurs with methYl

"*;O

HOJ

""o{3'n La(orrb ';

'

,,.,,,( '6-J

MeCN

)

Meo\"'\/\ 6.t---/

(98 : 2) A:l -1 \/

-:

\ iO

71"k

al .-r,

,),',,orvte

/-r..

tFuli*u.u, T.,Murai,A. TL39'393(1998)' A.,Tokiwano, H.,Amano, K.,Mishima,

OH 92n"

NaH using LaCl, as I i': :r.rnometric

A
99:l\.4

LTMP/THF OO t

PhCHO 70"/o

OBn

such as that IntramolecularC-acylation' Treatmentof 4-acyl-l'3-dioxan-2-ones of contraction in ring for taxol synthesidwith LTMP results appearingas an intermediate the heterocycle.

I

a(

Lithium tri-s-butylborohydride (L-Selectride)

TESO-.

P , ::.-.o. P. A., Strauss,S' H' OM 15'

."--\z

:.'--\z o

l7 , 171-1'72; . . " l.l. 194-195:, ;r:- chlorides (bY reaction with icJ.:r(\nof the ring-expandedspecies b Siereodefined llithio-l-chlororti .,.rr lzirconocenesto afford @- or

TBSO'"'

LTMP

o{ 6 - ' o 90% 'Gordon,G. J.,Whitby,R. J. CC 1045(1997). 2Kasatkin, A., Whitby,R. J. rL 38, 485'7(1997). 3Mutrurnoto, Y., Suzuki,K. TL38,8985(1997). T., Kuriyama, T., Hamura, oHolton,R. A., Somoza, P. D., Shindo,M.' Smith' R. J.,Boatman' C., Kim, H.-B.,Liang,F.,Biediger, H., Suzuki,Y., Tao,C.,Vu, P.,Tang,S.,Zhang,P.,Murthi'K. K., Gentile' C. C.,Kim, S.,Nadizadeh, L. N.. Liu. J. H. JACS116.159'7(1994).

Lithium tri-s-butylborohydride (L-Selectride). 19, 202-203 Aryl methyl ethers are cleaved with L-Selectride in refluxing De-O-methylation. THF.I By this method removal of the protecting group from methyl carbamatesis possible in the presenceof r-butyl carbamates.2

ph

-,,\6=

L-Selectride .,.#

THF

(86 : 1a) 797"

A

OMe

MeO

237o

t\',

'n of an aromatic aldehYdeunit '.c l-arylisochroman-3-ones is

L-Selectride

I-BuOOC-N

N-COOMe

I-BuOOC-N

THF

NH

25O

87% syn-1,2-Amino alcohols are obtained by l,2-Diols and l,2-amino alcohols. Interestingly,O-benzyloxy ketonesgive ketones.3 L-Selectridereduction ofa-dibenzylamino (e.g., anti:syn =6:1) which can be ratios with low isomer anti-1,2-diol monobenzyl ethers to lithium tri*-butylborohydride agent the reducing increased dramatically by changing (>99:I ).4 701o

OBn

OBn

such as that 4-,, r.- 1.3-dioxan-2-ones of contraction ring in results T\tP i iLts

I /\/

Li(n-BusBH)

...................* tl

o

Et2O- pentane CH2CI2 -7Bo

^/ 6H > 70'/"

22E

Lithiumtriethylborohydride

1Coop, A., Lewis, J. W., Rice, K. C. JOC 61,6774 (1996). 'Coop, A., Rice, K. C. TL39,8933 (1998). 3chung, S.-K., Kang, D.-H.TA8,302"1 (1997). 4Faucher, A.-M., Brochu, C., Landry, S. R., Duchesne,I., Hantos,S., Roy' A., Myles, A., Legault, C. rL39,8425 (1998).

Lithium triethylborohydride. ftHydroxy sulfones.t The reductionof a-sulfonyl ketonesproceedsby different steric courses when exposed to LiBEt3H-CeCl, and to BHr/pyridine-TiClo' The anti-isomerdominatesin the former reaction.

o tl

So2Ph

-tto ,

9*so2Ph

SO2Ph +

I

I - CeCl3 85'/" LiBEt3H

U.COOMe

I ll \./

*

z\^..c| /o\cr

M g - 1 2 /N M P ; aq. NH4CI 570k

[6+4]Cyctoadditions.t5 The Cr(0)-mediated cycloaddition reaction is rendered catalytic in chromium by adding Mg powder to maintain it in the proper oxidation state.

__/-\_

Hydride transfer.6 Aromarizarx transferto unsaturated substrates in rhc

Np-C(Co)3 ....."...+

BuCN Mg 14Oo rHolzapfel, C. W., Portwig, M. H 45, 1433(lgg'1). "Sridhar, M., Kumar, B. A., Narender, R. fL 39, 2847 (1998). 3Nyurr", B., Grehn,L., Ragnarsson, U. CC I0l7 (lggl). -Grehn, L., Nyasse,B., Ragnarsson,U. S 1429(1997). 'Alonso, D. A., Andersson.P.G. JOC 63.9455 (1998). 6puk, c. S., Kim, T. H., Ha, s. J. ,/oc 63. 10006il998). tM"ll"n., J . M . , S c h o f i e l dS , . R . , K o r n ,S . R . 7 5 3 , l 7 l 5 l ( l g g : ) . oHo, T . - L . , L e e , K . - Y . , C h e n ,C . - K . J O C 6 2 , 3 3 6 5( 1 9 9 7 ) . "Shen, Y., Qi, M. SC 27, 43lg (lgg7). "'Hu, H., Song,Y.-L., Fang,Y., Zhou, C.-8., Tao, F.-G., Cti, J. yH 17, 4i8 (lgg7). "Zhang, w . - C . , L i , C . - J .J C S ( P t ) 3 l 3 l ( 1 9 9 8 ) . '-Touster,J., Fry,A. J.TL38,6553 (1997). ''Tongco, E . C . , W a n g ,Q . , P r a k a s hG , . K. S. SC27, 2tl7 (1997). '*Tongco, E . C . , W a n g ,Q . , P r a k a s hG , . K. S. S l08l (1997). ''Rigby, J. H., FiedlerC , . H . J O C 6 2 , 6 1 0 6( 1 9 9 7 ) .

Magnesium bromide. 15, 194 - 196; 16, 199; 17, 1'14 ; 18, 226-227 ; 19, 206-20j Deprotection.' p-Methoxybenzyl ethers suffer cleavage on treatment with MgBrr.OEt, and MerS at room temperature.Benzyl ethers survive such conditions. Acetonides and trityl ethers are deblocked with MgBr, in refluxing benzene.2The facile regeneration of carboxylic acids from their B-(trimethylsilyl)ethoxymethyl esters without affecting Boc, Cbz, Fmoc, and Troc carbamatesmakes them useful in peptide synthesis.3 Anomertzatian,a o-Glucosides are obtained from the B-anomers by treating with MgBrr.OEt, and a catalytic amount of Ti\. 3-Hydroxyazeti.dines.5 2,3-Epoxy amines undergo isomerization (cyclization). The reaction is stereoselective.

Imine aldol reaction. Efficienr o promoted by MgBrr-EtrN. Remarkabl; temperature, whereas at lower tcnT configuration.T

t .,,\I U

l RCHo/ MsBr2- e MECN

Chiral 2-bromoalkanols.s [li

ai'.

1 / -\J-'n f

skeletal with Cyclization Dihydrobenzofurans and 2,2-dimethylchromans. for in toluene, with Mo(CO)o are heated reaffangementis observed when aryl allyl ethers example, aryl prenyl ethers give 2,2-dimethylchromans'4'5

er"\

Mo(CO)e P h M e 11 0 o

Oxidation.b Oxidation of cyclohexene and norbornenewith Mo(CO)u-l-BuOOH in supercritical carbon dioxide gives vic-diols. Some alkenes (e.g., cyclooctene) afford epoxidesbut vinylnaphthalenesand cis-stilbeneundergo oxidative cleavageto the aromatic aldehydes. Cyclopentenones.l Allenynes undergo a Pauson-Khand-type reaction in the presenceof Mo(CO)u in DMSO. The substitution pattern of the allenyl moiety has profound

252

Montmorilloniteclays,metalion doped

effects on the product structures. Thus, monosubstituted allenes give Cr-methylene cyclopentenones,whereasdisubstitution alters the course.

q-''"* Mo(Co)o

+

SiMe3

fY\-o

Nafion-H. 14, 213:'lt, 246 Ep oxide cy clizntio tr-l formation.However,this t presence of Lewis acids.

DMSO - PhMe

\

1000

687o

(

B --\^

u

Mo(C0)6 + DMSO - PhMe

/--Zf l l '("

1ooo

\

F

2>/

o

U

Bu 607o

'Geneste, F., Racelma, N., Moradpour, A. SC 27,957 (199'l). 2shitnirr, I., Khien, K. M., Nagatomo,M., Nakajima,T., Yamamoto,A. CL 851 (1997). 3shi-iru, I., Sakamoto,T., Kawaragi, S., Maruyama, Y., Yamamoto, A. CL 137 (199'1)aBernard, A. M., Cocco, M. T., Onnis, V., Piras,P. P. S 41 (1997). sBernard, A. M., Cocco,M. T., Onnis,V., Piras,P. P. S 256 (1998). oHaas, G. R., Kolis, l.W . OM l7 , 4454(1998). 7Brummond, M., Wan, H., Kent, J.L. JOC 63,6535 (1998). K.

Montmorillonite clays. 15,213 -214: 18,244-245; 19,222 Montmorillonite clays,metal ion doped.15, l}l , 178-179;18,244-245;19,223 The effectsof clayson practiallyall typesof organicreactionshavebeeninvestigated.

&

rTaylor, S.K.,Dickinson. M, (

Nickel.12,355;13, 197:lt UIJmanncoupling.l electrolysis of a DMF solu current.aryl halidesunderg Reductianof nifivnnt catalystpreparedby reduco nitroarenes areconvertedlo Hydroindolaneform alkaloidsinvolvescyclizar acidin refluxingisopropao

Meo-lz)a t"o'^Vf(

FV

/

D

\--l

3-demefit

trlr..:rtuted allenes give ct-methylene xlLr.a

SiMe3

f-(Yo

Nafion-H. 14,213;18,246 with Nafion-Hleadsto ring Epoxidecyclimtian.t Treatmentof o-epoxyalkylarenes formation.However,this transformationdoesnot alwaysparallelthat conductedin the

\

of Lewis acids. Dresence

68%

a'^\z\ l l F

\N

o

CH2C|2 - CF3CH2OH

\n

I Bu

88"/o

60"h

F-

'\ '\

ara =,Y

r : . r m o t oA. . C L 8 5 1 ( 1 9 9 7 ) . 'r.1moto.A. CLl37 (199'7).

I q9N ).

t: le.ll2 1 . . r- I 79;18,244-245;19'223 r ! , . reactionshavebeeninvestigated

lTaylor,S.K., Dickinson, P' C' S 1133(1998)' D A', Sadek, M. G', May' S.A., Pickering,

Nickel. 12, 355 : 13, 197; 14, 213; 18, 246; 19, 224 Using the highly reactive nickel which is prepared by Ullmann coupling.t electrolysis of a DMF solution in an undivided cell (Pt cathode, Ni anode) at a constant current, aryl halides undergo coupling to give biaryls at 100" (4 examples, 58-90Vo). Reduction of nitroarenes.2 with hydrazine hydrate as hydrogen sourceand a nickel potassium. catalyst preparedby reduction of anhydrousNiCl, with ultrasonically dispersed nitroarenesare converted to arylamines at room temperature(9 examples' 90-lNVo). An expedient method for the synthesis of erythrina Hydroindolone formation,3 enamideswith nickel powder and acetic of N-trichloroacetyl alkaloids involves cyclization acid in refluxing isoproPanol.

rvreoffi

.o

""oy)fi.

o*"o

%*t"'

""o'Jr-s1"t-'' j"'*rY :*^".;; ,V Xt (r" Y l Ir MeO

3-demethoxyeMhratidinone

(,

254

Nickel, Raney

rYasuhara, A., Kasano, A., Sakamoto,T. OM l7 , 4754 (1998). tLi,H.,Zhung,R., Wang, H., Pan,Y., Shi, Y. SC 27, 304'7(lgg7). tcassayre, J., Quiclersire, B., Saunier,I.-F ., Zard, S. Z. TL 39, 8995 ( 199S).

Nickel, Raney. 13,265-266; 14,270; 15, 2'18;17,296; 18,246 Cleavageof hydrazines.t Hydrogenolysis follows addition of alkyllithiums to SAMP/RAMP hydrazonesin chiral amine synthesis(13 examples,4l-73%o). Isoquinolines.2 N-Benzylsulfonyl- 1,2-dihydroisoquinolines undergo aromatization heating on with Raney-Ni in dioxane(6 examples,6l-99%o).

Ra-Ni

MeO

NS02Bn

dioxane

MeO

A

7 5"/o

Hydrogenations.'

The Raney nickel-isopropanol system shows superiority over

Nickel accirr Desulltri N-methylpip (generally5dramaticin cr Aminab Ni(OAc),-2. lKuehm-Caubcr 2Brenner, E.. R

Nickel(U) r Crussr:a aryl chlorida divalentsulfu reagents.3 For exceedingll preparationo reactionwith

many others in catalytic hydrogenation. Epimerization.a The C-3 of digitoxosides undergo epimerization under hydrogenation conditions (Raney Ni, MeOH, 50') to afford olivosides (7 examples, 96-997o). With nascent Raney nickel generatedfrom Ni-Al alloy in Hydrodechlorination.s dilute aqueous alkaline solutions, chlorinated biaryls can be dechlorinated or have the chlorinated ring completely converted to a cyclohexane moiety.

(ffi''

w w

100%

Stille-ryp provides sqrr

For acccs catalyzed b} i Orgatu (particularll t

catalyzed by system effect Homoally 3-buten-I -1lt

100Yo tEnde.r, D., Nubling, C., Schubert,H., Bartzen,D. LA 1089(1997). 'Larghi, E. L., Kaufman,T. S. 7L 38, 3159 (1997). rRegla, I., Reyes,A., Korber, C., Demare,P., Estrada,O., Juaristi,E. SC 27,817 (1997). *Toshima, K.,Inagaki, K., Nakata,M., Matsumura,S. S4 695 (1997). 'Lin. G.-B., Tsukinoki, T., Kanada,T., Mitoma, Y., Tashiro,M. TL39,5991 (1998).

i

,

Nickel(Il)


25: 1'1

256

Nickelbromiile-phosphinecomplexes

to alkynes in the The addition of organometals Addition-coupling sequences' used to couple with allylic Itotnylmetals which canle presenceof Ni(acac)r ,"tJ** Cu (in casesof Zrit3 ' 1'4-Dienes Al)12 or after exchangewith halides directly (rn casesof are formed.

CouPtitq o

electrochemrcel halides in alcot

elecnochemica (bpY)"NiBr-.

tn..

* c':,A

( I

Ni(acac)z- THF +

Me3Al \

250

ireN -s

68%

rMiller,J. A., Fanell'R' P' ?L39' O+lt'72'15(lW' (1ee8)

Indanols deficientalla to substiuted

P rACs120'r 1186 Knocher' .^ (1998)' {;;;;iln., C.,rno"n.r,p' Ac.lEE37' 2387 3ciovannini, R.,stiio"*unn,f, Ju,*-ri"n, 1213^(1998)' ti", ".,'""' i-' "ang,S''wang'J'-X''Yin'Y' sL t^tnirJ"*"' e ' Yaniasaki' r''"iivama't' s ts++(1??9]'.' Oee'l')' til;;;,;, r'' uiiu'u' r' ICS(Pt)244e Yamasaki, P' IL,3& 1005(1997)' L'' Knochel' Tstiidemann' v" engrn'an' T.,Cupta' P sL 143(1998)' Knochel' sStiidemann, T.,Ibrahim-ouaf'*,'A"t' G',

' 5""rri:i :i;il;;;;; :.':li*i.$ illlllllT::iliill?33),

( \

lolchiyanagi. s T., KuniYama' 4033(1998)' "Kituru, M., Ezoe,e', stt'uaia'f'' Tamaru'Y' JACS120' ' oM 11' 4316(1ee8)' 'ti;;;;,; , Mivashita,H'' Sato'Y (Lee't)' 'til;;;;"'i., Knochel'P' ACIEE36'e3

Nickel boride-borohydride

1,+Au to a conjugl

exchange resin'

t: addition"l tnll eroury'fom y :t::t-deficient Cross-couplings'Conjugate resinin methanol exchange Uo:rofrydride anO tV " .",if',li "-""n "f mp isprom"OA esters'2 alkenes utttn"*-O ct-uromalkanoic 40-937o)'tetitf'"'"""ptLg inuoln"t (39examples'

o tl

Ni2B

a\-

\--r-

+

r-cooEt

B{

(/ \ \'r- /

r-COOEI

I

borohydrideexchangeresln MEOH

91"/"

(J99'l)' 'siln, T. B , Choi,J', Joung'M' J'' Yoon'N' M' JoC 62' 235'1 (d1.998)' 63'2'755 JOC M' N' Yoon' 2Joung, M. J.,Ahn,J' ff " "*' U W ' complexes' Nickel bromide-phosphine groups from an aromatlc removal of mesyloxy -+ArH't t;'';il;"t AroMs presenceof dppb' of @htP)'NiBr' in the nucleus with Zn-Kl t, ."t"ipJ

I

a

rSasaki.K-. I 2Kamekana3Courtois.v aDuran&nr. sGrigsbv. s 6Jou,D.-C..

257 Nickelbromide-phosphinecomplexes

(::.rn(rmetalsto alkynes in the ai \,' used to couple with allYlic r ( .. rn casesof Zn)r3. l,4-Dienes

Alkenyl bromides are homologated in an Coupling of alkenyU aryl halides. Biaryls are formed in an electroreductivecoupling of aryl carboxylation.2 electrochemical is observed in arylation by means of induction Asymmetric solvents.3 halides in alcoholic for all the above types of reactions is catalyst The electrochemical cross-coupling.4 (bpy)rNiBrr.

9

3

o

.\

ll

M"\' ,lu-v",

(bipy)NiClz +

Phl

BuaNBFa

I

'Ph

r'

M"\'

o

J '|l-\-pn t i l

\___J '1 a:

r

P

h

-i

DMF 57"/o QO"/" ael

Indanols.s o-Acylarylmanganese tetracarbonyl complexes react with electrondeficient alkenes in a tandem demetallative conjugate addition and aldol reaction, leading to substitutedindanols.

[.' .r- :]lt7 (1998). i

9ir. . q97). s. :r 1998) : :: 1998). ' :.r,i997) []:: a98).

(Ph3P)2NiB12

,\^"

\A"n,.o,o

MeCN

a

MVK 910/"

Two identical units derived from an organohalidecan be introduced

1,4-Additions.u rr .... tiom RI to elecfion-deficient r. :...lnde exchangeresin in methanol :r,r, .:nJ c.-bromalkanoicesters'2

to a conjugated diene.

tl 9€

l

'ts . 91"k

: "

998).

n-f.\l)\v groups from an aromatic t .:.\cnce ofdppb.

(Ph3P)2NiB12

l

l

+ 80o/o

rsasaki.K., Kubo,T., Sakai,M., Kuroda,Y. CL617(199'7). 2Kamekawa, H., Tokuda,M. CLgl'/ (199'l). H., Kudoh,H., Senboku, 3Courtois, J. f 53, 11569(1997). R.,Troupel,M., Perichon, V., Barhdadi, "Durandetti, J.-Y.JOC 62,7914(1997). M., Perichon, J.,Nedelec, 5crigsby,W. J.,Main,L., Nicholson, B.K. JOMC 540,185(1997). oJou,D.-C.,Hsiao,T.-Y.,Wu, M.-Y.,Kong,K.-C.,Cheng,C.-H.f 54, 1041(1998)

Nickel chloride-phosphine

complexes

Nickel chloride-phosphine complexes. 14, 125; 15, 122; 16, 124; 18, 250; 19,22'l -228 Ar-Ar couplings. A self-coupling of aryl triflatesl and halides2employs Zn-DMF. With the nickel catalyststhe Suzuki-type couplings3-5are more convenient. Coupling with alkenyl seleni.des. Stereoselective synthesis of arylalkenes (6 examples, 85-95Vo),6 1,4-dienes(6 examples,73-87%o)i by this method is complementary to other approaches.

,'SePh 1en.e1rruicr, ll

asePh (Ph3P)2Nicr2 i

l

-

Br/

r

l \ Y phMgBr/ THF 2so

tl \V

Nickel peroxide. Drpeptide cleavage.

3_MephMgBr / THF

_l

'Adoni, N. Yu., Ryabinin,V. A.. SrrrE -Indolese, A. F. ZI 3E,3513( 1997r. -Saito, S.,Oh-tani,S.,Miyaura-\..tO( 'Ueda, M., Saito,S.,Oh-tani,S..\ti1r ozhu, L.-S.,Huang,X. SC 27,39ttgy] 'Huang, X., Sun,A. M. SCt.272-s r lr uKobayashi, S.,Takahisa,E., Usmaor! eKobayashi, S.,Watatani,K., Tokqo. I r0lipshutz, B. H., Kim, s.-K.,Molhd. I llwille, A., Tomm,S.,Frauenrath. H. .5 '"Ager, D. J.,East,M. B., Eisensradr..L

25o 95o/"

The C-l

88%

Allylic subst'ttution with borates.s'e Arylation of allylic acetateswithout transposition using B-alkyl-B-aryl-1,3,2-dioxoborolidines occurs in the presence of (P\P)2NiCl2.Notetheexclusivetransferof thearyl group.

"),*/*A**

LI

Ho,,,/\,,"oAc \

\:/

/

Ph.-,/\ +

F

t

l

-

(Ph3P)2NiCt2

Ho,,,o/Ph

Nal / t-BuCN-THF

--r/\/-\)

250

Alkylation with ben4ylic halides. Chloromethylated p-quinones couple with RAlMe, by (Ph,P)rNi which is obtained from dechlorination of the complexed nickel chloride with BuLi.r0 An expeditious route to vitamins K, and I! is basedon this method. Isomerizati.on Allyl ethers and allyl acetals undergo isomerization to furnish the (Q-alkenyl ethers with (dppb)NiClr-LiBHEt,.rr On the other hand, the isomerization mediated by (Ph.P),RuClr-LiBHEt, is almost totally stereorandom.

o'^v\

w

'Easton, C. J., Eichinger,S. K., Pina V

(dppb)Nicl2 + LiBHEt3 / THF

v 8 1 o k( Z : F 9 5 : 5 )

Teniary phosphines.t2 A.yl triflates react with mediation with Zn and catalyzed with (dppe)NiClr. rJutand,A., Mosleh,A. JOC 62,261(1gg7').

diarylchlorophosphines by

Nitric acid. 18, 251-252; 19, 228 Hydrolysisof t-esterc. r-Bun (9 examples,92-99%).1

lStrazzolini, P., Dall'Arche, M. G.. Gruu

Nitric oxide. 19.229 Nitroalkenes,t A facile nrdl usinsNO in zeolites.

j lf

Nitrosations. Aromatic conp acetic-sulfuric acid mixrures.:Sq solvents.3

Nitric oxide

11 16.124;18,250;19,227-228 employsZn-DMF. s ,nd halides2 tB ltrrrB convenient, : .\ nthesis of arylalkenes (6 i :,. :his methodis complementary

"Adoni,N. Yu., Ryabinin,V. A., Starichenko, V. F. RIOC34,286 (1998). 'Indolese, A. F. TZ 38,3513(1997). "Saito, S.,Oh+ani,S.,Miyaura,N. JOC e2,8024(1997). -Ueda,M., Saito,S.,Oh-tani,S.,Miyaura,N. 254, 13079(198). ozhu, L.-S.,Huang,X. SC27,39(1997). 'Huang, X., Sun,A. M. SC27, 2725(1997). oKobayashi, S.,Takahisa,E., Usmani,S. B. fI, 39, 597(1998). 'Kobayashi, Watatani, S., K., Tokoro,y.TL39,7533 (1998). r0lipshutz, B. H., Kim, S.-K.,Mollard,P.,Blomgren, P. A., Stevens, K.L.T 54,6999(1998). "Wille, A., Tomm,S.,Frauenrath, H. S 305(1998). r2Ager,D. J.,East,M. 8., Eisenstadt, A., Laneman,S. A. CC 2359(lgg'1).

|:.-Nickel peroxide. Dipeptide cleavage.

THF

E:. 5

The C-N bond scission is selective to glycine moietiesJ

88o/.

o

f . , . . lri c acetates without trans5 \ a u r s in the presence of lut

Ph

H r l N

Y o

'ntilJ**,

Ni02

./\, N H

COOMe ---

5 r

PhH A

-

740/o

) ..^

Ho,,,o/.Ph

'Easton, (1997). C.J.,Eichinger, S.K.,Piua,M. J.253,5609

€-:'r-THF

2a

84"/"

rur'J p-quinones couple with t::.r:l()n of the complexed nickel K ::rJ K. is basedon this method. dc:- , rsomerization to furnish the tl^.c ,ther hand, the isomerization rt, rlndom.

Nitric acid. 18, 251-252; 19,228 Hydrolysisof t-esters. r-Butylandadamantylcarboxylates arecleavedby nitric acid (9 examples,92-99Vo).1 rStrazzolini, P., Dall'Arche, M. G., Giumanini, A. G. Z:L3g,9255(lgg8).

Nitric oxide.19,229 Nitroalkenes,r A facile methodfor the conversionof alkenesto nitroalkenesis bv usingNO in zeolites.

^ , -t r'" , '\.'31". (Z: E 95:5)

NO / CCr4 H-zeolite 75o

U

Noz

78"k

r:::

diarylchlorophosphines by

Nitrosatians. Aromatic compounds undergo nitrosation with NO in C{COOH or acetic-sulfuric acid mixtures.2 Secondary amides form N-nitrosamides in nonpolar solvents.3

260

Nitrogendioxide

Deamination, On exposure to nitric oxide and a catalytic amount of oxygen the group amino of arylaminesaand heterarylamines5is removed. Similarly, arylhydrazines are converted to the hydrocarbons although aryl azides are also formed as minor products.6 rSreekumar, R.,Padmakumar, R.,Rugmini,P. TL39,2695(1998). 'Atherton, J. H., Moodie,R. B., Noble,D. R.,O'Sullivan,B.JCS(P2)663(1997). 3ltoh,T., Nagata, K., Matsuya, Y., Miyazaki,M., Ohsawa, A. TL38,5Ol7(1gg':-). -Itoh, T., Nagata,K., Matsuya,Y., Miyazaki, M., Ohsawa,A. JOC 62,3582(199'7). 'Itoh, T., Matsuya,Y., Nagata,K., Ohsawa,A. CPB 45, 154'7(1997). oMatsuya, Y., Itoh,T., Nagata, K., Ohsawa, A. 253, 15701(1997).

Nitrido[Ntnr'-(1,1,2,2-tetramethyl)ethylenebis(salicylideneaminato)]manganese(V). 19,229 2-Aminosugars.l Glycals are functionalized. An amino group is introduced at C-2 (9 examples,62-80Vo).

OH

(saltmen)Mn(N)

pn""(o"'

(CF3CO)2O;

ph.'

,,,NHCOCF3

silicagel

tDu

MeHN HN

Nitration." Catalyzed b1 FeCl achieved with NO'-O., at abour O' derivativein excellentyield.

rSuzuki, H., Takeuchi, T., Mori.T. BCSI1 2Suzuki, ,I H., Nonoyama, N. ft 39.{5-1-1 rEvans, D. A., Carter, P.H.,Dinsmorc. CJ -Suzuki, H., Tatsumi, A., Suzuki.H.. It--d

2-(4-Nitrophenyl)ethylsulfonyl

chlc Hydroxylprotection,t Ribonrr cleavedunderaproticconditionson ur

tPfister, M., Schirmeister, H., Mohr.\l . Fr S.,Charubala, R., Pfleiderer,W. HC.t 71.

Boir,J.,Tomooka, C. S.,Hong,J.,Carreira, E. M. ./ACSllg,3l'1,g(lg9'1).

4-Nitrobenzenesulfonyl azide. *Diazo esters.t A brief reaction of B-keto esterswith 4-O2NC6H4SO'Nr-DBU and then with pynolidine accomplishesincorporation of the diazo group and disengagementof the acyl unit. cr-Diazoalkanoic esters of propargylic alcohols are readily prepared in this

o -Nitrophenyl selenocyanate. 1,3-Hydroxyl transposition.: A selenidesby reactionwith ArSd\-Br the presence of pyridine a sponurnc alcohols are liberated.

manner, lWeingarten, M. D., Padwa,A. Sl, 189(1997).

\ Nitrogen dioxide. 15, 219; 18, 252-253 Oxi.dativecleavage of methyl ethers.t Carbonyl compoundsare generatedwhen the ethers are treated with NO, water in the presenceor absenceof ozone. Without water but in the presenceof ozonethe reactionis slow. Iododeamination.2

Arylamines are rapidly converted to aryl iodides under nonaqueousconditions on treatment with nitrogen dioxide in MeCN and NaI. Hydrolysis of secondary amides.3 A mild procedure for hydrolysis of polyfunctional secondaryamides consistsof N-nitrosation and treatment with LiOH-HrOr. As featured in a synthesis of vancomycin a secondaryN-methyl amide is hydrolyzed without affecting a primary amide.

,^./:\_oH_-3!1*

r

rrY*

.%*q

tKri"l

A., Laval,A.-M. BSCF134.86O,IS

4-Nitrophenyl triflate. Triflation.t This stable, cqsu triflating agent for phenols.

4-Nitrophenyltriflate

cr:J.\tic amount of oxygen the rej \rmilarly, arYlhYdrazinesare l. :,,nled as minor Products.6 B t, r _' 66-i( 1997). , - r s< r l r t 1 9 9 7 ) . x 6::582(1997).

l lcneaminato)lmanganese(V). L-- -r,' :Iroup is introducedat C-2

OH

"'NHcocF3

I MeHN--{

I

orBS

No2/MecN.ol

J.

l;;:

.Xlo\__/-

tf,o"r"*\".

Na2so3

"o{

261

orBS A

^tVoJ bocr,

brt'rt

55"/"

Nitration.a Catalyzed by FeCl, the nitration of electron-deficient arenes can be achieved with NO'-O, at about 0'. Thus, trifluoroacetylbenzene furnishes the 3-nitro derivativein excellentyield. 'Suzuki,H., Takeuchi, T., Mori,T. BCSJ70,31I I (1997). 2suzuki,H., Nonoyama, N. 7L 39,4533(1998). 3Evans, P.H.,Dinsmore, C.J.,Barrow,J.C.,Katz,J.L., Kung,D. W TL38,4535(1997)D. A., Carter, aSuzuki, H., Tatsumi,A., Suzuki,H., Maeda,K. S 1353(1995).

2-(4-Nitrophenyl)ethylsulfonyl chloride. Ribonucleotides protected as the sulfonyl derivatives can be Hydroxyl protection.' cleaved under aprotic conditions on treatment with DBU involving a B-elimination process. lPfister,M., Schirmeister, K.-P.,Reiner,T., Dunkel,M., Gokhale, H., Mohr,M., Farkas, S.,Stengele, W. HCA78, 1705(1995). R.,Pfleiderer, S.,Charubala,

-qrl997). 9 I

r ::: -1-O.NC.H,SOrNr-DBU and of l:.,z. Lroup and disengagement in this prepared r\i, .. rre readily

o -Nitrophenyl selenocyanate. Allylic alcohols are transformed to the allylic 1,3-Hydroxyl transposition.) selenidesby reactionwith ATSeCN-Bu.,P.On further oxidation with hydrogenperoxidein the presence of pyridine a spontaneous rearrangement intervenes and isomeric allylic alcohols are liberated.

tu"

\Ny:\_on

HO

, v\.,l./:\-s"n,.9

61,sectr .:l\r.lo,

v^v^.,>\

940/"

;, :lr( )undsaregeneratedwhen the s':r,. ()f ozone.Without water but rr.: inL'd to aryl iodides under ric :: \leCN and NaI' tbr hYdrolYsis of PolYxl.,:r N ::.Jrrnentwith LioH-HrOr. As r:: .. .unideis hYdrolYzedwithout

tKriel A., Laval,A.-M. BSCF134,869(199'1).

4-Nitrophenyl trifl ate. Triflation.t This stable, crystalline, nonhygroscopic compound is a valuable triflating agent for phenols.

Nitrosonium tetrafl uoroborate

rzhu,J.,Bigot, A.,Elise,M.,Dau,T. H. TL38,1t8l OggT\. Nitrosonium tetrafluoroborate.14,215; 19,230 Isoxazoles't Halogenated cyclopropanes undergoring openingandincorporateNo to form substituted isoxazoles.

tn

NOBF4

(tt Br

MeCN 25o

Ph\,'V,Br \ \ / N-O

890/"

'Lin,

S.-T.,Kuo,S.-H.,yang,F.-M."/OC62,5229 lggT.

Organocerium reageot 19,231

Reaction with an*lt c,,c,-disubstitutedbenzl li even when the reagenris 1 for the ketone synthesis. casesof clsilylated denr

.+ a'ljA

MeoAz\z/

frl".Si ,,

(

Addition to imincs.

B-amino silanes is hingcd hydrazones.a Conjugated allylamines.5

'n*'{)

a-Silyl ketones.b Thc method for the accessof rhc

FE:.

-: rnd incorporateNO

./-Flr

( h-3 if:_

Organoceriumreagents.13, 206;14, 217_2lg; 15,221; 16,232;17 ,205_207; lg, 256; 19,231 Reactionwith amides. Benzamides and thiobenzamides are converted to o,c-disubstitutedbenzylamines.r Tertiaryamidesform ketoneson reactionwith RCecl, evenwhenthereagentis presentin largeexcess, thereforeWeinrebamidesarenotnecessary for the ketonesynthesis.2 Enaminones arealsoattackedat the carbonylgroup,andin the casesof c'-silylatedderivativesthereactionproductsarep,y-unsaturated ketones.3

\_

,-..-l-{ l u l \ )

MeCeC12 IHF

- t6-

MeO MeO

.YY" 95%

NHPh

r

Vfessiar\7\

BuCeCl2

B u O t t l /\/\

THF - 78o. 100/"Hcl

770h

Addition to imines- A diastereo- and enantioselective synthesis of protected B-amino silanes is hinged on the addition of organoceriums to a-silyl sAMp/RAMp hydrazones.a conjugated imines show regioselectivity that favors the generation of allylamines.5

tn..9A.2*\-1

Bucect2

t

\_,/

l

Et2o - 78o;

H

en.Taarttt \-'\ I (,

+

Bu

^Y-" Bu

53%

(90 : 10)

a-Silyl ketones.6 The reaction of silyl ketenes with RCeCl, represents a simple method for the accessof thesecompounds. 263

264

Organocopperreagents

- \_4 .O

Diastereoselectiveadd the entry crs to the estergr reacts with MeCu(CNllj

Me"Si

PhCeCl2

MellSi.

\

aq. NH4CI

Ph

79o/"

Alkenes.T Organoceriumsattack allylic alcohols by the S*2'displacement pathway. Thus, internal alkenes are formed from 1-alkene-3-ols.

fl-c,or

04^,{'i

Bn

Boc

LiH/rHF01

Rr,A/r,z\,2

3 RLi - CeCl3

'Calderwood, D. J., Davies, R. V., Rafferty, P., Twigger, H. L., Whelan, H. M. IL 38, 1241 (1997). 2Ku.o.u, M., Kishi, Y. TL39,4793 (lggS). 3.Dulpo"ro,R., De Nino, A., Bartoli, G., Bosco, M., Sambri, L., Marcantoni, E. JOC 63,3745 (lgg}). -Enders, D., Leriverend, C. fA 8, 278'l (1997). 5qian, C., Huang, T. JOMC 548, 143(lgg7). nAkai, S., Kitagaki, S., Matsuda,S., Tsuzuki, Y., Naka, T., Kita, Y. CPB 45, 1135(199'].). 'Dalpozzo, R., De Nino, A., Tagarelli,A., Ba(oli, G., Belluci, M. C., Bosco,M., Sambri,L. JOC 63, 9 5 5 9d 9 9 8 ) .

Organocopperreagents.13,207-209; 14,218-219;15,221-227 ; 16,232-238;17, 207-2 18; 18,257-262; 19,232-235 Conjugatead.ditions. Cuprateadditionto ynoateestersandtrappingwith aldehydes (in thepresence of EtrAlCl) providespecialanalogsof Baylis-Hillmanreactionproducts.r Trappingwith phosphonoacetatic estersis anothersyntheticallyvaluablevariation.2Silyl keteneacetalsderived from 1,6-additionto allyl alk-4-yn-2-enoates undergoClaisen reiurangement at roomtemperature.s Ph Me2CuLi/ Et2O ;

-........-.'........',...'....-

-COOMe

PhCHO

.

Fou

/

COOMe

H

A combinationof Tlu and permitstheir applica controlis manifestedin rh atom8 bondsaway.7

d\

?.

oAo

)Aa

Mixed cuprate reagen thermally stableyet highll tetramethylsilaneas by-prc

Introduction of organor heterocupratesis quite ga making available p-srann propargylic alcoholsro and

illustrated in a novel synrh for example, by sequenda PhMerSeLi, and an econor

71% (68.5%de)

catalytic in copper.

z*

OMe

OSiMe3 Me2cuLi - Me3SiCl Et2O

- 3Oo

a)4o

J

,oo

Hso* ; CH2N2

V"14" t \ r '

(Bu3Sn)prr

Vru

Organocopperreagents 265

Y

,o

Diastereoselectiveaddition to 4-substituted 2,3-didehydropyroglutamate estersrevears the entry crs to the estergroup.aunexpectedly, 5-(r-butyldimethylsiloxy)-2-cyclohexenone reactswith MeCu(CN)Li in a cls-selectivemanner(cis:trans>99:1).5

P

:9" "

t \

r Srl' displacement pathway.

F\

-a4', i

-cooet

'

*--"-'

a

n

Me2culi/ rHF

*

"

*

J oA'>"oo=' ,gn ,|

Boc

=

Boc

.---\,,'\A,/

'.i

73k

.,r. H. M. rL 38, t24t (1997).

A combination of rMEDA and Me,Sicl makes benzylic copper reagentsmore stabre and permits their applications to conjugate addition to c,p-unsaturated esters.6chelation control is manifested in the cuprate addition to conjugate estersby a trivalent phosphorus atom 8 bonds away.7

\'l ,-..::rr()ni, E. JOC63,3745(1998\.

a \l

':

l ' 8 . 1 5 . I 1 3 5( 1 9 9 7 ) . fi,sco, M., Sambri,L. JOC 63. Me2CuLi

5. l-.

?

PPh2

oAo

127; 16,232-238;17,

c.ir:. und trappingwith aldehydes 1.. :. Hillmanreactionproducts.l f,.': -.':lr valuablevariation.2Silyl l-:, . :r-l-enoates undergo Claisen

\

roH

,

COOME 71% (68.5%de\

l+.

Mixed cuprate reagents derived from RLi and (trimethylsilyr)methylcopper(I) are thermally stable yet highly reactive. They transfer the R groups efficientiy while giving tetramethylsilane as by-producton workup.8 Introduction of organostannyl and silyl moieties into organic compounds by means of heterocupratesis quite general. 2-Alkynoic acids accept a tributylstannyr group readily, making available B-stannyl-a,p-unsaturatedacidse in a straightforward manner. (Note propargylic alcoholsr0and ethynelr also undergo stannylcupration,the utility ofwhich is illustratedin a novel synthesisofcyclobutenes.)Silylcuprate reagentsare generatedin situ, for example, by sequential addition of Merzn and catalytic amount of Mercu(cN)Li, to PhMerSeLi, and an economicalmethod foi silyl transfer is established.r2 Such reactionis catalyticin copper.

Ph

\

93o/o (anti : syn gS:5)

OMe

2oa H:o* ; cH2N2

v"+" I

\

Z

-

(Bu3Sn)2CuLi / THF ; \---7

Y

TMEDA

oH /:\ Bu3Sr/ \-J

TsCl - Et3N;

Organocopperreag€nts

l-Aza-1,3-alkadienes containing an N-trimethylsilylmethyl substituent also undergo conjugate additions.l3 Allenes.ta The thiaphilic reaction of cuprate reagentson 2-alkynyl-1,3-dithiolanes gives allenyl sulfides. The residual sulfur substituent is replaceable by a Ni-catalyzed Grignard reaction.

sS.r.rS

\.2

tBu2culi ;

.----------------_ MeoH ,rr"

./-en Ph/t

Me

MeMgl

...s 1rn

(dppf)NiC12

-Ph

Ph 81"/"

88o/o

a-Amino acids.rs Copper enolates of amides react with N-lithio /-butyl tosyloxycarbamateto afford N-Boc derivatives of cr-aminoamides.An asymmetric version of this processis highly successful.

a.

\-N,

/

Pri

"';4g

-/o BuLi/THF-78o;

t('^\

l

+

)

CUCN; TsON(Boc)Li

/a

\2

,48

6NHcr

T

vo"

'wei. H.-x.. willis. s.. Li.c.TL39.8to_r r "Piva. O . . C o m e s s eS, . f L 3 g , 7 l 9 l t l 9 9 - , 'Becker, M., Krause,N. L4 725 ( 199- r -Guillena, G., Mancheno,8., Najen. C. Er 'Hareau-Vittini, G., Hikichi, S., Saro.F {C -van Heerden,P. S., Bezuidenhoudr.g. C I 'Breit, B . ACIEE 37 , 525 (tggg). oBertz. S. H., Eriksson.M.. Miao, G.. Snr,l .''Betzer. ' T h i b o n n e r J. . . L o u n a y .V . . A b a r b n .\ 1 . . ' D u J.-F..Delaloge.F.. Miiller. 8.. parx "Barbero, A.. Cuadrado.p.. Carcia.C.. func '-Lipshutz, B. H., Sclafani, J. A., Takanarnr_ ''Bonini, B. F., Fochi, M., Franchini. \l ( , ,Aizpurua,J.-M., Palomo,C. ,lL 132I r l99r '"Tseng, H.-R., Luh, T.-y . JOC 62.4566 r I 9 ',-Zheng. N.. Armstrong.J. D.. McWilhams. I '"Bergmeier, S. C.. Stanchina,D. M. -/OC al

Organocopper/zinc Preparation.

reagents. lE. 16: _ Alkylzinc_copper

r activated Zn and then with Cu(OAcl_1.-r Allylic displacements. n-Complcr

reaction with the organocopper/zinc rcq of configuration.2 For chain extensron nr is reacted with MeCu(CN)Li and rhen sr

,,.f{*",

Zn'- ire39(

86% (98% ee)

77% (>990/6del

rrpsoAr'\r\z' l,2-Amino alcohols.t6 By decomposition of allylic azidoformates to produce bicyclic oxazolidinone substratesfor ring opening reactions, a stereoselectiveentry into syn-1,2-amino alcohols is delineated. Thus, after treatment of the aziridines with organocopper species,trans-4,5-disubstituted oxazolidin-2-ones (14 examples, 55-9l%o) are obtained.

MsCu(Cr

\) 200

oH

Ao"'\

, P""r'^x*l > ( l N / to"'Y; "'o' 'a

tl 83%

m-substituted phenones.a olefination of tricarbonyl(qa-5-oxocyclohexadienyl) iron is accomplished by organolithium reaction at -78o followed by dehydration [HB{' (EtCO)rO; H2O, Al. m-Substituted phenones are secured on further reaction of the alkylidenecyclohexadiene tricarbonyl complexes with RLi (or higher-order cuprate reagents),carbonylation, and oxidative decomplexation (with MqNO).

rVarea,T., Grancha,A., Asenslo 2Aurell,M. Mestres, R.,Mum J., 3Hanrahan, J. R., Knight,D. \[' ( -Iwakoshi, M.. Ban,S. H., Harr sMyers.A. G.. Movassaghi. \i ./ "Ovaska.T. V., Roark,J. L.. SIE

Organomanganese reageDG Allylmanganese reactb

transferan allyl groupto vanc exchangewith MerMnLi (pr which can be used to open . provide 1,4-dienes.3 Cyclizntinn.a

Allyl

o

compounds furnish dihydroh reaction with Bu.MnLi.

fS.

sr_rr-y,Fe(Co)s

!-\J

B u L i ; a q .N H 4 C I ; C O ; M e 3 N O/ D M A

L,.V

?-"

G"/

Organomanganesereagents

Red.uctive coupling with tosylhydrazones.s chiral comoonentsbv this method. r

Carbon chains can be assembledfrom

..NrI

NNHTs

tl

TDSA/ I

+ l-i

= P 'h \,/ \,/' ^

C:,' :hediketonesafterreaction

THF- Er2O-780; HOAc - CF3CH2OH

: TDSOA/WPh I

I

95"k Rearrangement.b A remarkable transformation by catalytic amountsof MeLi on an allylic alcohol which contains a silylalkyne moiety is the result of a Claisen rearrangement of a 2-methvlenetetrahvdrofuranintermediate.

c

OBu

f)rv L.-,/

OH

t'.

ra:.'J acids behaveas Michael 1r.:rc'thyllithium to nitrones er '.,',rkup, due to a retro-Cope

v2 Ph-"\

:r

= , P""r-:*l x | .N._ ',O,z 'gt,---./, z 83"/o

--5-oxocyclohexadienYl) nr . f ll.'s ed by dehydration[HB{, d ,'n further reaction of the lI-: ,r)r higher-order cuprate th \le\O).

..) MeLi(cat.)

\s,".. 85%

rvarea,T., Grancha,A., Asensio,G. Z 51, 12373(1995). 'Aurell, M. J.,Mestres, R.,Munoz,E. TL39,6351(1998). 3Hanrahan, R., Knight, J. D.W. CC 2231(1gg8). -Iwakoshi, M., Ban,S.H., Hayashi, Y., Narasaka, K. CL 395(1998). sMyers,A. G.,Movassaghi, M. ,/ACSf20, 8891(1998). "Ovaska, T. V., Roark,J. L., Shoemaker, C. M., Bordner,J.TL39,5705(1998).

Organomanganese reagents. 19, 236-237 Allylmanganese reactions. Such reagentsformed from allyl halides and BuMnLi, transferan allyl group to variouselectrophiles.rAltematively, allylstannanes undergometal exchange with MerMnLi (preparedfrom MeLi and MnClr) to fumish the reactive species which can be used to open epoxides.2Acetylenes react with allylmanganesereagents to provide 1,4-dienes.3 Cyclization.a Allyl o-iodoaryl ethers, N,N-diallyl-2-iodoaniline, and related compounds furnish dihydrobenzofuran and indoline products via radical intermediateson reaction with BurMnLi.

-S -S

e("/

B u 3 M n L/i T H F

oo

n0

reagents Organozinc

Activated dibromides such as 2,2-dibromoalkanoic Alkylationlaldol reaction. amides5and a 1,3-dihalopropene6incorporate R from R,MnLi and apparentlygeneratenew organomanganesespecieswhich can react with aldehydes.On the other hand, Bu,MnLi can remove the functional group of c[-acetoxy and cr-(t-butyldimethylsiloxy) ketones and the resulting enolatesreact with aldehydesin a syn-selectivemanner.T Alkenylmanganese compounds generated by Acylmanganationofalktnes." reaction of alkynes with RMn(CO), undergo photocyclization with an alkene linkage five bonds away. Solvent plays an important role in the last reaction.

alkenyl halidesTand with aryl halides ! triflates make it possible to derive a bar the first of a two-stagedcoupling.u rrh

(r.,^.2\ "2

t"

I

CoBrz / THF _1oo

Meooctal-1Meooc-\ MeOOC. Z-

MeMn(CO)5

Meooc/\ -_\

I

rior^', ro/v

Zn' I JHF :

Arl / (dba)2Pd

54"/"

r.*

rro&

Fu3P

\\

Biaryls.e

r*,

Et2O

^[,i,|]:s^"rr The cross-coupling

of ArMnCl

with

aryl halides

and triflates

using

(PqP)2PdCl2 as catalyst is an alternative method to Ullmann and related reactions. tHoio, M., Harada, H., Ito, H., Hosomi, A,. CC 207'r.(199'1-). 'Tang, J., Yorimitsu, H., Kakiya, H., Inoue, R., Shinokubo,H., Oshima,K. 7I 38, 9019 (1997). 'Tang, J., Okada,J., Shinokubo,H., Oshima,K. f 53, 5061 (1997). *Inoue, R., Nakao,J., Shinokubo,H., Oshima,K. BCSJ 70, 2039 (1997). slnoue, R., Shinokubo,H., Oshima,K. JOC 63,910 (1998). 6Kukiyu, H., Inoue, R., Shinokubo,H., Oshima,K. CL'73 (1998). 7Hoio, M., Harada,H., Ito, H., Hosomi, A. JACS llg,5459 (1997). ol-ee, J. E., Hong, S. H., Chung, Y. K. 24 38, l'781 (199'7). eRiguet, E., Alami, M., Cahiez, G. IL 38, 439'7(1997).

2 -Zinc io - I, 3 -dithiane s are valtd 4-acetoxy-1,3-dioxanesserve a-( p 1,1-diarylallenesinvolves Pd-carallz

derived from 1-arylpropynes by lirhrer sp2-sp2 bond formation process r

2-cyclopentenones a facile synthesirof

BuLi; I f, /-S, ( fsiMe3 + l( \-S znct2 -, L

Organozinc reagents. 13,220-222; 14,233-235; 15,238-240: 16,246-248; 17, 228-234;18,264-265 Preparativemethods for diorganozincs (e.g., RZnEt) include photoinduced exchangeof alkyl iodideswith EtrZn under photochemicalconditions.rBenzylzincsare obtainedfrom benzylic mesylatesand Bu,ZnLi.2 Various derivatives of Me,Zn(R)Li, where R = Me, CN, SCN can be obtained from Me,ZnLi and RLi.r Diisopropylzinc which is availablefrom i-PrMgBr and zinc bromide can be used for effecting rapid IlZn exchangea and BlZn exchange,senabling accessto complex secondarydialkylzincs. Coupling reactions. Cobalt(Il) bromide catalyzes the coupling of diorganozincs RrZn, allylic chlorides and phosphateswithout disturbing the configuration of the double bond.6Other couplings useful for skeletal construction feature alkenylzinc compoundswith

PdO?.

a,

Triorganosilyl(dizincio)methanesc. alkca,

Pd-catalyzed couplings with ra 3-silvl-1.5-dienes.

Organozinc reagents

rl-. .'. 2,2-dibromoalkanoic i r: j rpparently generatenew | ::.J ,,lherhand,Bu,MnLi can rx'::r ..iloxy) ketonesand the

alkenyl halidesTand with aryl halides.8The different reactivities of benzylic halides and aryl triflates make it possibleto derive abenzylzinc reagentfrom 4-triflyloxybenzyl bromide for the first of a two-staged coupling, with the secondstep involving the triflate.e

!r:.: c,:t.il()Unds generated by r .'::h ln alkenelinkagelive

(:ztz^I "2

l(.r'

cl

z"

coBr, I txF _1 o o

A t l ) 90" (z >90"h)

MeOOC./^--.--1 x l H

Meooc\

I

54"/.

U*-'

MeOOC. a-.\-----\ Y N \ . il MeOOC'L-I2 5'l"h

i. :-.,.lrlesand triflates uslng r ::.i rclatedreactions.

i:-. {

rio(^t'

rrc/"/

Zn' I THF Arl / (dba)2Pd TfO Fu3P

fi'^r^l-V\cooEr /\4

A/ZnBr/ THF (dba)2Pd- dppl

cooEt

Based on reactionsof organoztncs 2-Zincio-1,3-dithianes are valuable rcagentgto synthesis of of cnli-1,3-diols.rrA precursors as serve 4-acetoxy-1,3-dioxanes which are species organozinc of the coupling Pd-catalyzed involves 1,1-diarylallenes By an halides.r2 with aryl exchange lithiation andLilZn by derived from l-arylpropynes C-2 of to substituent a dienyl process introduce to sp2-sp2 bond formation a facile synthesisof nakienone-Awas developed.rr 2-cyclopentenones

rL38,9019(1997)

BuLi: I f \ ,SiMe3I ,."rr.oo=, ,/-s,, ( FSiMe3 ---------*l\ X l-----.td znct2 rHF \-d znct I L

q--

7-S, ,siMe3 ( X \-S' \-cooEt 71"k

-;:

16,246-248;17,

lu.:: nhotoinducedexchangeof Br' zr lzincsare obtainedfrom c / RtLi,whereR=Me'CN' ,r.. ':. uhich is availablefrom n.of diorganozincs A- -.'Lrpling Ar ,,'ntiguration of the double lr. .: \L'nvlzinccomPoundswith

Triorganosilyl(dizincio)methanescan be usedto unite two carbon chains.Thus, stepwise Pd-catalyzed couplings with alkenyl bromides and allylic bromides leads to ra 3-silvl-1.5-dienes.

272

Organozincreagents

siMe2R _/\ BrZn- '2ng,

+

SiMe2R

(dba)3pd2.cHct3 E,r\ ///\ v

e,z?6pn

Ph

1,l-Bimetallic reagentsare availaHc /\rr,

to alkenyllithiums.23

+

R=Me 73% R=Ph 67% SiMe3

Brzn^2ns,

*

(dba)3Pd2.CHCl3tran.

"r$"n

. - - - - - - - - - - ^- * 1A"n"

',,.s'" ,Br M".Si\Z..A"n ,

SiMe3

/\/r"ao.

\ /

(

Reagents formed in situ by reaction of t-BurZnl with organic Addition to C:X. halides add to carbonyl compounds, such mixed zincates do not transfer their t-butyl group.rs o-Diazo-B-hydroxy estersare formed by treatmentof diazoaceticesterswith EgZn and aldehydes at low temperature.r6Allylzinc species derived from allylic esters add to carbonyl compounds to give o- or 1-adductsaccording to the nature of the latter.rT

(Y \

."S ;P=,

OAc I (Ph3P)4Pd

run,t",

v*"",

El2ZnI PbCHO

9*"",

'. \:/

L

i

r^'s& ZnBI2 | Etp

Intramolecular addition of orgarmt exchange and hydrolysis deliver prope different zincate reagents can lead to difl and cyclization.25

SiMe3 1-3rJl-; 7 Et2O -5oo

The bimetallic species derived from E,trZn and MeMgCl transfers an ethyl group to imines. Asymmetric induction is observedin imines derived from chiral amines.rs Addition reactions. Mixed diorganozincs of the type RZnCHrSiMe, donate the R group to enones.re After lithiation and LVZn exchange the zinc derivatives of N,N-dimethylhydrazones react with vinylsilane at the c,-position.2oZincated species are derived from dimethylhydrazones, vinylmagnesium bromide, and zinc bromide which afford o-ethylated products.2lIfbenzaldehyde is addedbefore workup a net cinnamylation results. The Ni(acac)r-catalyzed addition of diorganozincs to substituted phenylethynes proceedsin a highly syn-selectivefashion (>99Va).22

Et2Zn- Ni(acac)2

Ph-----Ph

(.yo/Y ' (

cooEt

NMP. THF;

...,......_

CuCN.2LiCl;

Cyclopropanols.26 Zinc enolara react with diiodomethane to give cyclo?

cooEt Bi

717"(E:Z >98:2)

reagents n3 Organozinc

.z

SiMe2R l

..

R=Me R = Ph

1,l-Bimetallic reagentsare available from reaction of allylmagnesium halides and ZnBr2 to alkenyllithiums.23

73%

-""'(o",

' B r

t

Y

67010

. ""rr,V...Arn

\/\zMsBr ZnBt2 I El2O

847"

r'

(

M

Hso'

80% (dr >95:5)

or: . : r-Bu,Znl with organic d, n,rt transfer their l-buryl idi:J./(ucetic esterswith EqZn estersadd to allYlic rJ :r,rm

Intramolecular addition of organolithiums to an enyne moiety followed by Lt/Zn exchange and hydrolysis deliver propargylcycloalkanes.z The reaction of a halide with different zincate reagentscan lead to different products, as shown by simple dehalogenation

r.i:.rrc of the latter.l7

and cyclization.2s

Li SiMe" -

SiMeg r-BuLi/ Et2O NMe2

2"/" an ethyl group to l. ::.rnst-ers 18 ir,,nr chiral amines. I RlnCH,SiMe3 donatethe R rg::he zinc derivatives of

-5oo

l

fcasiv". . ",,,,O

znBrz! Li

fc4siur". "",,O

r.r::,,rr.rr)Zincated speciesare xlc .rnd zinc bromide which k- .\ , 'rkup a net cinnamYlation r, ..rhstituted PhenYlethYnes

/

-

cooEt

-/-\

P.

Ph

- ' ' . r E : Z> 9 8 : 2 )

cyclopropanols.26 Zinc enolates generated from g-iodoketones and diethylzinc react with diiodomethane to give cyclopropanols.

274

Organozincreagents

Ene reactions. An allyl acetateacts as enophile toward an alkene linkage situated four bonds apart on treatment with a Pd(0) catalyst and then EtZnOlPl or diethylzinc.2s Cyclization by the enereaction pathway transposesthe metal to a new position. Allenylzincs generatedin situ also undergo z\nca-enereaction.ze

.oo"\

ll rr

pd(oAc)z-Buzp, a\.,.-...-,J /,,9 i l ' r i |

\ ---\

Et2zn;

|

I

-

.r,

I

\./

. ?'-t .

lt a\

r-BuoKatR + r I "r*

\

\f'

-J--

I so%

(-)-erythrodiene

Ketones. Ketones are readily obtained by the reaction ofthiol esterswith organozinc reagentsusing (Ph,P)rPdCl, ascatalyst.30The o-acylation ofaryl carbamatesvia organozinc speciessets up substratesfor the Baker-Venkataraman rearrangement,thus rendering the | accessto 4-hydroxycoumarinsreadily available.3

21to, S., Shinokubo, H., Oshima- K. II -'Oppolzer, W., Schrdder, F., Kahl. S , l8oppolzer. W.. Flachsmann,F. ft t. "Meyer. C.. Marek. I.. Normanl J.-F 'oTokuyu-u, H., Yokoshima, S.. !-arnr "Kalinin, A. V.. Da Silva. A. J. M.. L,o 32l-ung"., F., Piintener, K., StiirrFr. R .

Osmium tetroxide.13, 222-215. 236-240;18,265-267;19, 2.tl -:. Ch emoselec tive dihytlrorybi allylic alcoholsarepreferenriall)d nonconjugated dienesis favored: Asymmetricdihydrory latioa. bothends,producingmajorprodwl Anothertypeof polymer-bound Dl

Chiralphosphines.32 These important ligands can be obtained from chiral organoboranesby consecutivereaction withEtrZn and various chlorophosphines. lCharette, A. B., Beauchemin, A., Marcoux,J.-F.JACS120,51t4(1998). 2Harada, T., Kaneko,T., Fujiwara,T., Oku,A. JOC 62,8966(1997). ''Uchiyama, M., Kameda, M., Mishima,O.,Yokoyama, N., Koike,M., Kondo,Y., Sakamoto, T. "/AC,S r20,4934 (1998). -Micouin,L., Knochel, P.5L327 (199'7). 5Oestreich, M., Micouin,L., Knochel,P. ACIEE 36, 245(lgg'7). 6Reddy, C. K., Knochel, P. ACIEE35,1700(1996). Tlipshutz, B. H.,Ullman,B.,Lindsley,C.,Pecchi, S.,Buzard, D. J.,Dickson, D. JOC 63,6092(lgg8). nRossi, R.,Bellina,F., Ciucci,D. JOMC 542,113(1997). 'Rottlender,M., Knochel, P. ?t 38, 1749,]1997). loCere, V., DeAngelis,S.,Pollicino,S.,Ricci,A., Reddy,C.K., Knochel, P.,Cahiez, G. S 1174(1998). "Rychnovsky, S. D., Powell,N. A. JOC62,6460(1997). ''Mq S.,Zhang,A. JOC 63,9601(1998). ''Pour, M., Negishi,E. TL38,525(1991). r4Matsubara, S.,Otake,Y., Morikawa,T., Utimoto,K. SL 1315(199S). r5Kondo, (lgg'7). Y., Fujinami,M., Uchiyama, M., Sakamoto, T. JCS(P1)'7gg r6Moody, C. J.,Morfitt,C. N. S 1039(1998). "Kimura,M., Ogawa,Y., Shimizu,M., Sueishi, M., Tanaka, S.,Tamaru,Y. TL39,6903(1998). '8Alu-o, G.,Pacioni,P., Savoia,D. CEJ3,726(lgg'1 ). reJones, P.,Reddy,C. K., Knochel,P. T 54,1471(lgg8). '0Nukurnu.u, '..0gg(199'..). 8., Kubota,K. fL 38, ''Nakamura,8., Kubota,K., Sakata,c. "/ACSll9,545'l (199'1). "Stlidemann, T., Knochel,P. ACIEE36,93(1997). 23Bahr, A., Marek,I., Normanr, J.-F.TL37,5873(1996). 24lorthiois,E., Marek,I., Normant,J.-F. TL 37, 6693(1gg6i. 25uchiyama, M., Kameda,M., Mishima,O.,Yokoyama,N., Koike,M., Kondo,Y., Sakamoto, T. "/ACS r20,4934(199U.

K 2 O S O 2 ( O H ).2o

\r

.'A

K3Fe(CN)6Kp t- BuOH d

(cat')

Aminohydroxylations. Sere the conesponding N-chloro-l/-sod employed as nitrogen source in d complexed osmate. The products diamines.eIn one version the cinch through thiopropyl chains.T The regioselective process p-amino-c-hydroxycarboxylic rcrd

corresponding acrylic acid substrr anthraquinonemediatesenantiosclo

Osmium tetroxide

,s rJ irn alkene linkage situated hc:: F-IZnOTP?or diethylzinc'28 !- r .r new Position. AllenYlzincs

'3-oK -rrqn

)l,o

v\ ,r_

(-)-erythrodiene i..: ': rhiol esterswith organozinc , ' .,r I earbamatesvia organozinc frrn.,n !€lrl€Ilt' thus rendering the

'6lto,S.,Shinokubo, H', oshima,K' TL39,5253(1998)' 21Oppol"er,W., Schrdder,F'' Kahl, S' HCA 80' 204'7(1997)' t8Oppot"".,W., Flachsmann, F' TL 39,5019(1998)' tntnl.y".,C.,Marek,I., Normant'J'-F'TL37' 857(1996)' T'TL39' 3189(1998)' t"r;ily;.;, T'' Fukuyama' S', Yamashita' H.' Yokoshima' y (1998)' 3tKulinin,A. v., Da silva'A. i. M., Lop"', c' c', Lopes' s'c'' Snieckus' 'TL39' 4995 \' "l-*g".,'f., Piintener,K., Stiirmer'R', Knochel'P' IA 8''715(199'l)' -239; t5' 240-241; 16' 249-253; 17' Osmium tetroxide. L3, 222-225: 14, 235 -242 236-240; 18, 265'26'l ; 19, 241 By adding TMEDA to the reaction medium Chemoselective dihydroxylations' Reaction at the terminal double bond of allylic alcohols are pret'erentiuttyaifryO.o*yiated.r 2 nonconjugateddienesis favored at cx''o-Dienesundergo asymmetric dihydroxylation Asymmetric dihydrorylations' bothends,producingmajorproductswhicharehomochiralatthesecondafyalcoholsitesJ-s DHQD ligands has been developed'o Another type of polymer-bound DHQ and

..::r he obtained from chiral ... chloroPhosPhines' r

- cat' K2OsO2(OH)2

\,4.4 l r

ag8 ).

K3Fe(CN)6 K2CO3 t- BuOH 0o

L : r1 Kondo,Y., Sakamoto'T JACS

oH

9H

,oaAloi*** 6H

on

(34 : 1) 50%

Ph

D. JOC 63'6092(1998)' rrckson,

MeO

"oYYo

*Y* Ph

. \-

, ' S I 174(1998)' . : ! ' 1 .P . , C a h i e zG

-'^t

r 1997).

, lrru. Y. fL 39,6903(1998)'

T' "IACS ,c:r.-. \1.. Kondo,Y., Sakamoto'

(cat-) = l-Bu'8'e Cl'Ct{0)' Several carbamatesHTNCOOR (R Et'7 Aminohydroxylations. have been N-bromoacetamiderr and the corresponding N-chloro-N-sodio derivatives' employedasnitrogensourceinthereactionmediatedbybis.cinchonaalkaloidligand complexedosmate.Theproductsarereadilymanipulatedtogivetwopairsofchiral derivatives are linked to silica gel surface diamines.eIn one version the cinchona alkaloid through thioProPYlchains.T for the synthesis of protected The regioselective process is suitable p.amino-cr-hydroxycarboxylicacidderivatives(racemic'nochiralligandadded)fromthe the other hand, 1,4-bis(dihydroquininoxy)conesponding acryIic acij substrates.r2on anthraquinonemediatesenantioselectiveformationofN.benzyloxycarbonylphenylserine'13

276

Oxalyl-1,1'-bis(benzotriazole)

""rt,*oi#

tKatritrky,

A. R.. Lerc

bAr"

r^*^-\"J-\/

o

Megsi'-

Oxalyl chloride. 17 Nitriles.t Prin

K2OsO2(OH)2

tNaka.lima, N., Ubulau

H2O - ProH TOYo

'Donohoe, T. J., Moore, P. R., Waring, M. J., Newcombe, N. J. It 38, 5027 (199i). 2And.rr, M. B., Lepore, S. D., Sclafani, J. A. TL 38,4043 (lggi). 'Maier, M. E., Reuter, S. LA 2043 (199':.). -Takahata, H., Takahashi, S., Kuono, S., Momose, T. JOC 63,2224 (1gg9). 5Hoye, T. R., Mayer, M. J., Vos, T. J., Ye, Z. JOC 63,8554 (1998). oBolm, .1ggT. C., Gerlach,A. ACIEE36,741 7song, C. E., Oh, C. R., Lee, S. W., Lee, S., Canali,L., Sherrington,D. C. CC 2435(1gg8). oo'Brien, P., Osbome,S. A., Parker,D.D. JCS(Pl ) 2519 (1998). vHan, H., Yoon, J., Janda,K. D. JOC 63,2045 (1998). toR"ddy, K. L., Dress,K. R., Sharpless,K.B.TL39,3667 (tg98). "Bruncko, M., Schlingloff,G., Sharpless,K.B. ACIEE36, 1483(1997). '"Rubin, A. E., Sharpless,K.B. ACIEE36,2637 (1997). ''Tao, B., Schlingloff, G., Sharpless,K.B. TL39,2507 (1998).

Osmium tetroxide-N-methylmorpholine oxide. 19, 242-243 Dihydroxylations. The presenceofphenylboronic acid in the reagent mixture leads to dioxoborolidine derivatives which are more easily isolated when polyenes are oxidizedl Another modification is the use of microencapsulated oso, which is recoverable and

S-(1-Oxido-2-pyr*[ Decarborylatiot acidsintendedfor frt

^ gOO+

d ("Yo, ][o""ao{ tGu-".,

P., Anderson. J

Oxygen.18,268-26 Epoxidatians. aldehydesand alken mediafor sucheporx

reusable.2 'Gypser, A., Michel,D., Nirschl,D. S.,Sharpless, K. B. JOC 63,7322(1998). 'Nagayama, S.,Endo,M., Kobayashi, S.JOC 63,6094(199S).

Ph

Oxalyl- 1,1'-bis(benzotriazole). Oxamides.t Unsymmetrical tetrasubstitutedoxamides are readily prepared,using an amine at room temperatureat the first stageof the transacylation, then another amine in the presenceof NaH at a higher temperature(8 examples, 44-75Vo).

%\%

PhNHMe

THF

2OO

l{=Nr

3 to\*fi P h 6

83/o

V

.-B U N H M e THF

A

\\

O B u l l l

.,&N.. ' i ll P h o

Oxidation of sul system can be contrr proportion of the a

NitrobenzophenonesI Conjagated aUcl either palladiumclusr

Oxygen

o

'Katritzky,

A. R., Levell, J. R., Pleynet,D. P. M. S 153 (1998).

) - N H o :

\--\_.\

ll

: V 6 n

Oxalylchloride.17,241-242;18,267-268; 19,243 underthe Swernoxidationconditions. NitriJes.l Primaryamidesaredehydrated rNakali-a,N.,Ubukata, M. ZL38,20gg(lggi).

o

hexafluorophosphate. S-(1-Oxido-2-pyridinyl)-1,1,3,3-tetramethylthiouronium Decarboxylation.t The reagent1 is usefulfor esterificationof hinderedcarboxylic acidsintendedfor freeradicaldecarboxylation.

tlw-r

n'\ C l-i5 r 1998).

_ ' o ]s, i l. ?

{""

]Lo'

(1)

EtsN-DMAP, ,(""'(O>q

;;;*

FNtvtez NMe2

o

iFo"xo{l 78% (2 steps)

'Garner,P.,Anderson, ('1998). J. T., Dey,S.,Youngs,W. J.,Galat,K. JOC 63,5'732

rr'JJentmixture leads oir r.ncsare oxidized] t r. recoverableand

Oxygen. 18, 268-269: 19,243-244 Epoxidations. A novel Ru(III) complex is effective in the aerobic cooxidation of aldehydesand alkenes (10 examples,72-lOOVo).tPerfluorocarbonsare useful reaction media for suchepoxidationprocesses.2'3

02 / I-BUCHO

I

PhA/Ph

CH2Cl2l aq. NaHCO3

h.r prepared,using an n rn()theramine in the

O B u

*t':

i

l

r^,\N...

'i

ll

P h o

l

Oxidation of sulfur compounds. The oxidation of sulfides by the Or-aldehyde system can be controlled to reach either the sulfoxide or sulfone stage by varying the proportion of the aldehyde, in the presence or absence of a nickel complexJ'a Nitrobenzophenonesare obtained from the corresponding diarylmethyl sulfones.s Conjugated aldehydes, Allylic alcohols are converted to enals when treated with under molecularoxygen. eitherpalladium clustercomplexes6or Ru-Al-Mg hydrotalcitesT

278

OxYgen

the The oxygen/DMSO couple recycles As reoxidant of palladium catalysts'8 of conjugatedcyclohexadienes' Pd(II) speciesfor 1,4-difunctionalization to and oxygen' phenols are oxidized tyrosinase of In the presence Quinones. o-quinoneswhicharecapturedbydienophilessuchasethylvinylether'9Chemicaloxidation (6 examples' 36-657o) is mediated by a to p-quinonesro in ttnu*ing benzene "rfi""tt acid' mi^tor" of Co and Mn salts of 4-aminobenzoic

w

oz/ cHcr3 | (Xt

I

V ,-11

\.,,oEt

h'a

G;i L*" i

\'oprcctnr bKalrcor K. I Kancde-K.' \oorr. \l . .t o\lull.'. G H ttastrmr. V ''Adanr. s'-

Saha-Molb ::Blay. G-. Fo

lllT (l99tl :lPaersgl K ttc,os*emi. S '\ea:rmro..

o

a\ t(oH

1rc. r r'. S

oEl 70"/"

from peas mediates the enantioselective various oxi.dations. An cr-oxidase 'r I on acidslto give productsof (R)-configurationl oxidationof hydroxylationof carboxylic theotherhand,a.hy

0:.

Lr-1

3327(r99$. t3P"t".ron, (1993). R.C.JOC63,3185 K. P.,Larock,

racoswami,S.,Mahapatra, A. K. TL 39, I 98I ( I 998). r5v"d".nikou,A. N., Sayakhov,M. D., Solomonov,B. N' MC 205(1997).

oEt 70o/.

rc. :he enantioselective ,:,& configuration]O . r rn rr .lnJ the processrenders

Ozone. 13, 229; 15, 243-244; 17, 253-254; 18, 270-27 2; 19, 244-246 Tandem reactians. Homoallylic alcohols are obtained when ozonides are treated with zinc and allylic bromides.rZinc performs two tasks:to reduce the ozonidesand to fonn nucleophilic agents. Ozonides.2 Treatment of a mixture of ketoxime etherswith ozone in the presenceof carbonyl compounds leads to ozonides.

,. .,'nipounds with the n:.::. toward (Ph,P)CoCl .

.jitions aldehydesare

\ /

FNoMe *

01

,/-cl \-61

Og

cl o-o I )\.^,,^.

pentaneoo

cl 55%

F,HO Solid-phase synthesis. Terminal double bonds in polymer-linked compounds (e.g., esters)can be cleavedby ozone.l

,

X

tr$

''\/\)-

Bu4rcl Dr#

HoAc- H2o 100%

X = CHO,Ac, Bz, NO2

R=H,X=CHO

43"/"

IG 9,l0-Diarylidene-9. of (Ett cross-coupling at the l" 2-hydroxybiaryls

rLarock, R. C.,Doty,M. J.,Han,X.TL39,5143(1998)' 2l-arock, R. C.,Han,X., Doty,M.J.TL39' 5713(1998)' 3Dyker,G.,Grundt,P.,Markwitz,H., Henkel,G. JOC 63'6043(1998)' aWang,Z., Lu, X., Lei, A.,Zhang,Z.JOC 63'3806(1998).

Palladium(Il) acetate-oxY gen. The synthesisof biaryls from arylboronic acids' and l,3-dienes oxidative couplings. under mild conditionsinvolves the Pd(OAcl-O, syst'em' from alkenylstannanes2 Various primary and secondaryalcohols are oxidized to give aldehydes oxidations, Modified and ketones3by Pd(OAc)r-Or-pyridine in the presenceof 34 molecular sieves' and system Pd(oAc)2-o, the employ and chloride copper obviate which processes wacker a water-solubleI , l0-phenanthrolineligand or polypynole as redox-activeligand.s The preparation involves addition of primary amines N,N,-Dinlkylcarbodiimides.6 iodine is also required' Pd(OAc)r-O, to In addition to isonitriles. complex catalyst preparedfrom Pd(oAcl, A rnor. alkynes.t of cyclotrimerization and MsOH under oxygen promotes molybdovanadophosphate, chlorohydroquinone,a alkynes. from formation of benzenederivatives ,l31 lsmith,K. A., Campi,E. M., Jackson' G B' SL C' G' M', Deacon' S.,Naeslund, W. R.,Marcuccio, /1991\. 2Al.u.ur,L., Taylor,R. J. K. SL 791(1997). rNirhirnrr",T., Onone,T., Ohe,K., Uemura,S. fL 39,601I (1998)' atenBrink.G.-J..Arends,I. W. C. E.,Papadogianakis' R' A CC 2359(1998)' G , Sheldon, 5Higuchi, S.,Hiro,T. SL l2l3 (1996). M., Yamaguchi, uPri-Bor, J. CC 34'7(1997). I., Schwartz, TYnkotu, S.,Ishii,Y. IL 38, 3923(1997)' Y., Sakaguchi, T., Sakurai,

Palladium(Il) acetate-phase transfer catalyst. An intramolecular version is exploited in closing the five-membered Heck reaction is via ring to completethe tetracyclicsystemof mappicine.rA new synthesisof B-ketoesters Additives products? the Heck reaction of aryl halides with the Baylis-Hillman reaction have importantintluenceson the productsderivedfrom aryl halidesand 2,3-dihydrofuranl

f]r-' va,

The Heck reactioni\ a 1,2-dihydroq indolines,6'7 is u iu diastereoselectivitY

Reaction of 2-cYanothiod

(Y' \,

.\, mapprcrne

ruHcoc

rurr.

Palladium(Il) acetate-phase transfer catalyst

R

o'\/\J

\--l

,

X

Ph

Y-> \__JJ

a.o

Pd(OAc)z + Bu4NCl- KOAC DMF

Pd(OAc)2

Ph

Bu4NBr DMF

97"/"

100" R = H .X = C H O

437" 9, I 0-Diarylidene-9, 10-dihydroanthracenes are available as (EIZ) mixtures from self Of interest is the regioselective arylation of cross-couplingof (E)-o-bromostilbenes.a 2-hydroxybiaryls at the 2'-position.5

Ph

- Lict, Pd(oAc)z

r:: .::, lhoronic acidsl and 1,3-dienes r P.: ( ) \c)"-O, system. . .rrcoxidizedto give aldehYdes s .o d i f i e d I ' i \ m o l e c u l a r s i e v eM n. r the Pd(OAc)r-O, sYstemand r, - .t. rcdox-activeligand.s rr ..:. addition of Primary amtnes o '-',;.rired.

K2CO3 BuaNBrDMF

*

r - ,'.rlrst preparedfrom Pd(OAc)r' e \l-OH under oxYgen Promotes

11oo 80%

The Heck reactionis applicableto the synthesisof benzo-fusedheterocyclesincluding Influenceof reactionconditionson and benzopyrans.e 1,2-dihydroquinolines,8 indolines,6'7 is witnessedin the cyclizationleadingto geissoschizoland its isomer'r0 diastereoselectivity with aryl halidesintroducesthe aryl groupto the 5-position'1r Reactionof 2-cyanothiophene

, . B. SL l3l . . i .C . G . M . , D e a c o nG Pd(OAc)2- K2CO3 DMF - H2O ( 9 :1 )

R A. cc2359 (1998).

+ Et3N,Ph3P + BU4NBT

i

rJ in closingthe five-membered is via ....r nthesisof B-ketoesters Additives :' rcrction productsi

t:

. hllidesand 2.3-dihydrofuranl

P \

'fu

/-Ts

,yNHTs

10"k

490/"

Pd(OAc)2- K2CO3

( 1 0: 1 )

Pd(OAc)2-Na2C03

-.

491"

147"

DMF - H2O

NHCOOBn

.6-

RCHO/ DME

Ph

t

t

-

-

^ Y o -1 tl -l l r -

fi-\ r

ll )-soz

|

J

I

Ph

J

I

\_/8'lo/" (E:Z = 99:1)

rMisetic, A., Boyd,M. K. IL 39. 1651

Phosphazene.

Biaryl ethers.t The Utlmanr reaction temperaturecan be lorr eru

tBlakerno.", P. R., Cole, W. J., Kocienski,P. J., Morley, A. SL 26 (1998).

tPulorno, C.,Oiarbide, M., Lopez.R . C

p-(Phenylthio)acryloylsilane. 4-Hydroxy-2-cyclopentenones.The reagentreactswith ketoneenolatesto form functionalized cyclopentenolderivatives which on exposure to TBAF leads to 4-hydroxy-2-cyclopentenones.r A successful application of themethodto thesynthesis of the

Phosphorus(V) oxide. F rie d eI -C rafts alky latio n-' agents the reaction with activared producesI . l-diarylalkanes.

Phosphorus(V)oxide

to Bc: .tr room temperature Thus' l .'r.,nrples.80-997o).

309

clavulones has been reported. The 2-pyridylthio analog is also useful, if the initial adducts are treated with aqueous FIF in MeCN to complete the reaction sequence.2For the synthesis of 3-chloro-4-hydroxy-2-cyclopentenones (B,p-dichloroacryloyl)trimethylsilane is used.

LTMP

u:. :r,'nalizationof carbonYl ic( in MeCN (21 examPles' CsHtt F-

'Takeda,K., Nakajima,A., Yoshii,E. 5L255 (199'7). 2Tuk"du, K., Ohtani,Y., Ando,8.,Fujimoto,K., Yoshii'E., Koizumi'T. CL 1157(1998)' or'.:Luteddouble bond to a t\..1:r\rnby the Se-substituted r: .r:u eliminationcompletes

9-Phenylxanthen-9-yl chloride. The pixyl ethers are formed by a mixture of the Protection of prtmary alcohols.t presence of pyridine. Theseethersare photolabile, therefore chloride I with RCHTOH in the their cleavagecan be accomplishedwithout affecting many functional groups.

3,.s'.. to sulfones involves u : \ICPBA. DeProtonation 5: .:. :Je in DME followed bY

(1)

'Misetic,A., Boyd,M. K. 7L 39, 1653(1998).

Phosphazene. Biaryl ethers.l 81ok (E:Z = 99:'t\

The Ullmann synthesisis improved by using phosphazenebase.The reaction temperaturecan be lowered substantially (e.g., in refluxing toluene). lPulo.o, C.,Oiarbide, E. CC 2091(1998)' M., Lopez,R.,Gomez-Bengoa,

$:::. ketone enolatesto form lF\'..rrc to TBAF leads to |r' ::*-thtd to the synthesisof the

Phosphorus(V) oxide. when 2-methoxyalkanoic acids are used as alkylation Friedel-crafts alkylation.t agents the reaction with activated arenes induced by PrOr-MsOHl or PrOr-TfOH2 and producesl. I -diarylalkanes.

Platinum(IV) chloride

J

oR +

ArH

p2o5 - MsoH +

cOOH

Ethyl alkoxyacetales.3 \'anour O-H bond insertion of alcohols. phc ethyl diazoacetate.PtCl2 is slighrlr nr

Ar Ar

Ar = 4-MeOCoHa 9Oo/o Tetrahydroisoquinolin-I-ones. A significantly improved reagentfor cyclization of phenylethylcarbamatesis the P'O'-POC1, combination.3 rYon"ru*u,N., Tokita,Y., Hino,T., Nakamura, H., Katakai,R. JOC 61,3551(1996). 'Yonezawa, N., Hino, T.,.Tokita,Y., Matsuda,K., Ikeda,T. T 53, 1428'l(199'l). 3Wang, X., Tan,J.,Grozinger,K.TL39,6609(199S).

Polymethylhydrosiloxane. Reductions. Aldehydes.i arom the presenceof BuoNF. Aluminum c

Pivaloyl chloride. 18, 294 Hydroxylprotection. The selective pivaloylation ofhexopyranosides by PivCllor N-pivaloylimidazole2 lwhich is preparedfrom PivCl) is interesting.

oH'-oH

-fcocl

t \

Hovs,.,sPh

OH-OPiv

t \ PivoVS..sPh

reductive cleavage of 2-phenyl- I .-ldr from the 4.6-benzylidenesugarst.'

Deoxygenation. Thionocarbqt decomposedby PMHS using (Bu.S comparableto that employing sroichro benzylic ethers remain unscathed.

rKobayashi, Y., Takahisa,8., Nakano.\l . 'Drew, M. D., Lawrence, N. J.,Fontarrr.D 3chandrasekhar, S.,Reddy,Y. R.. Ramax -Lopez, R. M., Hays,D. S.,Fu,G. C. .r.{C

OPiv

OH

lBoverie, S.,Simal,F.,Demonceau. A .\ TL38.7543(1997). 2Baidossi, W., Lahav,M., Blum,J. J(f aJ 3s"hilr, R.,Simal,F.,Demonceau. A.. \ci 39,7849(1998).

787o N-Acyloxazolidin-2-ones,3 A convenient N-acylation of heterocyclesis performed by heating a carboxylic acid with PivCl and triethylamine in toluene. rJiang,L., Chan,T.-H.JOC 63,6035(1998). 'santoyo-Gonzalez, F.,Uriel,C.,Calvo-Asin, J. A. S 1787(1998). rPrashad, M., Kim, H.-Y.,Har,D., Repic,O.,Blacklock,T. J. TL39,9369(1998).

Potassium J-butoxide. 13, 252-1-il: I t-BuEl esters.t By subjecring temperature,exchangeofthe alkll gro

Eliminations. Based on an reaction between MeONHR and ehc synthesized.t-BuOK is an excellenrb

compounds also undergo elimination t Platinum0V) chloride. Cyclopropanation.t

Platinum(IV) chloride is able to induce the formation of cyclopropanecarboxylic esters from alkenes and diazoacetic esters at 80' (10 examples, '70-95Vo). Hydration of alkynes.2 The reaction is carried out under CO, in either aqueousTHF or tefachloroethane with a phase-ftansfercatalyst. Hft(CO)2Cl is consideredthe actual catalyst.

co / Ptct4

/\ Ph

ctcH2cH2cl Aliquat336 11 o o

I

n

f i l

\

l/J^ - y*'^l- G.*

Isomerimtions. Asynthertcalll triquinanes to the angular isorners.tFo microwave promotion is advanrageou

Potassiuml-butoxide

Ethyl alkoxyacetates.3 Various ptatinum(IlflV) salts and complexes catalyze the O-H bond insertion of alcohols, phenols, and acetic acid by carbenoids generatedfrom ethyl diazoacetate.PtCl2 is slightly more efficient than PtClo.

Ar

ls3 -

311

Ar r'= 4-MeOCoHa 9O"/" n:.! rntprovedreagentfor cyclizationof

lBoverie,S.,Simal,F., Demonceau, I. L., Sidorov,A. A., Nefedov,S.E. A., Noels,A. F.,Eremenko, TL38,7s43(1997). 2Baidossi, W., Lahav,M., Blum,J. JOC62,669(1997). 3s"hilr,R.,Simal,F.,Demonceau, I. L., Sidorov, A. A., Nefedov, S.E. ft A., Noels,A. F.,Eremenko, 39,7849(1998).

A:: :l

[ . R J O C 6 1 , 3 5 5(11 9 9 6 ) . ' (1997). T 5-r.11287

Polymethylhydrosiloxane. Reductions. Aldehydes,l aromatic acids and their esters2are reduced by PMHS in presence of BuoNF. Aluminum chloride is also an effective catalyst in the selective the and dioxolanes(e.g.,4-O-benzylderivatives reductivecleavageof 2-phenyl-1,3-dioxanes

by PivCll or rl::: ,n of hexopyranosides . rnteresting. C.

from the 4.6-benzylidenesugars).r Thionocarbonates derived from alcohols are reductively decomposed by PMHS using (Bu.Sn)rO and AIBN as catalyst, and the efficiency is comparableto that employing stoichiometricquantity of Bu,SnH.aUnder theseconditions Deoxygenation.

benzylic ethersremain unscathed.

lHaoPiv li-\-O Pivogs,-sPh

rKobayashi, K. 753, 1627(lgg7). Y., Takahisa,8., Nakano, M., Watatani, 'Drew,M. D., Lawrence, D., Sehkri,L., Bowles,S.A., Watson,W. SL989(1997). N. J.,Fontaine, 3Chandrasekhar, C. SC 27,2251(lgg'7). S.,Reddy,Y. R., Ramarao, 'Lopez,R. M., Hays,D. S.,Fu,G. C. JACS119,6949(199'/).

OPiv 78"/" r. ' i.rtion of heterocyclesis performed i::.rnc in toluene.

'-

Potassiuml-butoxide.13,252-254:15,2'71-272;17,289-290;18,296-297l'19,273-275 t-Butyl esters.t By subjecting esters to t-BuOK-t-BuOAc in THF at room temperature,exchangeofthe alkyl group takesplace (10 examples,88-99Vo). Eliminations, Based on an addition-elimination sequence initiated by Michael reaction between MeONHR and electron-deficient alkenes, functionalized enamines are synthesized.r-BuOK is an excellent base to promote such reactions.2'3cr-Azido carbonyl compounds also undergo elimination to give a different type of enamines.a

reS).

/ 1_39.9369(1998).

c :- .rble to induce the formation of estersat 80" (10 examples' d:.1/,,rcetic n: ,.rtunderCO, in eitheraqueousTHF or t( ( ) .Cl is consideredthe actualcatalyst.

Z\1^\

t-BuOK; 'l-NHBoc .......................'..'.'...."""..............* I ll

- DMAP (t-BuO)zCO

.y*-(

H

b

460/"

o

l

\

. t l l ) - o

YM'n lo l

(o\

P

h

Isomerizations. A synthetically useful transformation is the rearrangementoflinear triquinanesto the angular isomers.SFor the conversion of propargyl ethersto allenyl ethers microwavepromotion is advantageous.6

m'l I ltl

tlrl il:l

3r2

Pot.sium ,-butoxide

l lB"ll"., M., Riermeier.T ''Foray. G.. penenon. A I '-Evans.p.. Taylor. R. J. K

I-BUOK/ t-BuOH

64y"

olefination and cycropropanation. preparation of alkenyl allyl ethersby the wittig reactionT is readilyachieved.Telruriumandarsonium ylidestendto producecyclopropyl ketoneson reactionwith enones.8

Ph.P-)

o

rNayak, M. K., Chakraborn. 'Boas, U., pedersen,B.. Chn

cl \\ 7804

siMes .

=

iauri")

i

I-BUOK I

t'- -

/

SiMe3

1-iBu2re4

t^

ph

^

I ,,.\--\^ Y"/

I

I

.*;-

SiMe3

f

cyclizations. A route to substituted naphthalenes by intramolecular cyclizatione involves attack by a nascentallyl anion to u k"ton" g.oup. on the other hand, the generation of N-arylindolinesl0 from-arylamines and o-halosry-renes ls a more complex process. Arylamines. The pd-catalyzed arylation of amrnes dependscritically on r-BuoK.l r synthesis of surfur compounds. a,-Sulfenylation under mild conditions is realized by reaction with iy'-phenylthiocaprolactam.r2 An appropriate milieu is provided by I-BUOK/DMSO. Cinnamyl sulfides are prepared from BnSOTC(Br)=CH. and RSH promoted by r-Buo6.t: Ramberg-Biicklund reaction fbllows the initial addition. j:,i".I. M-.G.,Gagne.M. R. Joc 62.8240( tssT ). 'Seko, S..Komoto,I . JCS(p I ) 2g:l5(lggfir. 'Seko. S..Tani,N. TL 39.8tt 7 ( 1998). -Armstrong, J. D., III, Eng,K- K., Keller,J. L., purick, R. M., Hartner,F. W., Jr.,Choi,W._B.,A skin, R. p. Za35, 3239(tgg4\. .D., Volanre, MacDougall,J. M,. Moore.H. W. JOC 62, 4554( tggT). F. M.. Emami.R. sc 27. 4073ilssT ;yt:ghadd1m. ).

o, s, Rasne, R.M.ir tt, t+sssse7. ;f:]|T'..."l^T, Y l:"$*jar,rD . Dai, L._x., sun, r.,Xia,w.roc 62,ss4(tsel). ,)!j:1 I.l de Koning, C. B., p,,

r'"Beller'

Potassiumfluoride. lJ. Deesterifuatinn.: PhSHusingKF asbaser Tetramethylfluorola from tetramethylurea b1 , mediatingthecondensa CS, in thepresence of Fr

Michael, J. Rousseau,A. L. TL 3g, gg3(lgg7). M" Breindr, c., Riermeier, T. H., Eichbereer, tut.,i.uuttr*"rn,

H. ACIEE 37,3389 o 99g).

Potassium fl uoride/aluu As base. Manv rea for example, in deproron indole2 which is basc q,-heterosubstitutedWeinr

Microwave faciliraes aldehydesaand dehydrobn

rshi, D.,Lu,2.,wang.S..Tu 'Smith, W. J.,Sawyer, J. S. ff -Tius, M. A., Busch_peter: -Villemin, D., Martin,B. SC2 -Saoudi, A., Hamelin,J..Bcn

Potassium hydrogen fluor Hydrofluorination.i into fluorides at room temp

'Tamu.a, M., Shibakami. \1.. t( Potassium monoperox!.sul 300;19,217

Epoxidations. A mrr is an effective epoxidizing epoxidation of a prorrr

4-oxothiane-S,S-dioxide. an

asymmetricepoxidationof i ketonesand [email protected]

Potassiummonoperoxysulfate(Oxone@)

F

:

:

-

\

)

I rBeller, M., Riermeier, T. H., Resinger, C.-P., Herrmann, W. A. ?t 38, 20'73(lgg7). '"Foray, G., Penenory, A. B., Rossi, R. A. ZL 38, 2035 (199'1). "Evans, P., Taylor, R. J. K. SL lM3 (1997).

I

F

313

O

H

Potassium fluoride. 13, 256-257 ; 15, 272; 18, 297 -298; 19,27 5-27 6 Deesteriftcation.l Carboxylic acids are recovered from estersby an alkyl transfer to PhSH using KF as basein catalyticamounts.

640/o

rr . ., .r I ethersby the Wittig s-.: 1,,producecyclopropyl

Tetramethylfluoroformamidinium hexafluorophosphate.2 The reagent is prepared from tetramethylureaby consecutivereactions with POCI, HPF., and KF, and finds use in mediating the condensationof acids and hydrazine (to form hydrazides) and of amines and CS, in the presenceof Et3N (to form isothiocyanates). INayak,M. K., Chakrabom,A. K. CI, 297(1998). 'Boas, Pedersen, U., B., Christensen, J. B. SC28, 1223(1998).

-

,ro'^'J/

t - \

Potassium fl uoride/alumina. As base. Many reactionsthat are promoted by a basecan be effected with KF/Al2Oj, for example, in deprotonatingmalononitrile for Michael reaction.rin N-pyridylation of

78%

=-

'Y" '/)

Dh

SiMe3

^

I

-_\

Ph

I l-.::.!nt()lecularcyclizatione r :::r hand,the generation t,:r , ()tllplexprocess. n ; . - r r t i c a l l yo n t - B u O K . r :.:.J ionditionsis realized [c ::rrlieu is provided by rSrt ('i Br)=CH, and RSH k' :::rtrrladdition.

indole2 which is based on the S*Ar mechanism, and in the preparation of o-heterosubstitutedWeinreb amides from N-methoxy-N-methyl chloroacetamide.l Microwave facilitates the KF/ALo3-promoted condensation of oxindole with aldehydesaand dehydrobromination of yic-dibromides to bromoalkenes.5 'Shi, (1998). D., Lu,Z.,Wang, S.,Tu,S.,Dai,G. SC28,4003 2slnith,W. J.,Sawyer, H 51, J. S. 157(lggg). 'Tius.M. A.. Busch-Petersen. J. SL 531(199?). aVillemin. D.,Marrin,B. .tC28,320| ( 1998). sSaoudi, A., Hamelin,J.,Benhaoua, H. TL 39,4035( I 998).

Potassium hydrogen fluoride-silicon tetrafluoride. Hydrofluorinatian.t This combination readily transforms unsaturatedcompounds into fluorides at room temperature(4 examples,5l-95Vo). 'Tamura, M., Shibakami, M., Kurosawa, S.,Arimura,T., Sekiya,A. CC l89l (1995).

Potassium monoperoxysulfate (Oxone@).13, 259; 14,267:15,2'74-275;16, 285; 18, [ '\ . Jr..Choi,W.-B.,A skin,

Epoxi.dations. A mixture of Oxone@ and an iminium salt derived from pyrrolidine is an effective epoxidizing agent.' An imino group can also be exploited for directing epoxidation of a proximal double bond.2 The oxodiazepinium salt 13 and 4-oxothiane-S,S-dioxideaare also general and efficient catalysts. A popular approach to

I

Ftti

300:19.277

\ ( t E E 3 7 , 3 3 8(91 9 9 8 ) .

asymmetric epoxidation of alkenes is based on generating dioxiranes in situ from chiral ketonesand [email protected]

314

Potassiummonoperoxysulfate(Oxone@)

,,\

I

-\

o

\

N

oxoneo;

+

|

H

+

\

B

n

)

M

e

o

/'-,'2

J-,-aJ

\

r

f

:

t \-/

l

aqNaHCo3

Ox id.ation of nitro gcnt alkanesraare oxidized to kc formed under different corxt give c,-chloroniftoalkanes:i

).-/.= ( \ t F o \* / 2r1a ,,.Na

The formation of diplrr presenceof carboxylic rids Episulfunes.2o Eprs

(1)

Oxone@-trifl uoroacetonc.

Oridation of carbonyl compounds. Oxidation of aldehydesto acidsewith Oxone@ is accomplished in aqueous acetone. The conversion of c-acetyl-Y-butyrolactone to 2-methyltetrahydrofuran-3-oner0may involve hydroxylation, decarboxylation, and ring closure of the dihvdroxvketone.

oxone@

, NaOH - Na2BaOT aq. KOH

Either diacids or the monoa-Nitrocycloalkanones undergo oxidative cleavage. rr reaction conditions. may be acquired by adjustment of the methyl esters

Noz oxone@

....€

cooR OMe R=H,Me

Regioselective oxidation of trifluoromethyl ketones (via dioxiranes) occurs at the unactivated 6-carbon atom 12

o\.'co(

rArmstrong, A., Ahmed.G . ( 2A.rnrtrong,A.. Draffan.A ( lDenmark, S. E.,Wu.Z. JOC aYang, D., Yip, Y.-C.,Jiao.C sWang,Z.-X.,Shi,Y. JOCaI 6zhu,y.,Tu,Y., Yu, H..Shr iSong. C. 8., Kim. Y. H.. L.c 8Yang,D., Yip, Y.-C.,Tang. I 'Webb,K. S.,Ruszkay. S.J I loRagoussis, V., Lagouvardo llBallini,R.,Curini,M., Eprfr l2Yang. Y.. Wong.M.-K..\tr'r lsBore,D. S.,Srinivas, P.SCI laCeccherelli, P.,Curini.M..t l5Bose. D. S..Vanajatha. G. S l6Bose, D. S.,Narsaiah, A. \' lTCeccherelli, P.,Curini.M..E '8Ki., J. N.,Son,J. S.,l-ff. H lecu.ini,M., Rosati, O.,Pisar 2oJohn.on, P.,Taylor,R. J. K.

Potassium perman gansl,a Well-kr Oxidatians. assistance,ldispersion of kieselguhr.6

tvur.u, R. S.,Naicker,K. P l 'Hu.rir, \l'.. ! C. 8., Chrisman. (1997). sBenhaliliba, H., Derdour.A.. I aOussaid, A., Loupy,A. JCRIj

permanganate 315 Potassium

COOMe

,.

+

oxone@ NaHCO3

H2O - MeCN

r.': : -

OH

\''o:TcooMe t \-/

l

86Yo

Oxidation of nitrogenous compounds. Both ketoximesr3 and secondary niftoalkanesraare oxidized to ketones. Aldoximes are converted to nitroalkanes,l5 but niffiles are formed under different conditions.16In the presenceof a chlorine source(NaCl, HCI) ketoximes give c-chloronihoalkanesrT and nihoalkenes give the cr-chlorinated products.l8 The formation ofdiphenylmethyl estersrewhen benzophenonehydrazone is oxidized in the presenceof carboxylic acids most likely involves diphenyldiazomethaneas intermediate. Episulfones.2o Episulfones can be isolated when episulfides are oxidized with Oxone@-trifl uoroacetone. ri.:rhr des to acidsewith Oxone@ ,: (1-acetyl-Y-butyrolactoneto a:: :r. decarboxylation,and ring

559io

F.itherdiacids or the monoIl i.': , ,,nditions. ,

1,

-COOR

v Ycoon cr,rg

I

, r.r dioxiranes)occurs at the

tArrnrt.ong, A., Ahmed,G.,Garnett, I., Goacolou, K. SL 1075(1997). 'Armstrong, A., Draffan,A. G. St 646 (1998). 'Denmark,S.E., Wu, Z. JOC 63,2810(1998). -Yang, D., Yip, Y.-C.,Jiao,C.-S.,Wong,M.-K. JOC 63,8952(1998). ".Wang,Z.-X., Shi,Y . JOC 62,8622(199'7 ). ozhu,y., Tu,y., yu, H.,shi,y. 2a 39,7819(1998). 7song, C.8., Kim, Y. H., Lee,K. C.,Lee,S.,Jin,B. W. fA 8, 2g2l (lggi). nYang, D., Yip, Y.-C.,Tang,M.-W.,Wong,M.-K.,Cheung, K.-K. JOC63,9888(1998). 'Webb,K. S.,Ruszkay, S.J. I54, 40t (1998). r0Ragoussis, V., Lagouvardos, D. J.,Ragoussis, N. SC28, 4273(lgg8). "Ballini, R., Curini,M., Epifano,F.,Marcotullio, M. C.,Rosati,O. SZ 1149(1998). ''Yang,Y., Wong, M.-K.,Wang,X.-C.,Tang,Y.-C.JACS120,661I(1998). '-'Bose, D. S.,Srinivas, P.5C27,3835(1997). laCeccherelli, P.,Curini,M., Marcotullio, M. C.,Epifano.F.,Rosati,O. SC28,3057(1998). rsBose, D. S.,Vanajatha, G. SC28,4531(1998). 'oBose, D. S.,Narsaiah, A.y. TL 39,6533(199S). ''Ceccherelli, P.,Curini,M., Epifano,F.,Marcotullio, M. C.,Rosati,O. TL 39,4385( 1998). r8Ki., N., J. Son,J. S.,l,ee,H. J.,Jung,K. S. SC27, 1885(1997). tncu.ini, M., Rosati,O.,Pisani,8.,Cabri,W., Brusco,S.,Riscazzi, M. TL38, 1239(1gg7). 2oJohnron, P.,Taylor,R. J. K. ZI, 38,5873(1997).

Potassiumpermanganate.13,258-259;14,267;15,2'73-2'14;18,301;19,277-278 Oxi.dati.ons. Well-known oxidation processeshave been modified by ultrasound assistance,rdispersion of KMnOo on solid supports such as alumina,2-azeolite,5and kieselguhr.6 rva.-u, '7463 R. S..Naicker,K. P. Zt 39. OggS\. tHurrir, C. 8., Chrisman, W., Bickford,S. A., Lee,L. Y., Toneblanca, A. E.,Singaram, B. ?f 38,981 (r99't\. 3Benhaliliba, H., Derdour, A., Bazureau, F., Hamelin,J, TL39,541(1998). J.-P.,Texier-Boullet, -Oussaid, A., Loupy,A. JCR(S)342(199'7).

316

Pyridiniumdichromate

5sreekumar, R., Padmakumar, R. fL 38, 5143(lgg'1-). 6l-ou, J.-D.,tnu, W.-X.SC27,369i.(lgg7).

Potassium persulfate. Cleavage of N\thiophenyl)benzyl group.t The oxidative cleavage with KrSrO, in aqueous MeCN does not affect a BJactam ring; therefore, imines containing such can be used to condensewith ketenesto form p-lactam adducts. Dimethyl qc*alkanedicarboxylates.

o-Nitrocycloalkanones suffer ring scission on

Rhenium(VU) oxide. 17. I Epoxidation.l Ttre u

exposureto &SrO, in methanol containing sulfuric acid. The dimethyl estersare obtained.2

epoxidation catalyzed b1 R

Note the accessibility of or-formylcarboxylic esters by sequential treatment of with alcoholic KOH and KMnOo-MgSO, (Nef reaction).3 cx,-nitrocycloalkanones

tYrdin,

a\^ \

K O H / M e O HA ; KMnOa MgSOa

(f"oo"" \--cHo

Noz 77o/"

rKarupaiyan, K., Srirajan, V., Deshmukh, A. R. A. S.,Bhawal,B. M. 254, 4375(lgg8). 'Ballini,R.,Bosica, (1997). G.253, 16131 3Buuini,R.,Bosica,G.,Gigli,F. T 54,'7573 (1gg8).

Potassium superoxide-o-nitrobenzenesulfonyl chloride. Benzglic oxidatian. By this reagent combination in MeCN, benzyl ethers are oxidized to benzoic esters(11 examples,8l-93vo).t Arylacetic acids undergo oxidative decarboxylation which results in aromatic aldehydes( l0 examples. 52-84Vo).2 'Kir, y. H.,Kim,H. I., Kim,J.y.JCS(pt)633(1998). 'Kim, Y., Kim, Y. H. TL39,639(1998\.

Pyridinium dichromate. 14, 269 N-Aryloxazolidines. Many 1-(N-methylanilino)-2-alkanols unexpectedly give the oxazolidines in good yields on oxidation with PDC.

(-(o*"

*TIV o H l

A. K., Sharpless. K. B

Rhenyl trichloride, bis trl (El-crOlefination.t with ethyl diazoacetate'* hc lledford,

B. E., Carreira.E. \t.

Rhodium/alumina.

Hydrogenation.t Th tetrasubstitutedalkenesu hr Oxazolidines.2 Ther 1,2-aminoalcoholsand nim the presenceof 57o Rh/C.

rYamaguchi, M., Nitra,A.. R6d 'Letinnois, S.,Dumur.J.-C..l|r

Rhodium carbonyl clustcn Carbonylation The carbonylation method is t introduction ofa ketone si*

€{"

(pyH)2Cr2O7

cH2ct2

"T,o

Rhe(COr

891o

MeNt--NPY lYli-Kauhaluoma, J. T., Harwig, C W., Wentworth, P.,Janda, K.D. TL39,2269(1998).

:ll.1rc with KrStOr in suchcan be x':::.1lning oxide. 17, 296-297 ; 18' 305; 19, 280 The utility of bis(trimethylsilyl) peroxide is critical for the efficient Epoxidation.l epoxidation catalyzedby RerOt. Rhenium(Vll) .rlfcr ring scissionon l\. !.'tersareobtained.2 Ju.nriill treatment of ic::.'action).3

rYudin,A. K., Sharpless, K. B. 'IACS119,11536(1997).

COOMe ;F.3

Rhenyl trichloride, bis(triphenylphosphine) complex. (E;-o,B-Unsaturated esters are obtained from reaction of aldehydes olefination.t when catalyzed by (Ph,P)rReOClr. ethyl diazoacetate with

T.

rLedford,B. 8., Carreira,E. M. ?L 38, 8125(1997).

r:-< 1998).

Rhodium/alumina. The catalyst is particularly useful for the saturation of Hydrogenation,t are conjugated to a ketone group. which alkenes tetrasubstituted compounds are formed from mixtures of heterocyclic These oxazolidines.2 (17 89-997o) underhydrogenationconditionsin examples, nitriles 1,2-aminoalcoholsand

henzyl ethers are l\ rrj- undergooxidative

the presenceof 57o Rh/C.

.:l-S-17c)'2

rYamaguchi, M., Nitta,A., Reddy,R. S.,Hirama,M. sr 117(1997). 2letinnois.S..Dumur,J.-C.,Henin,F.,Muzart,J. TL39,232'7(1998).

Rhodium carbonyl clusters. 13,288; 15,334;18' 305-306; 19,280-281 The development of a 3-isochromanone synthesisr using the Carbonylation carbonylation method is the extension of some previous work. More unusual is the , re r.pectedlygive the

introduction of a ketone side chain to the piperazine system.2

lYo

A

SeO2/ PhH

protected,using EtOAc-\ Reaction of oximes.

H2SO4-SiO2under micror NH2OH.HCI, and HCOOI of ketonesfrom ketoxinre NalO! or NaBiDO; ro &

Silica gel. 15,2821'18, 3 I 9; 19, 303-304 Isomerizations. A facile l,3-rearrangement of an allylic phS group on silica gel chromatography transforms allylic alcohols into the homoallylic isomersl while bringing the functionalities closer together. on chromatography, the propargyl ketones obtained from the Dess*Martin periodinane oxidation are prone to isomerization to give the allenic ketones.cross-conjugated systemsare further susceptibleto Nazarov cyclization.2

o

tn.-A.

\./

sio 2

l l l l

fi

lG.iso.'euu,N. Y., Tsiklaun 2Hu;rni. A. s. K.. Bats.J \\ 3Nugurno, T.. o S.,Furukar+a. 45iro. G.. Martin.J..Gan-r J. tKurn-, H. M. S.,Reddl.B I oBenAlloum,A., Bakkas.S . TTanaka. \ .h Y., Sawamura.

Silica gel-supported rceg Adsrq Acetylntion. symmetricaldiols.' For g

\-".-Ci

'Emet,T., Haufe,G. S 953(1997). 'Singh, J.,Sharma,M., Kad,G. L., Chhabra,B. R. "/CR(S)2e OggT). 'Pansare, S. V., Malusare,M. G. SI 671(lgg7). -No, 2Z., Chae,Y. B., Shin,C. J.,Chung,Y. TL39,6l9t (1998).

periodinane Dess-Martin

Defunctionalizntion. tosyloxy group is not unus lactone3 when a strategica N-Boc groupsaby silica ge

Ph-.'\

\

/

Oxi^dations. GIycol and microwaveirradiatirrn same method seems to I titanium/tartaric acid caul hydrogen peroxide as the r

A percarboxylic acid. orthosilicateto aqueoused is hydrolyzed and treatedr Miscellaneous reactit

Friedel-Crafts reaction derivatization that introd

catalyzing Michael reacr supponedon silica gel br

'Ogunuu, H., Amano.I't.. Cht

Silica gel-suPPorted reagents

Defunctionalimtion' f i.1.5-thiadiazolidine

v/o

of a homobenzylic Aryt participation in the ionization

tosyloxygroupisnotunusual'Suchaphenoniumionintermediateisreadilyconvertedtoa lactone3whenastrategrcallylocatedesterispresentinthesamemolecule.Removalof of microwaves is an expedient method' N-Boc groupsaby silica gel with assistance Cond'ensationreactions.Thenitroaldolreactionsandformationofbenzimidazoles6 with are caried out in silica gel support from o-phenylenediamine and aldehydes microwaveirradiation.Thelatterpreparationalsoincludesnitrobenzeneordimethyl condensationproducts' sulfoxide for dehydrogenatingthe initial AcetalizationofcarbonylcompoundscanbeperformedwithamesoporouscatalystT preparedfrom colloidal silica and CtrHrr(Me),NBr'

,\o

: iuran derivatives bY ftrr r]taflYcases.Dienoic

'Grigor'"uu,N. Y., Tsiklauri'P' G ' Buevich'A V' MC 76 (1998)' -H" Schwarz' L TL39' 7491(1998)' zHashmi, A. S. K., Bats,J W', Choi'J 2849(1997)' 38' fL H' tNugu*o,S.,Furukawa, Akita' T'' Ono'M ' 147(1998)' aSiro,J.G.,Martin,J.,Cu"tu-Nluio'I L'Remuinan'M'J'Vaquero'JJ SL ( 1998)' 637 CL S tfu*ur, H. M. S.,Reddy,B V' S ' Yadav'J' 6B"neliourn,A., Bakkas,S'' Soufiaoui' M' TL39' 4481(1998)' tiunutu, Y., Sawamura, N ,Iwamoto'M' TL39' 9457(1998)'

II ,'-

. - -r\ '

n

Silica gel-suPPorted reagents' of gel enables selective monoacetylation Acetylation. eOsJrption on silica

-3

symmetricaldiols.'Forp'itury/'"tondarydiolpairsthelesshinderedalcoholgroupis as the reage.nt' protected,using EtOAc-NaHSOl or HC(OMe)t-LnCl] with dehydrated io afford nitriles on treatment Reaction of oximes. Aldoi.imes are H2So4-Sio2undermrcrowave.aActuallyitsufficestoirradiatethemixturesofaldehydes, NH2OH.HCI,andHCooHwithmicrowaveforthedirectaccesstonitriles'5Regeneration while adding wet achievedby the sametechnique' of ketonesfrom ketoximes is readily NalO! or NaBiDOl to drive the reactton' gel support can be improved using the silca Oxidations. Glycol cleavageby NaIOt Ph\ qroup on silica gel r\\\nr!'rsrwhile bringing F.r!\ I ketones obtained r2r:r\,nto give the allenic !',.r ;r, CliZati6n.2

-";---x

i ^.

o ph-*A

andmicrowaveirradiatlon.8Th"o*idutionofsulfidestoeithersulfoxidesorsulfonesbythe samemethodseemstobedependentonthedurationoftheirradiation.gSupported titanium,/tartaricacidcatalystiSsuitablefortheconversionofsulfidestosulfoxidesusing hydrogenperoxideas the main oxidant'r0 Apercarboxylicacid'preparedbyadding2.cyanoethyltriethoxysilaneandtetraethyl silica which I -dodecylamineto give a cyanated orthosilicateto aqueousettranotcontaining rI agent MsOH' is a useful epoxidizing is hydrolyzedand treatedwith HrO, and gel the silica and. tvtediated Uy grounded FeCl't Miscellnneous reactions' F r i e d e l - C r a f t s r e a c t i o n o f a r e n e s w i t h ' l r C C t ' t p r o v i d e s b e n z o p h e n ouseful n e s ' r for 2After pendants the silica.is derivatization that introduces dimethylaminopropyl catalyzingMichaelreactions.l3Alcoholsareattachedtocarboxylicacidswhichare supportedon silica gel by esterification''" togu*u, H., Amano,M', Chihara' T' CC495(1998)'

340

Silver nitrate

2Breton, G.W. JOC 62,8952 (lgg7). 3Biun"o, A., Melchioni, C., Romagnoli, P. ZL 38, 651 (1997). tKu.ur, H. M. S., Mohanty, P. K., Kumar, M. S., Yadav, J. S. SC 27, 1327 (199'1). sFeng, J.-C.,Liu, B., Bian, N.-S. SC 28, 3765 (1998). ovarma, R. S., Dahiya, R., Saini, R. K. fZ 38, 8819 (1997). 7Mit u, A. K., De, A., Karchaudhuri,N. Sl, 1345 (1998). ozhong, Y.-L., Shing, T. K. M. JOC 62,2622 (199'7). 'Varma, R. S., Saini, R. K., Meshram, H. M. ZL 38, 6525 (1997). rOFraile, J. M., Garcia,J.l.,Lazaro, B., Mayoral, J. A. CC 1807 (1998)' rrElings, J. A., Ait-Meddour, R., Clark, J. H., Macquarrie,D. J. CC270'7 (1998)''Khadilkar, B. M., Borkar, S. D. 24 38, 164l (199'7). 13Mdo", J. E. G., Clark, J. H., Macquarrie,D. J. SL 625 (1998). 'odu G.u.u Nasscimento, M., Zanotto, S. P., Scremein, M., Rezende,M. C. SC 26' 2'715(1996).

Silverfi)oxide.18,321 Protection of alc ohols.' benzylationusingAg"O asb

rBouzide, A., Sauve,G. fL 3t. :

Silver perchlorate.16,]CX Transannular cYclizoi in the caseof a macrobicl'c dependingon thereactiontc

Silver carbonate/celite.18, 320 addto of AgCOr/celite I,3-dicarbonylcompounds Cycloadditions. In thepresence include The alkenes various electron-richalkenesto form dihydrofuranderivatives. andenolethers.3 alkenylsulfides,2 l ,1-dialkylalkenes,r

ETOOC\ I zAO

+

\ rl-gp6

Ag2COsCelite MeCN

Agd THF

EIOOC.._--1

60"/"

ll FsPn ./-ci tKuto,

Silver trifl uoroacetateOrthocarbonales.t I anchor to gather four alb spirocycliccomPounds.

rLee.Y. R.,Kim, B. S. TL38,2095(1997). 2l-ee.Y. R.,Kim, N. S.,Kim, B. S. ?L 38, 5671(199't). 3lee,Y. R., Kim, B. S.,Wang,H. C. T 54,12215(1998)

Silver nitrate. 18,320; 19, 305-306 N-Acyloxazolidinones can be cleaved by EISK. Thioester that is part Deacylation.t of a 1,3-dicarbonyl system undergoes C-C bond cleavage on exposure to AgNO.,-2,6-lutidinein aqueousTHF.

i l l Y

N -An t'n

T., Tanaka, M.' Ho6hlt

EISK;

fa\-o" V-o" OH

AgNO3 / 2,6-lutidine

NHPh

aq.THF 99%

rEvans, D. A., Ripin, D. H. B., Johnson,J. S., Shaughnessy,E.A. ACIEES6'2119 (1997).

C-Glycosylation.- I alkl le Friedel-Crafts-tYPe

Silver trif luoroacetate

-(, :- t -.r:7( 1997).

341

Silver0) oxide. 18, 321 Symmetrical diols are maskedat one site by such method as Protection of alcohols,r as base. benzylation using AgrO lBouzide.A., Sauve,G. ?L 38, 5945(199'1).

(

-, : r- t I 998).

Silver perchlorate. 16' 300-301; 18,321-322 The silver salt assistsionization of allylic chlorides and Transannular cyclization.t in the case of a macrobicyclic triene the exposure leads to formation of one or two rings, depending on the reaction temperature.

c-

. \r c.sc26, 2715(1996).

i i-Jrcarbonylcompoundsadd to dc::. rtives. The alkenes include

AgClOa

AgClOa + THF - 2OO

I:OOC.,a ll )-sPh a"-ci

THF 2OO

60%

'Kuto,

T., Tanaka,M., Hoshikawa,M', Yagi, M. 71 38' 7553 (1998)'

Silver trifl uoroacetate. orthocarbonates.t when activatedby cFrcooAg, carbondisulfideprovidesan anchorto gatherfour alkoxy groups from alcohols.Amino alcoholsform analogous spirocycliccompounds.

r -.: .r EISK. Thioester that is part )c.: ileavage on exPosure to

ri\ro" \zLot

AgOCOCF3 +

cs2 - Er3N

G}"D

MECN

ro*

,'t

-NHPh

AgOCOCF3 D cs2 - Et3N MeCN

\

I r /t-.f J6, 2119 (1997).

c-Glycosylation.2 A combinationof cFrcooAg andSnCloeffectivelypromotesthe alkylationof activatedareneswith glycosylesters' Friedel-Crafts-type

342

Sodium

R

'Shibuyu, I., Gama, Y., Shimizu,M. H 48,461 (1993). 'Kuribayashi, T., Ohkama,N., Satoh,S. TL39,453'7,4541 (tggS\.

n"ruA

\_c

Silver trifluoromethanesulfonate.13,274-275; 14, 282-283;16,302;t7 ,314: 18, 322-323;19,306 Allylation. Carbamatesof 2-Allyl-1,2-dihydroquinolineand the isoquinoline analogsare formed by the catalyzedreactionof the heteroaromatic compoundswith CICOOR and allyltrimethylsilaner(also alkynylation2).Heterocyclizationof isonitriles containingan allylsilanemoiety,initiatedby C-acylation,is promotedby AgOTf.3

'.siHres

a> **.--,J

d,"",

tshi,2.,Gu,H. sc 27.270 2Yu,Z.,verkade, J. G. It i 3R"ddy,G. v., Iyengar.D I

Sodium amalgam. l& I Ar Deuteration.t is by ffeatrnent of halides

t-BuCOCl /CH2CI2:' AgOTI

SiMe3 82%

'Yamaguchi, R.,Hatano,B., Nakayasu, T., Kozima,S. 7L 38, 4O3(lggi). 'Yamaguchi, R.,Omoto,Y., Miyake,M., Kozima,S. CL 547(1998). 'Kercher, T., Livinghouse, T. JOC62,805(1997).

rMiura,Y., Oka,H., Yarnr

Sodium-ammonia. lG C-S bond scissiot

example, benzothioPhc ammonia. Acyloin condengi glasspowder,polyethl I

competentemployment Sodamide. Amides or alkenes.t Mannich salts undergo fragmentation on reaction with sodamide. The major products obtained from the salts derived from ketones are primary amides, but those derived from aldehydesare alkenes. tMol..

D.. Risch.N. I-4,1765(lggi\.

Sodium. 13, 27'l ; 18, 323-324 RCOOH -+ RCHO. 2-Substituted imidazolines prepared from acids and ethylenediamine in hot toluene are reduced by Na in ethanol to the imidazolidines. Acid hydrolysis of the latter affords aldehydes.r Desulfurizntion. sulfides are converted to alkane fragments2on heating with Na in an inert solvent at high temperatures.Conversion of phenyl styryl sulfone to styrenein 957o yield indicates that double bonds are not affected. Cleavageof oxazolidines.r A route to o-substituted allyl amines starts from N-acetyl cx-amino acids via the oxazolidinones. The latter compounds are converted to dichloromethylene derivatives by reaction with P\P-cclo and the final step involves dechlorination and ring opening (and removal of an HCo unit) with Na in refluxing THF.

lYu,2.,Verkade, J.G. Ps tMukorru,M., Grela.K- 5l

Sodium azide. lE, 325l,2-Azido alcohols hydroperoxides on irrad (e.g., rhodamine B) in furnishes the azido alco Azides.z

Benzl b

system. Other aliphauc

tn\A I OH

rGriesback, A. G.,Hun&

2Kuma., H. M. S., Red{.

Sodiumazide

^.1;{.,

343

Na / THF

r,- l

-.

.rl{: 18,

HN)V Ac 61 - 72%

o.: ::c

rsoquinoline u:- ,,'nrpoundswith hr":. ,n rrf isonitriles | ..

\rOTf.r

'shi, 2., cu, H. sc 27.2701figgr. 2Y u, 2' y erkade, I. G. TL 39, 26'71 (1gg8'). 3R"ddy, c. V., Iyengar,D. S. Ct t23'7(tgg8).

Sodium amalgam. 18, 324; 19, 306 Deuteratian.t A convenient intoduction of deuterium atoms into organic compounds is by treahnentof halideswittr NaAIg in refluxing MeOD (17 examples,74-98%).

l

/-

SiMe3

rMiura, Y., Oka,H., Yamano,8., Morita,M. JoC 62,11880997). Sodium-ammonia. I 6, 303-3 04 ; 18, 324; 19, 306 -307 C-S bond scission,\ Selective reductive bond scission is accomplished. For example, benzothiopheneis converted to o-ethylbenzenethiol(99Vo) by Na in liquid ammonia. Acylain condensation.' Sodiurn deposited on a solid support which can be NaCl, glasspowder,polyethylene,or polypropylene,is easilypreparedin liquid ammonia.It finds competentemploymentin acyloin condensation.

. :. rcactlon with t.'

:tc\ are primary

rYu,2., Verkade, J. c. PSS133.79 (1998). 'Mukorru, M., Grela,K. SL 267( 1997);Makosza, M., Nieczypor, P.,Grela,K. I 54, 10827( 1998).

Sodium azide. 18, 325-326;19,307 l,2-Azido alcohols,r Alkenes

are functionalized give to cis-|,Z-azido hydroperoxides on irradiation with Na\ under oxygen in the presenceof a photosensitizer (e.g., rhodamine B) in an aqueous medium. Reduction of the produc(s) with LiAlFl f: ::: acids and rlidines.Acid r: -:.:zr hr.:illt{ with Na in r : .rr renein 957c

furnishes the azido alcohois. Azides.2 Benzylic and allylic alcohols are convertedto azidesby the Na\-BF3.OEI2 system. Other aliphatic alcohols do not undergo this transformation.

tnY*ot

t:- :::luxing THF.

PhvlvoH I

OH n::i. \tarts from s .r:r .onverted to i:.., .rep involves

NaN3- BF3.OEI2

N3 847"

I Griesback, A. G., Hundertmark, T., Steinwascher,J. TL 37, 836'1(1996). 'Kumar, H. M. S., Reddy,B. V. S., Anjaneyulu,S., Yadav, J. S. ZZ 39,7385 (1998).

Y4

Sodiun borohydride

Sodiumbismuthate. Aryl ketones.t Benzylic oxidation is convenientlycarriedout with NaBiO. and aceticacidin aqueousacetone. tBanik,

B. K., Venkatraman, M. S., Mukhopadhyay, C., Becker, F. F. fL39,7247

(lgg8).

Sodium borohydride. 13, 278-27 9; 15, 290; 16, 304;.lE, 326-327 ; 19, 307 -309 A method for the conversion of dicarboxylic acids to Esterreduction. ohydroxycarboxylic acids involves formation and reduction (with NaBH) of dilactonesin which the two carbonyl residuesare linked by an OCH'O chain.t Arylpyruvic esterscan be reducedto either the a-hydroxyestersor |,2-diols.2

O\,.O - O z.o t r I

OH

I

\ l la r -H

OH | tnaA"oor

# I

H ----- l | COOMe I

/\ Ll--Mn(co)s

Ph'

6so/"

The subsequent reduction is carried out with NaBH, in methanol. Oximes of cr-aminocycloalkanones undergo fragmentation and reduction, fumishing co-amino nitriles.6 A route to substituted ureasTinvolves reductive alkylation, condensation with aldehydesin the presenceof Me,SiCl followed by treatrnentwith NaBH4. The borohydride reduction of p-amino-a,p-unsaturatedestersin the presenceof isobutanoic acid8 may also proceed via iminium species.

o

PhMgCl

"

Chiral oxazolidones are readily preparedr from carbamates of c-amino esters by reduction with NaBHo-LiI in refluxing THF. Note that imides (N-acyloxazolidinones) are reducedto alcohols, therefore the reduction representsa method for recovery of both chiral products and auxiliaries.a l,3-Diamines can be elaborated via reduction of the Reductionof iminiumsalts. monoiminium speciesswhich arise from condensationof enamineswith aldiminium salts.

tn.""o

PFa

-.^, "-'o

OH I PhvvoH

I NaBH4> EIOH

*

I

Solventeffectsin r.h ln of NaBHois increased.r( promotesgenerationof thc

F 92o/o

"ttyttt

ao) (*/

NaBHa

\.,/

o | Ph,/z\

Reduction of cationic t

hexenones from the morPho reactivation with NOPF.. h in MeCN. The preParation< secondnucleophiles other d

HOAo/ Me3SiCl; +

NaBH4

H P h N

\,/ V ll o 600/"

NHz

Hydrodebrominatiot

corresponding tin iodide tr: in the presence of AIBN

m

lBenitez,P., Delgado.A.. Ft 'Dullu. v., cotelle, P., Cancl 'Sudhu.rh*, M., Hultin P. ( aPrashad,M., Har, D., Kirt I sMerla, B., Arend, M.. Risci, oPetukhov,P. A., Tkachcr. I 7Xu, D., Ciszewski,L.. Lr. T 8Xu, D., Prasad,K., Repic.O gP"u.ron, A. J., Vickernran I loYang, C., Pittman,C. L. 5C t'Barror, M. T., Maycat- C, l2Dumartin, G.. Pourcel. I{.. I

345

SodiumborohYdride

Du: \\ith NaBiO,

and

-1.r,i 1998).

: 19. .r07-309 ra*xrxylic acids to laBH. I of dilactonesin ripr rur'ic esterscan be

,'OH

Reduction of cati.onic metal complexes.e A route to 5-substituted 2-cyclo' hexenonesfrom the morpholinobenzene-Mn(CO), complex involves a Grignard reaction, reactivation with NOPF., borohydride reduction and hydrolytic decomplexation with HCI in MeCN. The preparation of more highly substitutedcyclohexenonesby finding suitable secondnucleophiles other than NaBHo has to be tealized.

Q I

o ,\

PF"

t i l Ph"'\/

@r.,"o,

68% overall

in diglymethe reductionpower Solventeffectsin reductions. At high temperature of epibatidinethe additionof DMSO In thecontextof a synthesis of NaBH, is increased.lo alcohol.rI of the desiredsecondary promotesgeneration 7 1"/"

cl--/N-\ oH i l | | \/",,,//\

),.Je NaBH4

.

DMSO- MeOH - 200

F.

OTBS

t

l

\-,/ : Oras

(62 : 26)

ot c-amino esters by cr .,'razolidinones)are r..r\r ery of both chiral d rra reductionof the s rlh aldiminium salts. Nrhrnol. Oximes of rurnishing o)-amino on. .ondensationwith Ell. The borohydride u:rni)lc acidsmay also

')/ NHz l U

96% totalyield

Generation of a polymer-supported tin hydride from the Hydrodebromination.t2 correspondingtin iodide with NaBHo for the reduction of I -bromoadamantane(93Voyield) in the presenceof AIBN minimizesorganotincontaminants' P.,Delgado,A., Farrera,J.-A.,Ribo,J. M. SC27, 16972(199'7\. ^rBenitez, 'Dalla, V., Cotelle,P.,Catteau,J. P. IL 38, 15'7'7 (1997). 3sudharshan, M.. Hultin,P. G. SL 171(1997). aPrashad, M., Har,D., Kim, H.-Y.,Repic,O. TL39,'7067(1998). 5Merla,B., Arend,M., Risch,N. SL l'77(199'7). 6P"tukhou. P. A.. Tkachev.A. V. I53, 2535(199'7). 7Xu,D., Ciszewski, T. J. TL39' 1107(1998). L., Li, T., Repic,O.,Blacklock, 8Xu,D., Prasad,K., Repic,O., Blacklock,T. J. fA 8, 1445(199'7). eP"urrorr, A. J.,Vickerman,R. J. fZ 39, 5931(1998). roYang,C., Pittman,C. U. SC28, 202'l (1998). llBunos,M. T., Maycock,C. D., Ventura, M. R. TL 40,557(1999). r2Dumartin, M. TL39,4663(1998)' B., Donard,O.,Pereyre, M., Delmond, G.,Pourcel,

:-at"

:l

346

Sodiumborohydride-nickelsalt

Sodium borohydride-antimony. ArNOz-+ATNHOH,I While a previous report indicates that reduction of nitroarenes with the combination of NaBHo and SbCl, leads to arylamines, the antimony-catalyzedreduction gives N-arylhydroxylamines (5 examples, 73-88Va).

(Z,E)-l,3-Dicnol ahqt reduction with NaBH"-Nit C

rRen,P., Dong,T., Wu, S. SC27, 1547(lgg7).

Sodium borohydride-iodine.

17, 3 16; 18, 328; 19, 309 Cleavage of allyl ethers.t This systemservesto remove O-allyl groups in THF at 0" without affecting other ethers such as THP, TBS, benzyl derivatives. Coniugate reduction.2 Conjugated dienamides undergo regioselective reduction with the borohydride iodine system in THF ar 0o at one of the double bonds, forming y,6-unsaturatedamides. 'Thornur, R. M., Mohan,G. H., Iyengar, D. S. ZL 38, 4.l2t(lggi). 2Das, B., Kashinatham, A., Madhusudhan,P. TL39,6i'j (lgg$.

Sodium borohydride-nickel

salt. Cleavageof aziridines.t Aziridine-2-c:rboxylic esters undergo ring opening to afford B-aminoesters.Accordingly,this regioselectiveC-N bond cleavageis crucial to the indirect but more efficient Michael reaction for the synthesisof B-amino acids.

Ph--N -cooEt

rsil>

N a B H a- N i C l2

.....................*

Ph"'vcooEt I NHTs

MeOH

95% NaBHa- NiCl,

rs(\co6t' Ph

-

H

MeoH

L

T5N/\.COOEI

'

Ph

.Y"\ Y""en lDauban,P., Dodd,R. H. fL t tBu.ton, D. H. R.,Liu. W. It I

Sodium borohydride-titr ' Secondary amines.' MeNHr.HCl is easily accorq 'N"idigh,K. A., Avery,M. A.l

Sodium bromate. lE. 3-30 Bromination.t Select system is reported. In aqueo nuclear bromination predorn

Oxidations. Seconda by NaBrO,-NHrCl in aqu oxidation is sensitive to soh, profi le, affording o-diketonc

9Oo/"

Amides.z The intermediatesfor a two-carbon homologation via the Barton estersby photochemical decomposition in the presence of acrylamide need to be defunctionalized. Removal of the pyridylthio group is achievedby the nickel-mediated borohydride reduction.

OH OH

rd{# O".-"'*" O^"Q#ffiO

'Kikuchi, D., Sakaguchi. S..Istu 'shaabani,A., Ameri, M. JCR'S ''Sakaguchi, S.,Kikuchi.D.. lstu

Sodiumbromate

r e d u c t i o no f !-:rat l. :,' arylamines, the --l-887o). p r.

(Z,E)-1,3-Dienolethers' Thesecompounds reductionwith NaBHo-Ni(OAc)r.

ar^--/O-:--

l 1 l : r\)upsin THF at 0'

U''*\z-"

are available from

NaBH4- Ni(oAc)"

-;-

s

enynyl

347

ethers by

(

Jt:

r : .:lcctive reduction d ^ic honds, forming 'Dauban. P..Dodd.R. H. 7L 39,5739(1998). 2Button.D. H. R.. Liu. W. ZL 38, 2431(199'7).

rrng openlng to lc.:..:Lcis crucialto the u : r ; ' :' l c t d s . h:-

\, :ooEt t.*-s

:: \

tooEt

isopropoxide. Sodium borohydride-titanium(IV) The reductive amination of carbonyl compounds with Secondnry amines.t MeNHr.HCl is easily accomplished.Triethylamine is presentin the reaction mixture. rN"idigh,K. A., Avery,M. A., Williamson, S. JCS(P1I2527(1998)' J. S.,Bhattacharyya'

Sodium bromate. 18,330 Selectivebromination of alkylbenzenesusing the NaBrO,-NaHSO, Bromination.t system is reported. In aqueousEtOAc, benzylic bromination occurs, but in aqueousMeCN nuclear bromination predominates. Oxidati.ons, Secondary and benzylic alcohols are oxidized to carbonyl compounds but the by NaBrOr-NH,,Cl in aqueousMeCN.2 l,2-Diols are converted to cx,-ketols, product the changes oxidation is sensitive to solvents.3Thus, addition of dichloromethane profi le, affording cr-diketones.

\:.: :he Bafion estersby : \' defunctionalized. t ,: ,hrdride reduction.

OH OH cH2cl2

-y,^\-.CONH,

.2 1 000

lKikuchi,D., Sakaguchi, S.,Ishii,Y. JOC 63,6023(1998). 2shaabani, 100(1998). A., Ameri,M. "ICR(S.) 3Sakaguchi, S.,Kikuchi,D., Ishii,Y. BCSJ70,2561(199"1)

aYo \-Ao

348

Sodium(cyclopentadienyl)tricarbonylmolybdate

Sodium chlorite. Guanidines.t A synthesis of guanidines from thioureas features reaction with amines which is promoted by NaClO, (9 examples, 53-80%).

Sodium2-ethylhexanoate. Amideformation.t In thc is a usefulscaven BuCH(EI)COONa

Chlorination.2 Activated arenes are chlorinated with (salen)manganese(III)complex, and moist alumina in dichloromethane.

lFitt,

NaClO,

rRamadas, K., Janarthanan, N., Pritha,R. SL 1053(1997). 2Hi.ano, Yakabe, Monobe,H., Morimoto,T. M., S., CJC75,1905(1997).

Sodium cyanoborohydride-tributyltin chloride. 19, 3 l I Radical cyctization and reduction,t Tetrahydrofuran derivatives are formed when mixed allylic acetals of bromoacetone are treated with NaBH.CN-Bu.SnH (AIBN).

J.,Prasad,K., Repic,O., BlactlaL I

Sodium hexamethyldisilazide. l& -li Aryl cyanides.r Aromaric esrcr in the presenceof 1,3-dimethylimidrt Bridged rnr Wittig reactians.2 olefination with various aldehvdes.

Cyclization as well as dealkoxylation occur. 1Ph

\ -NMe --R.--.

M-1 eN/ \

/ \

Bu3SnCl- NaBH3CN AIBN/ I-BUOH

-itrr,rA \ /

\r.f-)

/

lHwu, J. R., Hsu, C. H., Wong, F. F.. Clrt "W ang,2., Verkade, J. G. TL 39. 93-1I r l9 'Srikrishna, A., Viswajanani,R., Yelamaggad,C. V. 253, lO4'79(1997).

Sodiumcyanoborohydride-trimethylsilylchloride. 19,3 I I Reductions.t While aryl aldehydes andketonesarereducedto thebenzylicalcohols, 2-acylbenzofurans andtheir acetalsundergodeoxygenation.

Sodiumhexanitrocobaltah(m ). Nilrosation,r This rcagenr 1,3-diaryltriazenes. Hydrazidesgir e r ArN=NNHAI. tSt"fune,

CHO

B., Kocevar, M., Polarrc.S. ./oC

Me3SiCl- NaBH3CN MeCN

'Box,V. P.C. TL39,7059(1998). G. S.,Meleties,

Sodium hydride. 14, 288; 16, 307--1 Cyclizatians, Cyclization of isomerization to the corresponding r acceptors.Access to the indolizidrrr 5-tosyl-4-pentenamideand subseqln A synthesisof resorcinolsl from & involves a Michael reaction-Dieckrnr

Sodium (cyclopentadienyl)tricarbonylmolybdate. Pauson-Khandreactions.t This salt Na[CpMo(CO),] converts alkynedicobalthexacarbonyl complexes into mixed Co-Mo analogs which often show higher reactivities in the cyclopentenonesynthesis. rRutherford, D. T., Christie,S.D. R. ZI 39,9805(1998).

rslYr trt{

l|

Sodium hydride

l!ur!'. reaction with r::i:

NaClO,

Sodium 2-ethylhexanoate. In the acylation of Amide formatian.t scavengerfor HCl. is a useful BuCHGt)COONa

amines

with

acid

chlorides,

rFitt,J.,Prasad, T.J. TL39' 6991(1998)' K., Repic,O.,Blacklock,

r Sodium hexamethyldisilazide. 18, 332 Aryl cyanid.es.l Aromatic estersare converted to nitriles by reaction with NaHMDS in the presenceof 1,3-dimethylimidazolidinone at 110oin a sealedtube' (E)-selective wittig reactions.2 Bridged triaminophosphonium salts participate in ,c. .rrc formed when \-Uu.SnH (AIBN).

olefination with various aldehydes.

,(tn

- o

MeN"-'\\Nlvle / 95%

lNirhiyu.u, T., Esumi, T., Iwabuchi, Y., Irie, H., Hatakeyama,S. ?4 39,43 (1998). 'Shibuya, A., Pietz, S., Taguchi, T. TL38,5537 (1991).

rAbdel-Magid, (1998). 2Vannelle,

A. t

P., Tem

Tetrabutylamr Cleavageof b1 accomplished lAkui,

s., Nishino.

Tetrabutylanmonium nitrite 3coutu.", A., Cornet, H., Deniau, 8., Grandclaudon' P., Lebrun, S. JCS(P1) 469 (1997)' 4Albanese.D.. Landini, D., Penso,M'.IOC 63,9587 (1998)' 5Kang, S.-K., Kim, T.-H., Fyun, S.-J.JCS(P1)'79'7(199'l)' 6UutJufturfti, H., Asai, S., Hirabayashi, K., Hatanaka, Y', Mori, A', Hiyama' T ' BCSJ 70' 43'1(1997)' ?Fugami, K., Ohnuma, S., Kameyama, M.' Saotome' T , Kosugi, M' S' 63 (1999)' oMolina,P., Aller, E., Lorenzo,A. S 283 (1998). eRod.igu"r, G., Castedo,L., Dominguez,D.' Saa,C. ?' 39' 6551 (1998)' roJoneslG.B.,Wright, J. M., Rush,T. M., Plourde,G. W', Kelton, T' F', Mathews'J E'' Huber' R S '

84"/"

Davidson,I.P. JOC 62,9379 (1998).

o:her halides by reaction with n.t ir\nes by homocouPlingof :r.rmples, 7l-94%o).s The 'I::::l uorosilanesrequiresexcess

Tetrabutylammonium hydrogen difl uoride. BurNHF, is a convenient sourceof nucleophilic fluoride which can be Fluorination. exchange in the used to displace groups such as NQ of4-nitrobenzonitrile.l For halogen an activator'2 is pyridine aliphatic series with BuoNHF,

:r.::.,ted.Thus, biarYl formation tg .tl()\ane in the presenceof {F ,1.; -+'7270yield).7

rAdu.r, D. J.,Clark,J. H., Nightingale,D' J. SC28, 4295(1998)' zMoughamir, C' TL39' 7305(1998)' C', Francesch' H', Rolando, K., Atmani,A., Mestdagh,

;s :rr .phosphoranylimino)cinnai:: R\=C=O. TBAF promotes ou- :n.rzolinederivatives.Cyclic I', , ,.\ cSan alkenylsilaneand an

Tetrabutylammonium hYdroxide. Hydrolysis of polypeptide esters.t

BuoNOH is useful for hydrolysis with minimum

racemization. to 2,3_Dialkytanthraquinones.2 A two-step annulation of l,4-naphthoquinone a and (HCHO, HCI) provide 2,3-dialkylanthraquinones involves bischloromethylation in BqNOH of presence the photoinduced reaction of the products with nitroalkanes in degassedtoluene(7 examples,5l-70%;o).

o ll

'l0o/o

n

)n',nlr'\esare decomposedbY

a\

(YY =r^)r* o

cl /'\|

R

*

\-Noe

BU4NOH H2O - PhMe NV

TYATYR \.ff* o 51 - 7O7o

rAbdel-Magid,A.F.,Cohen,J.H.,Maryanoff,C A,Shah,R D''Villani'F'J''Zhang'F'TL39'3391 (1998). 'Vunnill", P.,Terme,T., Maldonado, J.,Crozet,M P', Giraud,L' SL 1067(1998)'

\:// > 95Vo

l-1-1e.-13(1998).

Tetrabutylammonium nitrite. from the carbamates is cleavageof N-phenylcarbamates.t Recovery of alcohols accomplished by treatment with BurNNOr-AcrO' rAkai.S..Nishino,N., Iwata,Y., Hiyama'J.,Kawashima, E', Sato'K'' Ishido'Y'TL39' 5583(1998)'

Tetraethvlammonium trichloride

Tetrachf orosilane. 19. 323 Aldol reactions. Chalconesare formed by exposing aryl methyl ketones to SiClo in ethanol.l With Hg(OAc), as catalyst trimethylsilyl enol ethers are converted by SiClo to trichlorosilyl derivatives2at room temperaturewhich are useful donors in aldol reactions.

Tetrafluorosilane. Arylfluorides.' De.r.,, presenceof SiFoprovidesar but terminatedb1 temperature lTu.uru,

OSiMea "

SiCl4- Hg(OAc)2

osic13

-;;=

73./" Removal of N-t-butoxycarbonyl groups.3 In solid-phasepeptide synthesisan amino group can be releasedfrom N-Boc derivative by treatment with SiClo-PhOH.

M., Shibakami. M.. S€b,

Tetrakis(dimethylaminofrhl qa-Difluoroketones.: I chlorodifluoromethylketone. readily. aldehydes

rEl.o.ry, S. S.,Khalil, A. G. M., Girges,M. M., Salama,T. A. ./CR(S.) 232(1997). 'Denmark,S.E.,Stavenger, P.A. JOC63,9517( 1998). R. A., Winter,S.B. D., Wong,K.-T.,Barsanti, 3Sivanandaiah, B.P. TL37,5989(1996). K. M., Suresh Babu,V. V., Gangadehar,

Tetracyanoethylene. 19, 323 Esterification and transesterification.t

Tetracyanoethyleneused at about lO mol%o is the first fi-acid catalyst for esterification of carboxylic acids with various alcohols. Transesterification requires higher temperature. rMasaki,Y., Tanaka,N., Miura,T. CL55 (199'].).

rBurkholder. C.. Dolbier. !\'. R . \l

Tetraethylammonium hydrogen carbonate. Carbamates.t Amines are converted to carbamatesby reaction with Et NHCO, in MeCN at room temperaturefollowed by addition of alkyl halides (l I examples, 53-977o)' rlnesi,A., Mucciante, V., Rossi,L. JOC 63,1337(1998).

Tetraethylammonium trichloride. t This reagent is stable and easy to handle. lt can be Chlnrinationandoxidation used to introduce chlorine atoms to C-2 of 2-substituted 1,3-dioxolanes,the o,-position of aldehydesbesides alkenes and alkynes. Oxidation of alcohols such as benzyl alcohol and cyclooctanolin MeCN requirespyridine-DABCO (4: 1) as acid scavenger.

Tetrakis(triphenoxyphcpt$r Reduction.l The srable (to compounds alcohols).sulfa

amines) with ammonium fornu Heck reaction.) This ru catalystsfor the Heck reactiofl conditions.

o

d\i* t t l

\

Et4NCt3

-/

cH2ct2 -7go 88"/"

tschla.a,

T., Gabriel, K., Gouvemeur, V., Mioskowski , C. ACIEE 36,2342 (1997)

-:l llyer, S., Sattar,A. K. SC 2t. l 'lyer, S., Ramesh,C., Ramanr.A i

Tetrakis(triphenoxyphosphine)nickel(0)

rr'::r I ketonesto SiCloin a:: ,,,n\ertedbY SiCloto 1.r.,':. in aldol reactions.

Tetrafluorosilane. Deamination of aryl amines by treatment with t-BuONO in the ArylJtuorides.r pfesence oi siF4 provides aryl fluorides. The reaction is initially carried out at room temperaturebut terminated by heating to 130-140'. rTu.u.u, M., Shibakami, M., Sekiya,A. EJOC725(1998).

J>rur?

-

Tetrakis(dimethylamino)ethylene. Enolates of Cx,Cr-difluofoketonesare generated from q,A-Difluoroketones,l on treatment with the reagent 1' These enolates react with ketones chlorodifluoromethyl

j ' ,

anamino F I rJesynthesis S : ( -PhoH. ::_

. ) 9 7) .

a : i

\ /oc63,9s17(1998).

aldehydesreadily.

c96 ).

:.cd at about 10 molTo .rirh various alcohols.

td

Me2N. - \

/NMez

Me2N

NMe2

(1)

rBurkholder, Dolbier, W. R, Medebielle,M., Ndedi, A. TL39' 8853 (1998)' C.,

ftsJ,::\)n with EI4NHCO, in I r'xamPles,53-91Vo).

.-

Tetrakis(triphenoxyphosphine)nickel(0). The stable Ni(0) complex is a useful catalyst for reduction of carbonyl Reduction.t (to compounds(to alcohols),sulfonyl azides(to sulfonamides),iminesand nitro compounds amines) with ammonium formate. t Thi. nickel complex offers an altemative to the many palladium Heck reactinn reaction catalystsfor the Heck reaction.Alkynes also react with aryl iodides under the same

d J.r.\ lo handle. It can be i. '. ..rncs,the cr-positionof .-. . .r\ benzylalcoholand d .,.rr c'n$€r.

conditions.

o

o

Z\A^rv" a

\-\

(Pho)3Pl4Ni + K2CO3

\

il

NMP

al

:3'. I r1997).

rlyer,S., Sattar,A. K. SC28, l'721(1998). 2lyer,S.,Ramesh, C.,Ramani,A. fL 38,8533(1997).

ZlArurr,r"

\,V I

79"k

362

Tetrakis(triphenylphosphine)palladium(0)

Tetrakis(triphenylphosphine)paltadium(0). 13, 289-294; 14, 295 -299 ; 15' 300-304; 16, 3 17 -323 ; 17, 327 -33 1; 18, 347-3 49 ; 19, 324-33 1 carboxylic acids are reduced to aldehydes by hydrogen in the Hydrogenation.t presenceof (PhrP)oPdand pivalic anhydride. Alkenoic acids (oleic acid, erucic acid) give unsaturatedaldehydes.Diacids are similarly reduced. Sulfinic acids or their sodium salts assist Allyl and propargyl group transfer. Pd(0)-catalyzed deallylation by accepting the allyl group.2 In addition to allylic esters, allylic sulfoximines can also deliver the allyl group to nucleophiles such as amines.3 Acrolein acetalsreact with 1,3-dicarbonyl compoundsbut the regiochemistry is strongly dependenton reactiontemperatures.4

O (Ph3P)4Pd

I

o

tl

OMe

( Y + \-t,Ao

ueoM

rHF 40"

^

THF 4OO; go- 11oo

VoMptr

o

L>'/t l

OMe

\v,\o

Ph

70/"(E:Z83:'l7l

Distributive addition to benzylidenemalononitrile occurs when the decomposition of allyl B-oxoalkanoatessor carbonates6is canied out in its presence.The counteranionsof the initially formed n-allylpalladium salts are not stable so that the nucleophilic addendsare the decarboxylated species. The reaction with vinyloxiranes generates tetrahydrofuran derivatives.T

Ph Ph \

C

N

Y CN

"t'a: +

(Ph3P)4Pd

3-Allylindoles are generatedfrom lC allyl transfer process which acconry correspondingaryl allyl ethersroand frm allyll I and propargyl carbonates.r:

.
:t

(PhsP)4Pd

-\-rn

THF

1OOO

\%{,tr* 82%

Suzukicoupling. Synthesis of biaryls by the Suzuki coupling at ambient temperaturein the presenceof the Pd catalystand TlOHl5 and using recoverableand (PqP)4Pdcatalystl6havebeenstudied.The cross-coupling of reusablepolymer-supported quite The successful.lT is arylboronicacids with poly(ethyleneglycol) iodobenzoates

3g

Tetrakis(triphenylphosphine)palladium(0)

by the use of a catalyzedreactionof bulky arylboronic acids with halopyridines is favored partners for coupling as well serve salts strong base and large cations.rs Diaryliodonium arylboronic acids.le starts from A method for the stereoselective synthesis of Cr-silylstyrenes2o g-BBN) coupling Suzuki the by followed (with hydroboration-oxidation of alkynylsilanes of the alkenylborinateswith aryl halides.

.5=

+ PhBr

d,,'",

I

Zt\ NaOH

a-"Yo'"1orn,, O \-'^t--,,/ Functionalized macrocyclic dl using polymer-bound stannarcs

Ph

(Ph3P)4Pd

On conversion of lactones to c compounds with organostannarn

SiMe3

/

870k

a basein Intramolecularcoupkngofphenolswilhhaloarenes' Using CsrCO, as for Preference couplingis quite regioselectivethe Pd-catalyzed N,N-dimethylacetamide couplingat theo-positionof thehydroxylgroup(vs.p-position)is noted.2r

(( 6r...-,SnBue

OH

A \z\

a-\ \,^..

(Ph3P)4Pd > Cs2CO3

",J I

AcNMe2 9oo

oH 4-r

.\.V l t t

l

\Z\ru'

Other reactions of organon Pd(0) is regiochemically distirrt I Insertionofcarbon dioxide into r

I

COOMe

COOMe

76'/"

.k

pfi to Geminal allylic diacetates undergo substitution.22 Access Stillecoupling. methyl of couplings 2,3-disubstituted and 2,3,5-trisubstituted furans23 by stepwise to 3-tributylstannylsulfolene of conversion the and 2,3-dibromofuran-5-carboxylate preparations are among the useful 3-arylsulfolenes (and thence to 2-ary1-1,3-butadienes)24 2-organoselenenyl-1,3-dienesare as such dienes Functionalized method. based on this -selenoalkenes -stannyl-I with haloalkenes'2s available by Pd/Cu cocatalyzedcouplingof 1

Brr-

,,-(}"ooMe

(Ph3P)4Pd

V:.,..r.snBus ;;*

t''-)--o

ZrJr)=cooMe

(prb

,-snBu3

_5

60%

8,.r3 TH;

(E:Z >95:5)

Thect Negishicoupling. as demonstrated 5-bromo-2,4-pentadienal.sB1 styrenes containing fluorine aro

moieties

synthesis of terminal alk.rncs coupling,32ethynylzinc bromi& corresponding Grignard rcagea arylation [(Ph3P)4Pd-ZnCl.]."

73lo

Tetrakis(triphenylphosphine)palladiun(0)365 11,r,'redby the useof a t .,,upling Partnersfor

On conversion of lactones to cyclic ketene acetal phosphatesand coupling of the latter compounds with organostannanes,cyclic enol ethers are obtained.26

s:\:!'neslo starts from t fr :he Suzuki couPling

* B,3snA

(/o';to*r'

(Ph3P)4Pd- LiCl

8Oo/"

Functionalized macrocyclic alkenescan be synthesizedby intramolecular Stille coupling using polymer-bound stannanes.The products are releasedduring the coupling process.2T

Ph 1t\

SiMe3 O

" ' - [ " . , , t t t ^ ,

R

O

r

(Ph3P)4Pd

a7'. 3; ('.CO3 as a basein nc.:erive. heference for

PhMelooo

MEMO,,{4'

no% 54/" R=MEM +

,U"

s :,,rcd.:l

7(aA"l-,,^r.'

R=H

(Slzearalenone

6a.,,SnBuz

Hydrostannylation of allenes catalyzed by Otherreactionsoforganostannanes. Pd(0)is regiochemicallydistinctfrom reactionspromotedby Lewis acids Ie.g.,(C6Fs)38].28 Insertion of carbon dioxide into allylstannanesgives stannyl 3-butenoates.2e COOMe

5SnBus

(Ph3P)4Pd +

u!..:rtution.22Access to s- J()uplings of methYl if,-:\ l\tannylsulfolene to n: :hc useful PreParations ox'.c'nenll-1,3-dienesare 1.n.. $ ith haloalkenes.25

3r__.,_ / \ \ VolcooMe 73'/"

Ph 60"/"

Bu3SnH THF ^

r w: Pri

Ph3B

BuaSn

+

Bu3SnH PhMe Oo

Ph

(E;Z>95:5) Negishi coupling. The coupling of organozincs with halides does not affect enal moieties as demonstrated by a facile synthesis of 2,4-alkadienals from 5-bromo-2,4-pentadienal.30By using fluorinated ethenylzinc reagents in the coupling styrenes containing fluorine atoms in the side chain are readily prepared.3l For a direct synthesis of terminal alkynes from aryl and alkenyl halides by the Pd(0)-catalyzed coupling,32ethynylzinc bromide is recommendedfor sterically demanding caseswhere the corresponding Grignard reagent is inefficient. Note that l-alkynes undergo catalytic arylation [(P\P)4Pd-ZnC12].33

t{i

1[l

36

Tetrakis(triphenylphosphine)palladium(0)

Arylcyclopropanes are obtained from coupling using cyclopropylzinc halides.3a Carbonylative coupling. Symmetrical ketones are formed on treatment of (PhrP)oPd organozinc reagentswith under CO. In the presenceof aryl iodides the reaction gives with RZnI RCOAr.35 Methacrylic acid derivatives are formed by a Pd-catalyzed reaction of allene, carbon monoxide, and nucleophiles.s6

Phl

NHBoc

V{Y=

(Ph3P)4Pd

eooue

Pht zlr'NHBoc i l : O

CO / THF

Arenes from enyl. intermolecular cyc load the products are 2.64i

that benzynes underer o-trimethylsilylphenlI

Hx---E

COOMe

60%

(Ph3P)4Pd>

P h N H 2 + c o . H

tl

ph

THF- HOAc

Cyclization.x ft is highly dependenton

N H

80"/"

.J

Carbon monoxide diverts the coupling of diaryliodonium salts and arylboronic acids to the generation of diaryl ketones.3TAdditive carbonylation leading to B-substituted butenolides38is observedwhen propargylic alcohols and diaryl chalcogenidesare subjected to the carbonylationconditions. The reductive carbonylation ofpropargyl alcohols in the presenceofthiols which results in p,y-unsaturatedthioesters3eis in contrast to the formation of 5-hydroxy-2,3-alkadienoic estersaofrom ethvnvloxiranes.

Ph-SH

(Ph3P)4Pd

\.,

n"oJ

S

\

.J A"oJ-\

PhS

T H F- T S O H

MeOOC

Y

co

MeOOC The tricarbonylchromium complexes of (o-chlorophenyl) but-3-en- | -y1 ethers undergo carbonylative cyclization stereoselectively.alHomologation of benzylic alcohols to form arylacetic acids is achievedby Pd(0)-catalyzedcarbonylation using HI and CO.a2

(Ph3P)4Pd Et3N/ MeOH

co

COOMe

MeCN - PhH R=Me

73% (>98'kde\

RearrangemenL to the bridged ring slsrr bond migration.ot Th. I

-T--q \---+Y oA3.

/,

Tetrakis(triphenylplpsphine)palladium(0) 367

rr-..nalides.3a | ,r treatment of I : "irJes the reaction r: .r a Pd-catalyzed

Arenesfromenynesanddiynes. A novel synthesis of alkynylarenes by the intermolecular cycloaddition of enynesand diynes has beendeveloped.43With enynesalone the products are 2,6-disubstitutedstyreneswhich are formed by cyclodimerization.4 Note that benzynes undergo trimerization to give triphenylenes in situ, e.g., by treatment of o-trimethylsilylphenyl triflate with CsF in the presenceof (Ph.P)oPd.as

t"-:_1

t, r Boc

(Ph3P)4Pd + cod / THF

OCt'le

1000

867"

c

Cyclization.a6 Intramolecular alkylation involving an allylic acetateas electrophile is highly dependenton the locationofa silyl substituentin the substrate.

.Y ll -..

r:
98%de)

liI}i,ii iil rll

Ii

368

Tetrakis(triphenylphosphine)palladium(0)

lNuguy^.a, K., Shimizu, I., Yamamoto, A. CL 1143 (1998). 'Honda, M., Morita, H., Nagakura, l. JOC 62,8932 (1997). II 38, 3623 (1997). lPyn., S. G., O'Meara, G., David, D. M. "Vicart, N., Gore, J., Cazes,B. 254, 11063(1998). sshi-, J.-G.,Nakamura,H., Yamamoto,Y. JOC 63,8470 (1998). 6Nuku-u.u, H., Sekido,M., Ito, M., Yamamoto,Y . JACS 120, 6833 (1998). TShi-. J.-G..Yamamoro.Y. JoC 63.3067 (1998). 8ohno, H., Ishii, K., Honda, A., Tamamura, H., Fujii, N., Takemoto, Y., Ibuka, T. JCS(Pl) 3703 ( l 998). vCacchi, S., Fabrizi,G., Pace,P. JOC 63,1001 (1998). l0Monteiro, N., Balme, G. S1,746(1998). rrcacchi, S., Fabrizi,G., Moro, L. SL74l (1998). r2Monteiro, N., Amold, A., Balme, G. Sl, 1111 (1998). r3Hayashi, M., Saigo, K. IL 38, 6241 (lgg'7). raTsukada, N., Shibuya, A., Nakamura, I., Yamamoto, Y. JACS 119,8123 (199'7). ''Anderson, J. C., Namli, H., Roberts, C. A. f 53, 15123 (1997). r6F"ng"r, I., Le Drian, C. TL3g, 4287 (1998). "Blettner, C. G., Konig, W. A., Stenzel,W., Schotten,T. SI 295 (1998). 'rzhung, H., Kwong, F. Y., Tian, Y., Chan, K. S. "/OC 63, 6886 (1998). leKang, S.-K., Lee, H.-W., Jang,S.-B., Ho, P.-S.JOC 61,4'720(1996). 20Soderquist, J. A., Leon, C. TL39,3989 (1998). ''Hennings, D. D., Iwasa,S., Rawal, V.H. JOC 62,2 (1997). "van Heerden,F. R., Huyser,J. J., Williams, D. B. G., Holzapfel,C.W. TL39,5281 (1998). "Bach, T., Krtiger, L. SL I185 (1998). 2aBew, S. P., Sweeney,J.B. SL 1273(1gg':.). 25Mu, Y., Huang, X. JCS(Pt ) 2953 (lgg'7). 26Nicolaou, K. C., Shi, G.-Q., Gunzner,J. L., Giirtner,P., Yang, Z. JACS 119,5467 (199'7). ''Nicolaou, K. C., Winssinger,N., Pastor,J., Murphy, F.ACIEE37,2534(1998). 28c"uo.gyun, V., Liu, J.-X., Yamamoto,Y. JOC 62,2963 (1997). ?eshi, M., Nicholas,K. M. JACS 119,5057 (199'1). 30vicart. N.. CasterCaillabet,D., Ramondenc,Y., Ple, G., Duhamel,L. SL 41 1 (1998). 3lNguy"n, B . V . , B u r t o n ,D . J . J O C 6 3 , 1 7 1 4( 1 9 9 8 ) . "Negishi, E., Kotora, M., Xu, C. JOC 62,8957 (1997). "Crisp, G. T., Tumer, P. D., Stephens,K. A. JOMC 570,219 (1998). '"de Lang, R.-J.,Brandsma,L. SC 28,225 (1998). "Jackson, R. F. W., Turner, D., Block, M. H.JCS(PI) 865 (1997). tucrigg, R., Monteith, M., Sridharan,V., Terrier, C. 754, 3885 (199s). ''Kang, S . - K . ,L i m , K . - H . , H o , P . - S . ,Y o o n , S . - K . ,S o n ,H . - J .S C 2 8 , l 4 8 l ( 1 9 9 8 ) . ttogu*u, A., Kuniyasu,H., Sonoda,N., Hirao, T. JOC 62,8361 (1997). 3exiao, W.-J., Alper, H. JOC 62,3422 (lggi). a0Piotti, M. E., Alper, H. JOC 62,8484 (199'7). otc.ourr", B., Xu, L.-H., Bemardinelli,G., Kiindig, E. P. SL 658 (1998). otl-in, Y.-S., Yamamoto,A. BCSJ 71,723 (1998). 43c"uo.gyun, V., Takeda,A., Yamamoto, Y. JACS 119, I l3l3 (1997); Gevorgyan,V., Quan, L' G., Yamamoto. Y. JOC 63. 1244 (199$. *Gevorgyan, V., Tando, K., Uchiyama, N., Yamamoto, Y. JOC 63,7022 (1998). 45Pena, D., Escudero,S., Perez,D., Guitian, E., Castedo,L. ACIEE 37,2659 (1998). a6Thorimbert, S., Malacria, M. TL 39, 9659 ( 1998). aTwhite, J. D., Kim, N.-S., Hill, D. E., Thomas,J. A. S 619 (1998).

Tetrakis(triphenylphmphir Sonogashira coupling. substituent (i.e., enol and yno alkenyl iodides.r Alkynylsih alkenyl and aryl triflates.:

Ro--

+

RO----

+

'-\

l-

\\

co{

lDussault, D. G..S1 P.H.,Sloss, 2Nirhih*u,Y., Ikegashira. K..Vr

Tetrakis(triphenylphcphb Hydr ocarbonylation ol t l-alkynes under CO in thc generationof the regioisonu reactionon 5-hydroxy-I -pen

?*lll + F

Diboration of allcncs. reactionof al Pt(0)-catalyzed

(Prf

.,-cooEt o. ,8-t o

(Pr{ OMe

o. B-

o

Tetrakis(triphenylphosphine)platinum(0)

369

iodide' 18' 349-350 Tetrakis(triphenytphosphine)palladium(0)-copper(I) Stereodefined enynes including those bearing an alkoxy sonogashiracoupling. on coupling with substituent (i.e., enol and ynol ethers) are readily preparedfrom alkynes the coupling with in alkenyl iodides.r Alkynylsilanes can be used instead of l-alkynes alkenyl and aryl triflates.2 l*,' : )

I h u k a ,T . J C S ( P 1 )3 7 0 3

RO---

*

- Cul (Ph3P)aPd

'-\coH,

D

l: : .997)

-CaHg

i-PrNH2 - Cul (Ph3P)4Pd

l---:r

RO---:

RO:-\\

\\ coa/

*O-:-\

i-PrNH2

coa/

lDussault, D. J' SL 1387(1998)' P. H., Sloss,D. G.,Symonsbergen' 2Nirhihu.u,Y., Ikegashira, K., Mori, A'' Hiyama,T' CL 1233(199'7)'

t I I

(1998), I .'r -re.5281

(1997). ( . I 19.5,167 _ f.f"# (93 : 7)

r-

r : i \ o r g y a n r V . , Q u a n ,L . G . ,

:, :: 1998). ? t^<e( 1998).

90'/.

(Ph3P)4Pt

OMe

-fo. l B -fd

-

.oJl bf

ioot'

the

2 '#

+!\

370

Tetrapropylammoniumperruthenate,TPAP

'Ogur"u, A., Kawakami, J., Mihara, M., Ikeda, T., Sonoda, N., Hirao, T. JACS llg,12380 (Igg:). "Ogawa, A., Kawabe,J., Kawakami, J., Mihara, M., Hirao, T., Sonoda,N. OM 17,31l t (1998). 'Ishiyama, T., Kitano, T., Miyaura, N. fZ 39, 2357 (Iggg).

N,N,N',N'-Tetramethylguanidine.17, 332 As base. Nitroaldolcondensationr and conjugateadditionof dialkyl phosphitesto o,,B-unsaturated carbonylcompounds2 arereadily catalyzedbytetramethylguanidine at 0o. rSimoni, D., Invidiata,F. P.,Manfredini, S.,Ferroni,R., Lampronti, L, Roberti,M., Pollini,G.P. TL 38,2749(199'1). 2Simoni, D.,Invidiata, F. P.,Manfredini, M., Lampronti, I., Rondanin, R.,Roberti, M., pollini,G. p. It 3 9 , 7 6 r 5( 1 9 9 8 ) .

2,2,6,6-T etramethyl-4-methoxy-1-oxopiperidinium

chloride. a-Oxygenationofketones. Piperidinoxylation of ketones is observed with the reagent I (prepared from TEMPO and chlorine gas) in MeCN at room temperatureJFor ketones containing an active methylene group thecr-oxyfunctionalized derivatives undergo elimination to afford c-diketones on heatine with TsOH in MeCN.2

,/u

ketones.2 A modified perruthenate and trimeill

rYates, M. H. ZI 3E,281I , 2Tokrnugu, Y., Ihara,M.. F 3Hinren, B., Ley,S. V. .lC

Thallium(Il!

acetatcr a-Ketols.t The re the products with aqueo

rLee, J. C.,Park,C.,Chor.

Thallium(Ill)

acetatH 2-Alkyl-S-aryloxu condensationof alkyl cy

J. C.,Hong,T. i.L 3t.

*N=o

V-;

"a'* (1)

Oxidations. This N-oxide) has been used the presence of AgOA
z\....\rA" I

.I /\48 , 3

a\

.\

A....("A"

--i-H o A.l^,lD

r,-^,, N a o H^ a) #T^"

-i-':

125o )

(

)

(

H

(-'("' ttteOV

Decarboryl of Bu.P(catalltic r process.

Tributylphosphine 387

'Bubnou,Y. N., Klimkina,E. V., Ignatenko, A. V., Gridnev,L D. ZL 38, 4631(199'l).

ilc. hr the [3+2]cycloaddition rg,:nds has been extendedto r -rcloaddition enables the

Triarylcarbenium hexachloroantimonates. A study of the Mukaiyama aldol reaction using 7-arylAldol reactions.t hexachloroantimonates1 as catalyst shows 1,2;5,6-dibenzocycloheptadien-7-ylium stereochemicaldependenceon the nature of the silyl enol ethers and the counterlons.

..: l.

.f)ll \,/\'('9

tmine. Iu,':,,alkanesrby this reagent iit. rre not affected. Selective I ..r'frrtrat€containing also a | .-nrc'mbered)undergo ring or ',r.krI derivatives).2

Ar

sbct;

(1)

rChen, C.-T.,Chao,S.-T.,Yen,K.-C. 5L924(1998).

Triazidochlorosilane. Tetrazoles.t Primary amides are converted to 5-substituted tetrazoles on reaction with triazidochlorosilanein refluxing MeCN (8 examples,76-94Vo).

,,COOME

'El-Ahl,A.-A. S.,Elmorsy,S. S.,Elbeheery, (1991). A. H., Amer,F. A. rL 38, 125'7 rBr.rrcdfrom l-alkynes by the ri:it' u ith CuI, KI in DMF at . r:rir.rguchi,M., Sakai, H.,

I l < . q r1 9 9 8 ) .

Tributylphosphine. Isocyanates.t The Mitsunobucomplex from BqP and diisopropylazodicarboxylate is useful for condensingaminesand carbondioxide. 2-Arylidenesuccinicesters.2 A convenient preparation of these esters from aromaticaldehydesand fumaric estersinvolvestreatmentwith BqP and then hydrogen peroxide.

(Y"'o .

's-n.trtuted

2-allyl-t,2,3,6in; rt 160-200' (neat) and a::,,htained.

v"oV

rr"oot'

Erooc,'

Bu3P/ THF ;

..il-=YcooEr

\"oo=,

tl"oV 82"/o

l'

""or,.,-(-)* I H

Decarboxylation.3 cr-Imino acids undergo catalytic decarboxylation in the presence (catalytic quantities)at room temperature.Acetic acid or pyridine can acceleratethe ofBu,P process.

388

Tributyltinchloride

Cyclopentenesand 2,5-dihydropyftoles.a 2-Alkynoic esters react with o,Bunsaturated esters and N-tosylaldimines to give cyclopentenecarboxylic esters and N-tosyl-2,5-dihydropyrrole-3-carboxylic esters, respectively. The processes probably involve C-C bond formation which is initiated by the conjugate addition of Bu3P to the allenic esters (derived from the alkynoates) to generate ester enolates to act as Michael donors, and a subsequent cyclization furnishes phosphonium ylides. An elimination

accomplishedby trih BurSnCl and Et.SiH alkenylstannanes( E e

reaction via prototropic shift regeneratesthe catalyst.

\

cooEt I

tll

+

Ar / N

I

J

/-\

R,,,,\N/,,,Ar

.:I S

R)

Alkylphosphotu chain lengthscan b< propyl)and l-alkerr NaBH.,an Bu.,SnCl,

cooEt BusP/ PhH

Ts

to'N"ill,I. A.,Souttr 2c"uorgyun, V.,Liu.J -

rHorvath, M. J., Saylik, D., Elmes,P. S., Jackson,W. R., Lovel, C. G., Moody, K. TL40,363 (1999). 'McCombie. S. W., Luchaco,C. A. ff 38, 5'175(199'7). 3Bu.ton, D. H. R., Taran,F. T 54,4777 (lgg}). 'Xu, 2., Lu, X. TL 40,549 (1999).

3-Tributylstannyl-2-(trimethylsilyl)methylpropene. radicalallylationras well as thosevia 24Trimethylsilyt)altylatian. Photoinduced areusefulsynthetically. ionic pathways(e.g.,reactionwith acidchlorides2) of aldehydes andimineswith reagentI in 4-Methylenepiperi.dines.rCondensation 4-methylenepiperidines. thepresence of Me.SiClresultsin 2,6-disubstituted

38alczewski,

P., Pietnl

Tributyltin diisopro Michael reactb enolateswith enon enolizationagentthc

Ph. ., .

P

Y O M e + Ph ,u-SiMe3 -

t

+

LSnBu3 (1)

("n \pn

* oHq Pr

Me3sicl MecN

-f{rrn Y

Pr

697o

'Clive, D. L. J., Paul,C. C., Wang, Z. JOC A,'7028 (199'1). 2Kang, K.-T., Sung,T. M., Kim, J. K., Kwon, Y.M. SC 27,11'73(199'7). 'Kang, K.-T., Kim, E. H., Kim, W. J., Song,N. S., Shin, J. K., Cho, B. Y. SL 921 (1998).

Tributyltin chloride.13,315;18,368 Alkenylstannanes. Aryl ethyl sulfoxidesareconvertedto (1-arylthiovinyl)tributylstannanesron treatmentwith LDA and Bu.SnCl. Hydrostannylationof alkynes is

lshibutu, L, YasudaK

Tributyltin hydrkl 351-361;lE, 368-3 Alkenylsnnut (dba)rPd, and Ph.I couplingimmediatc l-bromoalkenestlte reagent.

Tributyltinhydride

:L'rcr with c[,Brtr,'.rlic esters and Fr,\.csses probably il::',n of Bu,P to the

389

accomplishedbytributyltinhydridegeneratedinsitu.Thus,amixtureofthealkyneswith into the a Lewis acid (e'g" Ph'B) is transformed BurSnCl and Et,SiH in the presenceof alkenvlstannanes(8 examples,7O-90Vo)'

l. i,, tct as Michael dc- .\n elimination

oI s+

LpA/ rHF:

1->

,zsysnaus

Bu35nCl

esters with P-alkyl groups of different Alkylphosphonate esters'3 Phosphonate

aaatrt

chainlengthscanbepreparedfromiodoalkylphosphonates(alkylbeingmethyl,ethyl' process' using an initiating system comprising propyl) and l-alkenes by a radical addition BurSnCl, NaBH4' and EtrB (O2)'

r r

/L 40,363(1999)'

ro'N"ill, I. A., Southem' J. M. sL 1165(1997)' 2ceuo.gyun,V', Liu, J.-X'' Yamamoto'Y ' CC 3'7(199'l)' 3Balczivski,P.' Pietrzykowski, w' M' r53' 7291(1997)'

Tributyttin "'";rr;;;;;;;;;;.'diisoProPYlamide' ,,?rlselectivity

is observed in the reaction of tributvltin

enolateswithenones'Ontheotherhand,usingbutyldichlorotindiisopropylamideas the syn-isomers' enolization agent the major products are : .1-rrell as thosevia t:.-1.1\.

u.i. \\ith reagentL in an.l l llcs.

ph.A "'Y'o""

o

J

Ph

Pr

I -..:. ithiovinYl)tributYlnr..::r()nof alkYnesis

Io

-

Y f Y o P h o

OMe Ph I ,^. .Ph + \1 Y f ll

o

66%

(22 : 78\

i-Pr2NSn(Bu)Cl299'/"

(82 : 18)

:

ll

P h o

'Shibutu,I., Yasuda'K', Tanaka,Y', Uasuda'M'' Baba' A' JOC 63' 1334(1998)'

-3 325 -333 : 16' 343-3 50; 17' hydride. 13, 3 16-3 19; 14, 3 12 l8'' 15' 351-361; 18, 368-371; 19, 352-353 by employing ButSnH' Hydrostannylation of l-bromoalkynes Alkenylstannanes. It is convenient to effect a Stille (dba),Pd, and PhrP provides (E)-alkenylstannanes'r -alkynes and Pd catalystis already present'From I coupling immediately becausethe proper tin requires only catalytic amounts of the l_bromoalkenes the synthesis of l,3-dienes2

Tributyltin I 998).

*

i-Pr2NSnBu3

NPh

65"/.

o

PhV.\/Ph

OMe tn]r.,Ph

reagent.

390

Tributyltinhydride

Dehalagenation, The stereochemical results in the debromination of l-bromol-alkenylboranes3 according to the bulkiness of substituents on the boron arom are interesting. Stereoselective removal of the (E)-configured bromine atom of 1,1-dibromoalkenesawith the BurSnH-(pqp)4pd combination is synthetically valuable. Acid chlorides are rapidly converted to aldehydessat room temperature on exposure ro BurSnH-(dppe)Nicl' although sometimes decarbonylation occurs as side reaction. This

Deoxygenative irradiation (350 nr cycloalkoxy radica and the carbon rad cyclization process

method is applicable to the synthesisof aldehydescontaining nitro groups.

n.B\

''-k

R2B

/< R = dicyclohexyl R = cycloherylthexyl

,n

",fk

Bu3SnH

(99 : 1) (1 : 99)

Reductive detr hexacarbonyldicob possibleto conven

Bu35nH

rr' Br

+

(Ph3P)4Pd PhH

(

the decomplexatiot 82k

A method for the conversion of iodides to alcohols via free radical intermediatesconsrsts of trapping by 2,2,6,6-tetramethylpiperidin-I -oxyl and subsequentreduction.6

(ocbc

(oc)3c Bu3SnH TEMPO PhH ^

50v. Deoxygenation. The centrally located functionality of 2,3-dihydroxycarbonyl compoundsis selectively destroyedvia their cyclic thionocarbonates,by meansof Bu.SnH.7 Ring expansion of certain fused cyclopropylmethyl xanthatesoccurs,8the extent of which has some dependenceon the concentrationof Bu.SnH.

rBoden, C. D. J.. Pr 2Maleczka, R. E.. Tc lHoshi, M., Takahar aUenishi, J., Kawalu sMul-gu, C., Mann 6s"hultr, A. G.. Dar. 7Rho, H.-s. sc 27. l 8Kantorowski, E. J..

eKi., s.,oh,D. H..

loHosokawa,

b"j.""

S.. Isoh

Bu3SnH(>0.8M)

.......'...,...............* PhH 1350

+

Tributyltin hydri Cyclizttions. bis(phenylthio;ac

391 Tributyltinhyrlride-2,2'-azobis(isobutyronitrile)

n,:.1nationof l-bromot'r. :he boron atom are ni rromine atom of i. .r ntheticallyvaluable. tO ll\-:.1iure On exPOSUre This u1. ." :ide reaction.

crr-haloaldehydesby Deoxygenative cyclization to form 5- and 6-memberedrings from method'e The a useful is Ph3P and BurSnH with mixture irradiation (350 nm) and its Ph,P=O eliminate which triphenylphosphine by in situ cycloalkoxy radicals are captured radical Tandem hydride. tin the from hydrogen with and the carbon radicals are supplied cyclization processesare possible'

oEt

f- jrrJUPS.

o{

Bu3snH

",8/:X

hv

Ph3P

)-A t t \,,'t-J

)

H 78%

''^ Br

for removal of the Reductive decomplexation.to Although the common practice oxidants, it is also mild involves complexes hexacarbonyldicobalt residue from alkyne is used If triethylsilane Bu.rSnH' with (Z)-alkenes possible to convert the complexesto free the decomplexation is followed by in situ hydrosilylation'

:2 consists r! J. ::ltermediates n: :r.luction.o

-l "--z__

t: ): : i-dihydroxycarbonYl r!.. r\ meansofBu.SnH.7 c..-:-.' the extentof which

(OC)sCo

Bu3SnH

(OC)sCo

PhH A

\\ Ph

6170

rBoden, D. J., Pattenden,G. JCS(P1)2411 (1996)' C. 2Maleczka, R. E., Terstiege, I- JOC 63,9622 (1998)' 3Hoshi,M., Takahata,K., Arase,A. TL38,453 (1997)' aUenishi. Kawahama,R., Yonemitsu,O., Tsuji, J' JOC 63,8965 (1998)' J., 5Mul^anga, C., Mannucci,S., Lardicci, L. TL38' 8093 (1997)' us.hulti, A. G., Dai, M., Tham, F. S.' Zhang,x. TL39' 6663 (1998)' 7Rho, H.-s. sc 27,388'7(199'7). sKantorowski,E. J., Borhan,B.' Nazarian,S', Kurth, M' J TL39' 2483 (1998)' eKi'n, s., oh, D. H. sL 525 (1998). r0Hosokawa,S,, Isobe,M. TL39,2609 (1998).

19, 353-35'l Tributyltin hydride-2,2'-azobis(isobutyronitrile)' example'the Cyclizations. Formationof five-memberedrings is favored' For of 5-hexenalgives 2-methylcyclopentylphenyl sulfide'r r-Butyl bis(phenylthio)acetal

3g2

Tributyltinhydride'2,2'-azobis(isobutyronitrile)

3-bromopropylsulfideandN-(3.bromopropyl)iminesundergocarbonylativecyclizationto under co. Several macrocycles afford the y-thiolactone2and pynolidinones,3 respectively, and a transannularcyclization to have been prepared4on the basis of radical cyclization, form a propellane is the basis of a route to modhephene'5

Br CO - Bu3SnH

O-\j

^*";il

(>1 ,P \-J N< \2

81"/o

t_._Z\

=(a\

Bu35nH

o .'j=/

AIBN / PhH

\-,=,\,.,J

"+il)-:* H,

RearrangemcnE opening which is foll 2-allyloxy enonesfct from 3-arenesulfonll BurSnH-AIBN.

modhephene

Formationofcls3-alky1-2-hydroxymethyl-4-trimethylsilylmethylene-cyclopentanol group attachedto can be initiated by the free radical generatedfrom a bromomethylsiloxy of to-formyl oxime ethersT c-3 of a 1,5-enyne.6The diastereoselectivereductive cyclization is also a useful Process.

o.

o=1r--trotvte

HO Bu3SnH

N.

$HOMe

\-it

AIBN / PhH A

\,./ 79"/o (trcns: ctb 18 : 1)

Me3Si

OBn Bu3SnH

Ring-opening d aldehydes in the presr bearing an a-ethyl g

methylenecycloprope

A I B N/ P h H A

o il

Thetandemcyclizationinitiatedbydeselenylation,C.radicaladditiontoan to generatea new radical at N-aziridinylimine molety which is followed by decomposition theacceptorsiteandadditiontoasidechainvinylgroup,isthebasisofskeletalconstruction toward a synthesisof pentalenene'8

^,/Yv \ 867"

,r It!

til

Ir j

I

i i I

Tributyltinhydride-2p'-g765;.1;sobutyronihile) 393

Lr.rtr r e cyclization to Sc\ !'ral macrocycles nnuiar cyclization to ( 1 : 6 ) 84"/"

N-4

:H,

Rearrangements, Cyclopropylalkenoyl selenidesundergo deselenylation and ring opening which is followed by reclosure to the cyclohexenones.eBoth cyclic and acyclic 2-allyloxy enonesform ketyls which are prone to capture the allyl group.roAryl migration from 3-arenesulfonyloxyalkyl iodides to give 3-arylpropanolsrr occurs on reaction with BurSnH-AIBN.

tl

BuasnH

modhephene

t t \.,'\

A I B N/ P h H A

n.:nc'- cyclopentanol o\\ rroup attachedto >i,'nnr I oxime ethersT

l

607o

^:r'tlJ

Bu3SnH

+

A I B N/ P h H

50 - 76v" - - s 1 8: 1 )

\--oBn ,{

Cyclopropyl ketones react with alkyl iodides and Ring-opening alkylation. aldehydesin the presenceof Bu.SnH-AIBN by a ring-opening pathway, leading to ketones bearing an a-ethyl group.12A related bicyclizationr3 is via intramolecular addition to the methylenecyclopropaneunit following by ring opening and another addition.

,/\/ ' h.r. addition to an rl-l::lnerer reaction t: .reid thiol esters

l

tEl Kuiln,L., Pinot-Perigod,E. T 54,3799(1998). 2Ku*ur".M., Teshima, M., Saito,S.,Tani,S. A 48,2103(1998)' 3l*ur^a,T., Kataoka,T., Muraoka,O., Tanabe,G. JOC 63,8355(1998). oKitu,Y., Iio, K., okajima,A., Takeda, K., Whelan,B. A., Akai,S. SL 292(1998)' Y., Kawaguchi, 5Kudrin,Z.H.,Lyzwa,P.,Luczak,J.,Andrijewski, G. S 44 (1997).

G)'

+

R-NH)-

R-NHCOCF3

+ THF

\ cocF3

85 - '100%

rKatritzky,A. R., Yang,B., Semenzin, D. JOC 62,726(199'l).

2.2.2-Trifl uorodiazoethane. Trifluoroethyl sulfates.t The conversion of ROSO3H to ROSOTCHTCF, by CF.CHN, servesto protect the sugarsulfates.Such estersare stableto many conditions used in carbohydrate manipulations such as deacetylation. Deprotection is accomplished by heating with t-BuOK in r-BuOH. rProud,A. D., Prodger,J. C., Flitsch,S. L. ZL 38, 7243(1997).

39E

Trifluoromethanesulfonicacid(triflicacid)

Trifluoromethanesulfonicacid (triflic acid). 14, 323-324;15,339;18,377;19, 362-363 Friedel-Craftsreactians. The reaction of osmium-complexedanisoles with electrophilessuchas enonesis catalyzed by TfOH.t Benzylationof arenesby a reductive alkytation2with arenecarbaldehyde acetalsinvolves an intramolecularredox process (hydrideshift) afterprotonationof thebenzylicetherintermediates.

tKolis, p., s. Kopact "Fukuzawa, S.-1..Tsu 3shah, pike, A., v. \r au"hiro, H., Waki;-an -Schildknegt, K.. Agn oAggarwal, V. K.. Va 'Marson, C. M.. Faild 8labrouillere, M.. [.c

(1ee9).

gMiyatake, K., Yarna

Diaryliodonium triflates are preparedfrom ArI(OAc), and arenesin triflic acid.l Hydrolysisof thioglycosides. Aqueous TfOH and Bu"NIOo effect hydrolysis of thioglycosides,aprobably by way of Pummerer reaction. Mannich reactions.s In situ generationof [PhNH=CH]OTf from benzyl azide in the presenceof ketones is followed by the condensationto give a-anilinomethyl ketones. The reaction pathway differs from that (amideAactamformation) promoted by TiClo.

tl

a^) \-,

TfoH> N3

Ph

tl 1^]^r.rHen

fdfluel6nsrh-na! 15,339-340;16,3l Oxidotions. EtrN.rApparentll'd Transformatb (dimethyl)iminiumr hydrolysis.Amidin bridged orthoesre monohydricalcoho

H-7uO Tt2O | NMe2

\-, 63"/"

5,6-Dihydropyrans. Either by cycloaddition6 of dienes with aldehydes (electron-richaldehydesnot suitable)or by sequentialoxo-enereaction.i the synthesisis catalvzed bv TfOH.

/-coNH2

o^o (o)

TfOH

cH2ct2

I

a-) \^.1

Ph-

rNenajdenko, V. G.. \i (1997). ^2483 'Sforza, S., Dossena-A 3ch*"tt., A. B., Chue. 4charette, A. 8., Chue" 5Charette, A. B., Chur

58v" Other preparations.

Bismuth(Ill) triflate is conveniently obtained by dissolving Ph.Bi in TfOfVCH2Cl2.8 Treatment of sulfides and alkyl esters with TfOH leads to sulfonium triflates.eThe alkyl group of the ester is transferred.

N-Trifluoromerhrq N,N'-Diprotech amineat room tempc

rFei"htinger, K., Singr

lV-Trifluoromethanesulfonylgunidines,lf,M-diprotected 399 -.19.

Lr:.()les with b,r .r reductive reJ,,r process

'Kolis, S.P.,Kopach,M. E.,Liu, R.,Harman, W.D. JOC 62,130(1997). 'Fukuzawa, S.-I.,Tsuchimoto, T., Hiyama,T.JOC 62,151(1997). 'shah,A., Pike,v. w., widdowson,D. A. JCS(?|)' u63(tgg7). -Uchiro, H., Wakiyama,Y., Mukaiyama,T. CL 567(1998). -Schildknegt, K., Agrios,K. A., Aube,J. TL39,7687(1998). oAggarwal,V. K., Vennall,G. P., Davey,P. N., Newman,C. TL 38, 2569(lggi). 'Marson, C. M., Fallah,A.TL38,9057(lggil. 8labrouillere, M., Le Roux,C.. Gaspard.H., Laporterie.A., Dubac,J., Desmurs,J. R. TL 40,285 fi999\. eMiyatake, K., Yamamoto,K., Endo,K., Tsuchida,E. JOC 63,7522(1gg8).

rr . .rzidein the ' : \ i t ( ) n e sT. h e

Trifluoromethanesulfonic anhydride (triflic anhydride). 13, 324-325;14,324-326; 15,339-340; 16,351 -358; 18, 377-378; 19, 363-365 Oxidatians. Alcohols are oxidized (RCIOH -r RCHO) by using MerS-TfrO and EtrN.l Apparently the system is a variant of the Swern oxidation. Transformations of amdes. N,N-Dimethylformamide forms triflyloxymethylene (dimethyl)iminium triflate which reactsreadily with alcohols. Formic estersare obtained on hydrolysis. Amidines are available similarly.2 Other amides can be converted to estersl bridged orthoesters,aand thiazoliness by quenching the analogous iminium salts with

i(

monohydricalcohols,alkane-1,1,1-trismethanols, and 2-mercaptoethylamine, respectively.

r .r,id.r :.,.Jrolysis of

H:7zO |

NMe2

Tl2o +

H

+ 'Yoso2cFs NMe2 Tfo

T=t,

pnAo

.rldehydes hr .r nthesisis ti

NaOH

RoH HyoR

*ilu", Tfo

tYo* o

TtzO-py/CHzClz,, Mec(cH2oH)3

?X ,nk?) 69%

'Nenajdenko, V. G., Vertelezku, P. V , Koldobskij, A. B., Alabugin,I. V., Balenkova,E. S. JOC62, 2483(1997). 2sforza, Dossena, S., A., Corradini, R.,Virgili,E., Marchelli,R. ZL 39,711(1998). 3ch*"tt", A. B., Chua,P. SI 163(1998). 'Charette, A. B., Chua,P. ZL 38, 8499(199'1). tch."tt", A. B., Chua,p. JOC 63,908(1998).

xr tlissolving [:( )H leads to

N-Trifl uoromethanesulfonylguanidines, N,M-diprotected. N,N'-Diprotectedguanidines.r The N-triflylamino group can be replaced by an amine at room temperature(5 examples, 85-1007o). tF"i"hting".,

K., Sings,H. L., Baker,T. J., Matthews,K., Goodman,M. JOC 63,8432(1gg8).

400

(Trifluoromethyl)trimethylsilane

o- Trifl uoromethylbenzyl bromide. Ethers. These ethers are formed by a conventional procedure (ROH, NaH, ArCHrBr in DMF) and they show stability toward free radicals such as NBS bromination conditions.

Trifluorometh;-|ri

Glycosyltlaoa fluorides is accom react when TiF. ir I

'Miethchen, R, H"sc

,9 o^4

Dh---\-n--1 h+v

Ph"\01 o--\vY

un--J4**\

/\ H

NaH / DMF un/ OMe

\\ /r\

(

Rr

vr3

'|\'/

(.Bt

X's\-O

:o-\-\i h I -* 'u,s1\;or-1* \{ ("ou" (- or,r. Ftc-',/-n

br. F.cr.,{ t t l

br.

t t l \.,,

\.,2

Triisopropylsil.r-l r Protection of I 2,5-bis(triisoproplI

substituted succim

desilylation with di

'Martin,S. F.,Limbo

s4%

lLiotta,

L. J., Dombi, K. L., Kelley, S. A., Targontsidis,S., Morin, A. M. fL 38, 7833 (1997).

L5, 34 I ; 18' 37 8-37 9; 19, 366-367 and u,s-difluoroketones. Trifluoromethyl ketones A direct approach to trifluoromethyl ketones is by reaction of estersr (also with Me,SicF. activaredby TBAF (7 examples,68-95Vo).A similar oxazolidin-5-ones2; which may be usedas Michael reactionof acylsilanesleadsto I ,I -difluoro-2-siloxyalkenes

Trimethylaluminr Opening of ox compounds such as

(Trifluoromethyl)trimethylsilane.

donorsfor the synthesisof 2,2-difluoro-1,4-diketones.l

Bu35nr ro-

H1.

Polyoxygenatcd

o ,n^r,"",

; Me3SiCF3, (BuaN)(Ph35nF2) MVK / Yb(OTO3 2Oo

,,4a/\ F

F

677o

N-(qa-Disubstituted-B,B,fttrifluoro)ethylami.des.aAddition of a [CFrl unit to ketones followed by a Ritter reaction leads to the fluorinated amides. Aromatic trifluoromethylation.s Activated nitro and cyano groups on an afomatic nucleus are subjectto nucleophilic substitution by CF, generatedin situ from Me1SiCF, and

ring-openingalkll: regioselectively(at Alkylation da

advantageofthe F-

*AX,

KF in dimethylacetamide. 'Wiedemann, G. K. S.,Olah,C. A. ACIEE3T'820(1998). J.,Heiner,T., Mloston,G.,Prakash, 2wulte.,M. w., Adlington, c. J. JoC 63,5179(1998). R. M., Baldwin,J. 8., Schofield, 3l"f"bu.e,O.,Brigaud,T., Portella, C. T 54,5939(1998). *Tongco,E. C.,Prakashi, G. K. S.,Olah,G. A. SI 1193(1998). sAdurnr, 3081(1998). V. C.,Tavener, S.J. '/CS(P1.) L. B., Sanders, D. J.,Clark,J. H., Hansen,

Ketones. Es The presence of ch A Lewisacidis em

401

TrimethYlaluminum

e ROH, NaH' ..r.h as NBS

uoromethYlzincbromide' Trifl ^ ' ^;;;;;;; A facileconversionof glycosylbromidesro the corresponding fr"-oirr., fluoridesisaccomplishedbyreactionwithCF,ZnBrinMeCN.Protectedpyranosesalso reactwhenTiFois Present. rMiethchen,R., Hager' C., Hein, M' S 159 (1997)'

: ^

-Br \

ryv\

n

-^-r---\-i

( -_

-rZ\

z w l

i \,,'

oMe

l

trifl ate. TriisoproPYlsilYl -^*;;;;;:;" N-substituted Primary aminesare protectedin the form of o,.n,nr'' the Thesecompounds*" f"T:9 by enolsitylationof 2,5-bis(triisopropylsiloxy)pyrroles' involves and Et,N. Deprotection substitutedsuccinimidesLy ,."urrn"n, with rIPS-cl hydrate' hydrazine with desilylationwith diluteHCI andtreatment tMurtin,S.F.,Limberakis, C. IL 38,2617(199'7)' -315" 18' 365-367; 19' 369-37 0 Trimethylaluminum. 15,34 | -3 42;17,312 openingofoxacycles.Theopeningofcyclicacetalsenablesaccesstointeresting compoundssuchaschiralG-alkoxyalkylstannanes''

: ..tersr (also i 'i . t. A similar i