Volume 15, Fiesers' Reagents for Organic Synthesis

I n(m, :!'f I

Fieserand Fieser's

Reagentsfor OrganicSynthesis VOLUME FIFTEEN

Mary Fieser HarvardUniversity

@

\ TT'ILE Y.INTERSCIENCE PUBLICATION

t,rhnWiley 8r Sons,Inc. \f II'YORI(/ CHICHESTER / BRISBANE / TONONTO/",]NG,'?OII

n t r( n

AJ

.4 ' J 0i ' /\ \ tl

l99: l). These enol silyl ethersare usefulprecursorsto (Z)-lithium enolates.

?

cH3cN z-c'H"-oSiCH3(qH5)' n- crH,rcHlh ) tP. I H' cH3si(c6H5)' (2, > 99:1)

JliSil#",, n -CrH,r.

/,OSi(CH3)3

sAn G. L. Larson, R. Berrios, andJ.A. Prieto,Tetrahedron (19g9). Letters,30,2g3 CH, 2-(Acetoxymethyt)-3-rrimerhytsilytpropene, (CH,),SiCHrla"rOO. (Ll,lt, Improvedpreparation:r

z5g.

Alkylaluminum halides

(

-Cl

cl.siH.cucl. N(qH.\ - -erls

-.SiCl3 [

60%

l) cH'MsBt(81%) z) ronc' Pur (gora)' t

ncz'-,zcl

H.c/-,..c\

clt

r B M. Trost, M. Buch, and M' L' Miller, .I. Org', 53,4887(1988)'

boranewith Acyloxyboranes.Yamamotoet al.t haveusedthe known reactivityof addition Thus carboxyticacidsto activateacrylicacidsfor Diels-Alder reactions. as formulated 1, which of BHT.THFto acrylicacidsat 0'furnishesan acyloxyborane proceedssatisfactorily undergoescycloaddition(equationsI and II). The reaction BLI' "u"n *h"n borane is used in catalytic amounts.A chiral acyloxyborane' asymmetric an preparedfrom a tartaric acid derivative,can serveas a catalystfor Diels-Alder reaction(equationIII).

I l-th

rrb

q'O'too" (D c'z:cHCoo"BH:'rHF,)ro!.":.", I

,lCHt

0I) CHr:C.

'cooH

cH,cHr o . l t l l cH2=c-c=cH2 BH3.rHF\"odC:Crr, ) )_--z 4e% /""""1 CH, CH,

COOH CH,

CHt

".Og-fiT"cooH (ur)CH,:sg6oo el* \,/

\r/

(78Voee'1 Am' Soc' 110'6254(1988)' I K. Furuta,Y. Miwa,K. Iwanaga, andH' Yamamoto,

lry

halides. Alkylaluminum -I4+2|CycloadditionofN.benzytiminesandadiene.Diethylaluminumchlo-

d(l trl .l

(2) with ride is the bestLewis acid for promotingadditionof N-substitutedimines (9,302-303).1 the activateddiene 1

r! E T

Alkylaluminum halides

?'",

4ost(c"")" t cHroA611,

(cH3)3sio\ /ocH3 n'-N\

NR'

il

R,VoCH3

,

I

R = CoHs, R'= Bd

o

h n h

tl

ntva l r l

)

R,,,,.yOCH.

t\

The reactionof the cyclohexylidene ketal 3 of a chiral imine, preparedfrom l-threonine, givesa singleadduct(4), which is convertedby known reactionsinto (5). xylo-daunosamine

, ?H

HNBzI oCH,

cH ,+1 # *cH ,|A| oH

ioocH,

4 (tnEo)

J

,"u"..lrt.p,

5

tr-

rh

H.o*

l l l - - - - -

AsymmetricDiels-Alder reaction.2 The chiral menthyl (S)-3-(2-pyridylsulfinyl)acrylate(1) undergoes[4+2]cycloadditionwith the furan 2 in the presence of (CrHr)rAlClat -20' to give the endo-and ero-adducts3 in the ratio -2: 1, both in about 93Vode. The endo-adduct(3) was convertedby known reactionsto 4, which is openedby lithium hexamethyldisilazide (L2,257)ro the unsaturatedacid tn 56Voyield. Remainingstepsto methyl (-)-triacetoxyshikimate(5) includedebenzylationand acetylation.A similar sequencewith exo-2should provide (+)shikimicacid.

Alkylaluminum halides

COOMen

H-*

ll

COOMen+ exo-2(29Vo)

"?i--*

SOPY (50Vo) endo-3

I

r!J :n!

I

l) PBrs(84%)

I zyuu.1ls*) Ni(45%) 3)RmeY J

es I I I

I ' t

coocH3 Bdo 4

I

l) LiNCNS)2(56%) 2) TMSCI-NaI; AqO-PY (53%)

AO=A/COOCH3

t

t

AcO'\a

)

l

I

OAc 5, o,o-168" alkene 1 with Ari(20)-steroid enereaction'3 The reaction of the Stereoselective diastereoselechigh with (CH)'AlCl proceeds acetylenicaldehydes"u,Jf'"J by centers' chiral tivity (about 95:5) at both OH

I

-2 (>95:#0"

It

BFo'SrR.

+ (R)-2

BocH3t*|-(Prol.u", si(cHJ3 /f\

si(cH3)3 ( + ) - 3( 4 0 : 1 )

t

cH2-cHcH2McBr I

l-4"-at"cH-cHz

\1

'StR,

si(cH3)3 (s)-l

c..e ntial

( i . allylo ^\ qem-

cooc2H5

Asymmetricallylboration of RCHO.t (S)-1 reactswith aliphaticor aryl aldehydesor with a,B-enals to form homoallylicalcoholsin92-977oee and80-92Vo chemicalyield. The chemicaland opticalyieldsare higherthanthoseobtainedwith (14,12),with allylboronatesmodified with tarB-allyldiisopinocamphenylborane trates, or with B-allyltrimethylsilylboronates. The high asymmetricinduction is believedto result from stericefiectsrather than electroniceffects. ' R. P.ShortandS. Masamune, Am. Soc.,1ll, 1892(1989).

Alumina Diels-Alder catalyst.t Attempted purificationof I by chromatographyon neutralAlrO, resultsin an intramolecularDiels-Alder reactionat 20'in 83Voyield. The product (2) is verrucarol,a typical mycotoxicsesquiterpene.

0c:H5 HrC

o

CH, Alror, 20'

€

H,Q

83%

"{: trrmethyl. I t() give h()rolane

10

O'(2'Aminobenzoyl)hydroxylamine

h

^TtHrtl:tlir.

of usedfor protection of phenols'tr-Butvlgroupsareoften involvinga

comm-onlyremovedby a reaction variouspositionsof ut"n"t,-und are effectde-/-butySurprisingly'AlCl' alonecan /-butyl acceptorplus " l-"*l' acid'

r'(

I 1

l a t i o n o f p h e n o l s u t ' o o t t " t p e r a t u r e i n n i t r o m e t h a nthan eorm e t hofy laepara-gtonp' nechloride' that group occursmore readily Removalof an ortho-t-butyl ExamPles: OH (cH3)3c

C(CH3)3

Arcrl ctt.cl", , 25' .

'

1 lqo

2\ t i

\a

l

c(cH3)3

c(cH3)3

t

c(cH3)3

(cH3)3c

I I

I

(cH3)3c

I

rN. LewisandI. Morgan,Syn'Comm''lt' 1783(1988)' Aluminum(Ill) iodide' reagent effectsdeoxygenationof epoxides Deoxygenationof epoxides't Th: which can be isolatedas the 'rans-isomer via an interm"aut" iooJiyOtin (ff':O)' caseof some enect setectivereactionsin the in some cases.This t";;:;;; diepoxides.

AlI3' c,Il6' CH,CN, I hr.

'

10%

All3'8ht

,

9Eo

cH,

I P. Sarmahand N. C. Barua, TetrahedronLeuers,29,

5815(1988)'

O-(2-Aminobenzoyl)hydroxylarnine'

fi'oo*',r,.

\,^NH,

) carvone

O-(2-Aminobenzoyl)hydroxylamine

lcrtitrnof l \ ( \ l \l n g a dc-i-buty;h loride. t/.i-!roup.

11

Preparationfrom isatoicanhydride.r ArtHO-->ArtN.2 Reactionof aromaticaldehydeswith 1 in refluxingethanol containingBF3.O(CrH,),providesthe correspondingnitrile in 78-94% yield. rF. D. Eddy,K. Vaughan J. Chem.,56, 1616(1978). andM. F. G. Stevens, Canad. I P.S. N. ReddyandP.P.Reddy,Syn.Comm.,lE,2179 (1988). (SADP). (S)-(- )-1-Amino-2-(1-methoxy-1.-methylethyl)pyrrolidine

(*\l -.". CH.

( l ) . b . p .6 5 " / 4 . 5 m m .0. D - 1 5 . 4 "

t

HrN

l

ocH3

Hantzsch dihydropyridine synthesis.tThe original Hantzschsynthesisrinvolvescondensation of two equivalents of a keto esterwith an aldehydein the presence of ammonia.In an enantioselective version.rthe chiralityis introduced preparedfrom 1. The by use of a chiral hydrazone(2) of an alkyl acetoacetate anionof 2 is then treatedwith Michaelacceptorsto form adducts(3), which cyclize (4), in 64-727ooverall yield and in 84-98o/oee. to 4-aryl-1,4-dihydropyridines R'OOC\

*'oot). vrr3 #nt-'oo .",4f ,i ciroxides 4/i\ -lsomer 3 ,,i some

cHrAg t

n^rr I

Jii,:!l:.<x1.,

?t"'

64-12% oveterl

O't-c", (s)-2 Ar

C:n one

R'oocv,I\./.cooR2 l l cocH3 A* ..,-, v'r3 I

gCH,

(*)'fCH,.".

Ar t " R'OOCv,i\./COOR'

ilrl CH.

N H

CH,

4

\_J 3

D. Enders,H. Kipphardt,P. Gerdes,L. J. Br€na-Valle.and V. Bhushan,Bull. Soc.Chim. (1988). Bels.,97,691 A. Hantzsch, Ann.,215,1,72(1882);A. Singerand S. M. McElvain,Org. Syn.,Coll. Vol. t . 214 (1943). D. Enders,S. Mtiller, and A. S. Demir, Tetrahedron Letters,29,6437(1988).

Ammonia-Acetic acid

Ammonia-Acetic acid. Tetracyclization.TheHeathcockgrouplhasdescribedaremarkablyshort andefrcientsynthesisoftheskeletonoiDaphniphyllumalkaloids(2)by.reaction o f t h e d i a l d e h y d e l w i t h g a s e o u s a m m o n i a a n d t h e n d i s s o l u t i o n i naaand c e t ithe cacidat precursorto 1' The azadiene 70". The yield is 77Vo,baledon the diol The conversionof a to b is an imine b have both been isolatedand identified' The tetracyclizationmay well be inintramolecularDiels-Alder type reaction' (3)' of aitatoiassuchas DaphnilactoneA volvedin the biosynthesis

("un'

.lr afil

thE

cu afl blt

G

.t

ne I !{

o _ c6H5

C!

o

_

c6H5

c

Ammoniurn formate-Palladium catalvst

a"ut'

' .hort iSctlon lcld at nJ the ) l\ an

f'c in-

l R . B . R u g g e rM , . S o c 'f.1. 0 . 8 7 3(11 9 8 8 ) . i , . M . H a n s e na,n dC . H . H e a t h c o cAkm

Ammonium chloride. The patent literaturehas describedthe prepDiaryl ketimines,ArrC:NH. with ammonia,but arationof (C6H,)rC:NH by direct reactionof benzophenone further.Actually.a numberof diarylketimines thisroutehasnot beeninvestigated canbe obtainedin >95Voyieldby reactionof a diarylketonewith liquid ammonia and a catalyticamountof ammoniumchloridein THF in a sealedtube at 120"(60 bar). I G. Verardo, (19tt8). 1501 S-tn.Comm.,18, P.Strazzolini, andM. Poiana. A. G. Giumanini,

Ammonium formate-Palladium catalyst. reduction,t Aromatic ketonescan be reducedto the corClemmensen-type respondingmethylenecompoundswith ammoniumformateon transferhydrogenation in aceticacid catalyzedby l0o/oPd/C. The reductionis usuallycompletein can be reducedunder these 10-30 minutesat 110'. Halo and nitro substituents carbonylgroupsare reducedto saturatedcarbonyl conditions,and c,B-unsaturated groups.

HCOONH4,

3#5 c6H5cocH3 C6H5COC6H5 (CuHrCH :

i2%+

CH)'CO

c.u5cH2cH3 (C6H ) 2CH2 l*-

(C6H5CHrCHr)rCO

reagenthas been Use of ammoniumformate as a catalytichydrogen-transfer reviewed.2

14

Antimony(V) chloride-Tin(Il) iodide-Chlorotrimethylsilane

RNor--->filt{llr.3This reductioncan be carriedout by transferhydrogenation usingammoniumformate catalyzedby Pd/C.3The reactionproceedsin 60-90Va yield with completeretentionof configuration. OH

nu nx hc

HcooNH4,Pd/c

?t/\-c,H,--HL t i l i I

ll

i'^ r\v2

\./

(synlanti= l:3.2)

(synlani= l:3.2)

,tl I S. Ram and L. D. Spicer,Tetrahedron Letters,29,3741(1988). 2 S. Ram and R. E. Ehrenkaufer, Synthesis,9l(1988). 3 S. Ram and R. E. Ehrenkaufer, ibid.,133 (1986);A. G. M. Barrettand C. D. Spilling' Leuers,29, 5733( 1988). Tetrahedron

Ammonium nitrate-Trifluoroacelic anhydride. This reaction can be effected with the relatively safe combiN-Nitration.t nation of NH.NO. and (CF,CO)'O in nitromethane at 0'. NO,

H

(*)Fo rI#%rl:ro \J

\J

?

A

-\_i?

o"N--_A-..-NOu

n\_-i* ^a --

I S. C. SuriandR. D. Chapman. (1988). Synthesis.743 SbCl., SnI,, Antimony(V) chloride-Tin(Il) iodide-Chlorotrimethylsilane,

clsi(cH.).(1). Cyclization of silyloxy carbonyl compounds,t Five- to seven-membered etherscan be obtainedfrom 1-, D-, and e-silyloxyaldehydesor ketonesby silyl

Cd g

ArenesulfenylisocYanates

!cnrtlon Et 9OVc

15

nucleophilesin the presenceof thesethree reagents,the combinationof which is TrSbClu.The silyl nucleophilecan more efficientthan trityl hexachloroantimonate, or cyanotrimethylsilane. be triethylsilane,allyltrimethylsilane,

o tl

f

-

\

-!jlf*-* + (CrH5)3SiH C6H5C(CHr2CHroSi(cH3)3 a

\OAau",

OSi(CH3)3 vsr\v' r3/3

li

H-i1cur;rcHCuHr+ (cH,)rSicN----'-+ | | cuHr. o^cN cis,28Vo trans,537o 1 K. Homma and T. Mukaiyama, Chem- Letters,259 (1989).

rpilling,

Antimony(V) chloride-Tin(Il) trifluoromethanesulfonate. Michael reactions.t This systempromotesa Michael addition of silyl enol ethersto c,p-unsaturatedthiolesters,which are excellentMichaelacceptors'Trityl saltsare lesseffective,as are Lewis acidsin combinationwith SnClr'

osi(cH3)r

o ll

eH- srcl5's(srfh

l-

crlrsMcH,

t""r'i;tt' 'ar"rt

+ crHrsry-"'

3 c()mbi-

sc2H5 CH, = 87:13) (anilsYn

91 (1988)' Chem.Leaers, M. Tamura,andT. Mukaiyama, S. Kobayashi, ATSNCO. Arenesulfenylisocyanates, isocyanate, (1), unlike the stablepentafluorobenzenesulfenyl Theseisocyanates -ureas' or cannotbe isolated,but can be trappedas arylsulfenylcarbamates Example: c2H5scl+ AgNCo '-'-+ [G,HjSNCO]# I 36% HN(cH3h I

tcnlbered s br silyl

o ll

C6H5SNHCN(CH3)2

C6H5SNHCOOCH3

Azidotrimethylsilane-Aluminumisopropoxide

rT. Nagase, (1988). K. Akama,andS. Ozaki,Chem.Letters,1385 Arene(tricarbonyl)chromiumcomplexes. Nucleophilic addition.t The reaction of (anisole)Cr(CO). (1) with givesalmostexclusivelythe LiC(CH3)rCN,followedby oxidativedecomplexation, meta-adduct,regardlessof the reactiontime, the temperature,or the presenceof HMPT. This regiospecificityis not usual, however. The behavior of (naphtha(cH3)rccN

4"\

l) Lic(cH,),cN._30.

KA

2')r"

>

OCH3

Cr(CO,)

4t\

| rl V\OCH3 (m/o= 97:3)

I

I

{ ul F t .l

(2) is more typical.In the lene)Cr(CO),or of (5,8-dimethoxynaphthalene)Cr(CO). latter case,addition of the samenucleophileresultsin both 1,4,5-and 1,4,6-trisubstitutednaphthalene,(3) and (4). In this casethe ratio of 3:4 dependsupon the temperature,the presenceof HMPT or TMEDA, and the cation (Li or K).

Cr(CO), cH. I

ocH3

f",

MCCN,Tr-rF cHr

-J|'

MCCN, THF

2

4

\

CH"

CH,

q(cH,)rcN

t -

ccN

I

CH, Cr(CO,\ 3

cH3o

Cr(CO), 4

'E. P.Kiindig,V. Desobry, Am. \oc.,111,1804(1989). D. P.Simmons, andE. Wenger, Azidotrimethylsilane-Aluminum isopropoxide. 2-Trimethylsilory azides.t This systemreactsrapidly with epoxidesto give carbon.The productsare trimethylsiloxyazidesby attack at the less-substituted precursorsto azidohydrinsand B-aminoalcohols.

(

Azidotrimethylsilane/Trifl uoromethanesulfonicacid

HOH"C

3{ir}* 1 / + (cH,),siN, ' )v% o

\\ltn lr the rccof r h th a -

ln the .t'-triupon

Kr.

) glve t\ are

"o"'"\-to'*' (cH3)3sid

I M. Emziane, (1988). andD. Sinou,Synthesis,541 P.Lhoste, Azidotrimethylsilane-Trifluoromethanesulfonicacid. Aromatic amination.t Electrophilicaminationof arenescan be effectedwith a reagentpreparedin situftom N.Si(CH.).' tetrachloroaluminate, aminodiazonium yields are obtainedwith aminodiazonium Higher AlCl., and hydrogenchloride. prepared in situ from N.Si(CH.), and F:CSO.H in the triflate, NHTN2.OSO2CF;, are >90Vcfrom arenesthat are not aminoarenes Yields of presenceof the arene. groups. The isomerdistributionis typicalfor deactivatedby electron-withdrawing electrophilicaromaticsubstitutions. G. A. OlahandT. D. Ernst,"/.Ors.,54,1203(1989).

Lr 3 rdSd

cl|"\ Barium ferrate hydrate,BaFeOa'HrO(1)' Preparation:NazFeOo+ Ba(NO.), + 1 (dark purple)' couples Oxidation.t This reagentis similar to barium manganate'It also to dithiols converts yield and aromaticaminesto azo compoundsin moderate

CH

sulfidesin 85-1007aYield. rH.Firouzabadi,D.Mohajer,andM.Entezari-Moghadam'Bull'Chem'Soc'Japan'61' 218s(1988). Barium manganate,8, 21;9, 23;10, 16;,12, 38' Aromatic aldehydescan be oxidizedto the correAICHO - A{OOH.r yields30-92Vo' Ali' spondingacid by this reagent(excess)at25-'40' in CH,CI'; conditions' these under phaticaldehydespolymerize rR. G. Srivastava Syn'Comm''18'2193(1988)' andP.S. Venkataramani, anhydride,(CoHrSeO)rO(1)' Benzeneseleninic oxidationofphenols(|0,23-24).'Theearlierreportofoxidationofphenols oxidation to with 1 mainly to o-quinoneshas been confirmed;recent reports of p.quinoneshasbeenshowntoinvolvecontaminationoflwithbenzeneseleninic for this oxidation'Solventsalsocan u.ii, C.U,SeO,H(2), which is para-selective of choicefor 1, and cHtCl, is the solvents the play a role. THF and benzeneare both 1 and 2 areorthoanhydride, In acetic 2. with Leri ,oluent for para-oxidation in oxidationswith both formed be can selective.In addition,phenylselenoquinones of indole' by addition I and 2, but this reactioncan be inhibited rD.H.R.Barton,J.-P.Finet,andM.Thomas,Tetrahedron'44'6397(1988)'

3 chloride,CrH.SeCl(1). Benzeneseleninyl alkenesto Chlorinationr In combinationwith AlClr, this reagentchlorinates aryl to.provide provide vinyl chloridesand chlorinatesarenes,but not benzene, exchlorinated thlorides. Anisole, diphenyl ether, and N,N-dimethylanilineare of combination Brominationcan be effectedby the clusivelyinthe para-position. I with aluminumbromide. Bull' ChemSoc' andM' Kameyama' I N. Kamigata, H. Matsuyama, T. Satoh,M. Yoshida, (1988) . 2226 449, 61, lapan, 1E

Clf'

Benzenetelluilnicanhydride

Benzenesulfenylchloride. Reaction with silyl keteneacetals;epory alcohols.l C.H.SCIreactswith silYl esters(2) with anti-selectivity.The ketene acetalsto give o-sulfenyl-B-hydroxy (CH"),SiO OSi(CH")" c6Hsscr' '---"'-coHscHr , i t f.*rn-14qo CH^/'4O./"2"s i, !()uples tr,'i'to di-

I

?H ?

t",^ro'/"2"s

-/..:',rrr.61.

.IJ

sc6H5 2 = 6-8:94*92) (sYnlanti lnc corre!1 ,. Ali-

60% LtAltl4 I

oH

pBzl

cH.^

l

"

oH11 JzH's' G>[:*", # G

N.1-

s 6 " 3

,*r,f"",

rr:.rctionof r t . r l zr e d b y ra).which

o ^'i",*ix''

. 4e% fY\t" c,H.cHJsu ' -J" ,]

\'

i."' s''.HC'H' OH

(f). The reagentis generatedin situby reactionof 2-Benzoylthio-3-nitropyridine 3,3'-dinitro-2,2'-dipyridyldisulfidewith benzoicacid and triphenylphosphinein CH,CI,. a-Glycosylesterc.t The anomericlithium alkoxideof 2,3,4,5-tetra-O-benzyl(2) reactswith 1 to form mainly an a-glycosylester (3, ct/B = o-glucopyranose l6:1). This reactionis generallystronglyc-selective,even with highly hindered

\arrh alkyln( \uch as , r r rL r l a t i o n .

,r,oa-(9-o\ Bzro\_-a;l coc5H5 3 ( 1 6 l: )

n

N'(Benzyloxycarbonyl)'r--serineP'lactone

a-substitutedcarbohydratecarboxylic systemsand is free from epimerizatigll 1f 2-acylthio-3-nitropyridines' acids.It is applicableto other 'A.G.M.BarrettandB'C'B'Bezuidenhoudt'Heterocycles'2E'specialissue'209(1989)' 1' 109;2' 59' Benzyl chloroformate(clco'cH'c6Hs)' group't Reaction of "' i"iy:t"tycarbonylmethyl Protection o7 u'o'it'-niii with 1in acetonitrile giut' u viscousoil' which reacts the uracil (2) with tottain presence glvo overall yield. Alkylation of 3 in the and triethylamin" ,o uffJJ'3- in

o il

HNry

l i l

:il tagl ril

o tl

F 1,f..Tg.,, HN\F ^'J a r,lr9zttsb , l,l 85%

oAN/

oAN/ H

CHTOCOBzI

f 3

q

" -,*"flI,J,y,i;. o ll

RNfr

l l l o4N/ H

t

o F 4, rarc,

CH.OH,25" 84-1m%

**\'

oA*/

CHPCOBzI

o 4 yield' and generallyin almostquantitative (EDA) occurs. of ethyldiisopropylamine racile' (catalvtic hvdrogenation)is equallv ;;;;;i;;;i"; Letters'1381(1988)' Y' Yamada'andS' Ozaki'Chem' rT. Nagase, K. Seike,K' Shiraishi'

p.

(l)'

N-(Benzyloxycarbonyl)-t"serinep'lactone' VEO BocNH 47voyield by reactionof N-(benzyloxycarbonyl)-lThe B-lactoneis obtarnedin in THF It is stable una'oi.ethyl azodicarboxylate serinewith triphenyrpni"s-piin" hydrolyzedby aqueous for sometime; it is rapidly to air at 25" and can be siored base.

I t

Benzyloxymethylenetriphenylphosphorane

cooH PSC#'J., 47q.1

art o\\'lic

HO^r I-

,Jt3.

1989).

l::CIlOnOf t ( : , )n i t r i l e

n

N-Protecteds-amino acids.t A wide variety of nucleophilesattack this lactone at the B-carbonto provide optically pure N-protecteda-amino acids.The (2) is typical.Thisunusualct-amino preparationof N-Boc-B-(pyrazol-1-yl)-r-alanine acid occursin watermelonseeds.

:ra\ence

ii:!I, r*C^" 4 0 - 1 0 % cfxcooH \-N Eli HNBoc , 'S. V. Pansare, (1989). G. Huyer,L. D. Arnold,andJ.C. Vederas. Org.Syn.,submitted (CoH,).P:CHOBzl (f ). Benzyloxymethylenetriphenylphosphorane, (4).t Carbohydratesin which the ring oxygenis Pseudo-a-o-glycopyranose group are known as pseudosugarsand can have useful replacedby a methylene properties. physiological A new methodfor conversionof c-o-glucoseto 4 involves 2. This ketonereacts to the protected5-hydroxycyclohexanone firstrearrangement uith the phosphoraneI to give the benzyloxyvinylether 3, which on Pd-catalyzed

(l',) # Bzro ]oH

(o',,) n,ro\dH

OBzl

H2,

Pdrc,cHioH ---+ 15E

OBzl

\ lcld, and

rj.l (1988).

.

Ho\-/-;El

65:35 OH

CH" \\' arbonYl)-LIr rsstable b\ aqueous

(oBz'/ Bzlo loH OBzl

-&-cH'

"o7-oF__To, =

OH

OH

A

(S)'o'[N-(Benzylproloytamino)benzophenone

product' Surprisingly'the hydrogenation hydrogenationfurnishes4 as the major major product' the (7) as of e gl-u",a pseudo-p-t--pyranose 'I'C'S' andB' Quiclet-Sire' A' S Machado' I D. H. R. Barton,S D' G6ro'J' Cl€ophax' Chem.Comm.,1184(1988)'

o o l l l l (S)-o-[N-(Benzylproloylamino)benzophenone'(

(l)'

)rcurc'H'cc6H5

N

Bzl This reagentand Ni(NO')' react Schifrcomplet with gtycineand Ni(NOt)2' complex2'' with glycinein methanolto form the chiral

8fi8$;

1 + H|CHTCOOH

lillli rccdcs. ]dcr ri ClI. aatacl.

+ Ni(NOr), -;'

for glyThe complex 2 can serveas a substitute S-Hydrory-a'amino acids'r c i n e i n a r e a c t i o n o f a l d e h y d e s o r k e t o n e s t o p r o v i d e t h r e o -(S)-serine p - h y d r o xiny -800-amlno with 2 provides acids.Thus the reacttonof parafo'maldehyde 98Voee' 2 + HCHo'--'r

complex#HocHrcHCooH NH2 (S)- Serine (897o ee)

P r o l i n e s . 2 T h e c o m p l e x 2 u n d e r g o e s b a s e - c a t a l y z e d ( C H 3 oaNdihydroa)Michaelad-!non"r. Reaclionof 2 with acroleinfurnishes unO a,p_enals to dition to (S)-proline' pyt."f"-Z-."rUoxylicacid which is reduced T' V' A' S Batsanov' S' V'.Vitt'-Y^T' Struchkov' rY. N. Belokon'A' G' Bulychev' andV' M' Bakhmutov' I V' Lysova' A L' Ryzhov' M G' V. A. Tsyryapkin' Timofeeva, Belikov,Am. Soc.,lM, 4252(1985) V A' V' A Tsyryapkin' 2Y. N. Belokon,A. G' etlytiJ"' V'e' Pavlov'.EB Fedorova' (1988)' l'C'S'PerkinI' 2075 Sukh.t,"", andV. M' Beiit

lFt 9l

tetraciloroiodate Benzyltrimethylammonium en.tllon

2 + CH':Q11CHO

: / (-..s.

t"'o^"

' {-\r"OO" --N' Bzl 73qo NaBH3cN J

flrcooH -N' H

6954o ee) I react

Benzyltrimethylammonium dichloroiodate, Bzl(CH,),NCl,I- (1), yellow needles,m.p. 125-126o.The salt is preparedby reactionof Bzl(CH,),N. Cl in waterwith ICI in CH,C! at 25". The reagenteffectsc-chlorinationof aryl methyl Chlorinationof A{OCHyt ketones. r, clclLcllcl

0) ArcocE

3 t()rgly-(r-amino e rn 80-

ch.rcl adJrhvdro-

r,'r. T. V. ;rJ V. M. lrn. V. A.

r#*

A(ocH,cl + Bzl(cH,),Mcl-+ HCI+I,

S.Kajigaeshi, T. Kakinami, Chem. M. Moriwaki, S.Fujisaki, K. Maeno, andT. Okamoto, Letters, 2709(1987); idem,Synthesis, 545( 1988). Benzyltrimethylammonium tetrachloroiodate,(CH.;.NBzlICl, (l), yellow needles, m . p .1 0 6 - 1 2 5 The salt is preparedby reactionby (CHJ,NBzII with CCI,I in CHrCl, (96% vreld). Side-chain chlorination of alkylarenes.t The reagent effects benzylic chlorrnationof alkylarenesin CCL in the presenceof AIBN. The co-productis , C H r ) r N B z l I C l.z -

C6H5C[LCH3 # (C6H5)3CH ;;-

C6I{5CHCICH3+ di- and richlorinated products (C6HJ3CCI

Letters, S. Kajigaeshi,T. Kakinami,M. Moriwaki, T. Tanaka,and S. Fujisaki, Tetrahedron 2 e . 5 7 8 3( 1 9 8 8 ) .

(R)-( + )-1,1'-Bi'2'2'-naphthol

26

(BINOL)-Dichloro' or dibromodiisopropoxytitaniurn

l)' l,l' -Bi-2,2'-naphthol( BINOL' oi'epoxtdel "'ot)''ion Cleavage ona

The aluminum reagent obtained

by

,"u.,ionotinl-r*i*,oi"it'vr-;id*:llt::tT;[fi iT[:Hil?::fii:fiJl the ate complex(' (3) in 407o in reactionswith epoxides'but andlithium butoxide,;;;; ee.

chlorohydrin .f.fon"*"n" o*iO. into the

rIIS lstr 6r( t 0

rad

-30o' mos most of the ' -^t^A "'i+l' I fnr hoursat -30o' treated with 2 for 5 hours When the keto epoxrde4 is completely (4) is 5' but the recoveredketo epoxide epoxideis cyclizedto the acetal hormone(6)' t"t ii" 'fntr'"ti' of ( )-C1u-juvenile resolved,and can ot *"0

fn,

?

"".4,^A.", OJ' -"3

f"' -2,cH2cr2) i *r,$fcu' "

f"f. cH''t-s^cu'

H (R)-4 (>957oee)

I I

T coocH3 CH, (-) -6 4' 4147(1988)' Tetrahedron' I Y. Naruse, T. Esaki,andH' Yamamolo' (BINOL)-Dichloro' or dibromodiisopropoxytitan' (R)-( + )'1,1''Bi'2,2"naphthol formula (R)-la or u totpt"* 1 with the probable ium (1). These reagent;;; (R)-1.b.

(R)-la, X=Cl (R)-lb' X=Br

Birch reduction

n.rl bY a c t r ri t Y

) \lcl, ys Jl\Vo

Asymmetricglyoralateenereactions,t In the presenceof 4 A molecularsieves (MS), methyl glyoxalateundergoesenantioselective ene reactionswith 1,1-disubwhen by la or 1b. The former is superiorin reactions stitutedalkenes catalyzed involvinga methyl hydrogen,whereasthe latter is superiorin reactionsinvolving a methylenehydrogen.The reactioncanprovideo-hydroxyestersin 70-95Voyield and 85-98Voee.

CH. " I cH,

o II

CH, OH " i l | 4AMs'ctlcq > cH.icHrcHcoocH3 + HCCOOCH,

cH,

a r of the nfJletely l 6) .

(A.",

\

R , 9 5 V oe e R, 837oee

727o 87Vo

la 1b

o

^

o

H

(-\ * "X.oo.",----.-.--------82Vo 89Vo

la lb

coocH3

R, 837oee R , 9 8 7 0e e

andT. Nakai,Am. Soc.,l11,1940(1989). K. Mikami,M. Terada,

Xa", Birch reduction. Reductivealkylation. N-/-Butylnaphthalenesulfonamides can undergoBirch reductivealkylation in acceptableyields. The productsundergopyrolysisto alkvlnaphthalenes.'

mZ--/tr-\

l

l

cH3o^AZ

l

l

,

/*

l)BuLi,NHj,t

,--=;-cH3o$1 . n . , l

l

l

CH,-

$O.mr-r-nu

n.sqa

ory-,titan' R)-la or

,

|

l

l

-SO'NH-I-Bu

^

./\

t i l l "\/Y

cHso

CH, resultsin tetrahydro Birch reductionof phenanthreneor 9-alkylphenanthrenes yield by LilNH. in high but 9,lO-dihydro derivatives are obtained Jerivatives, (equationI). group :eductionof phenanthrenes by a 9-trimethylsilyl substituted yield group quantitative with BuoNFin of L can be removedin The trimethylsilyl

ZE

Bis(acetonitrile)dichloropalladium(II)

houn r:E.l rn€th

R = H, CH:, CzHs

is obtained THF, but if an alkyl halideis present,a trans-9,7}-dialkylphenanthrene (equationII).'

cH.c \tl

c2HsI, BU4NF

(II)

22Vo

78Vo

Reduction of benZocyclobutenes.sBirch reduction of l, available from rnprovidesthe enone2 after hydrolysisof the intermediate. hydroxybenzaldehyde, This enone is a usefulprecursorto the cyclobutanemonoterpenesgrandisol(4) and lineaton(5).

o

rrth ; .\tl r rdrE

(cH3)2culi ) E3% W'

lifsil"',a(a' is%

I-f"A' 4=2

!i.l

+__/

a.--l

v t

2

|

cis-3

9H,

rl}|

OH

CH, 4 I L. GottliebandH. J. E. Loewenthal (1988). Letters,29,4473 , Tetrahedron ' P. W. Rabideau (1988). ibid.,29,3761 andZ. Marcinow, r T. Kametani, T. Toya,K. Ueda,M. Tsubuki,andT. Honda,J-C.S'Perkin1' 2433(1988)' Bis(acetonitrile)dichloropalladium(II). Rearrangementof allylic acetates.t This Pd(II) catalysteffectsrearrangement at 25" in 0.5-2 to (2E,42)-l"acetoxy-2,4-dienes of (1E,42)-3-acetoxy-1,4-dienes

I t l r :r fr ata

(R)-Bis-(l,l'-binaphrhalenyl)2'2'-diselenide 29

hours in 90-96Voyield. This catalyzedrearrangementfavors formation of the (2E,42)-l-acetoxy-2,4-diene. It is the last stepin a synthesisof the acetate(l) of methyl cr-dimorphecolate.



r H Sano,T. Takeda,and T. Migita, Chem.Letters,119(1988).

(1, BINAP) (R)- and (S)-2,2'-Bis(diphenylphosphine)-L,l"binaphthyl Asymmetic hydrogenationof allylic alcohols (14, 39-40).' Mammalian dolwhich are involved in glycoprotein ichols (2) are terminal dihydropolyisoprenols synthesis.They contain one terminal chiral primary allylic alcohol group. The polyprenols3 presentin plantscorrespondto dolicholsexceptthat they lack the terminaldoublebondconsideredto be (Z). They canbe obtainedby hydrogenation and (S)-1, which affectsonly of 2 catalyzedby (bistrifluoroacetate)ruthenium(Il) the terminal double bond to provide (S)-3in >95Vo ee. CH"

CHrr

Asymrsc alkaloidscan alyzedbv Pd(

,,..,-r'*f;1"r."*,

l--

--i-cHCHroH--=;;: (CHr)rC: CH'(CH,C:CHr) "CH; (Z) 2 . n = 1 3 -1 5G + Z )

9H,

9H,

t i (CHr)rC: CF!(CH,C: CHr)"CH2CHCFLCH2OH (S)-3 (>957o ee) Asymmenichydroboration.2 Hydroborationof alkeneswith catecholborane catalyzedby Rh(COD)CI'2BINAP or [Rh(COD)CI],'2DIOP and followedby oxidation providesoptically activealcoholsin 20-157oee; Rh-BINAP systemsare than Rh-DIOP systems. somewhatmore enantioselective

*>-F,

--------r . 2DroP,-25' tRh(coD)cll -25" tRh(coD)cll.28INAP, C"H, |

cnf\cu,

--------t

l_-\__,_l

DIPAMP. and most efiective practicalroutc J. P.Generar

llJ-Bb(@.r riftorooellr Preparatio

L R , 2 R , 5 7 7 oe e lR,2R,64Vo ee

C^H, I' .\-oH

cH3

R , 2 7 7 oe e I B. Imperiali and J. W. Zimmerman,Tetrahedron Letters,29,5343(1988) 2 K. Burgessand M. J. Ohlmeyer,J. Or9.,53,5178(1988).

/ \ (C.tLLP" . \

ll,2rBis(diphenylphosphono)ethanelcyclopentadienyl(iodomethane)ruthenium triflate

(2S,3S)-(- )-Bis(diphenylphosphino)butane [(S,S)-Chiraphos],

(c6H5)fdrFdrnlcuttr;, (L). Supplier: Strem. I H"C

n r . r i i a nd o l lr ctrprotein g r ( ) u p .T h e rcr i.rck the lr,rgenatton .rtlects onlY

I CH"

Asymmetric cyclization to tricyclic ergolines.t The ergoline systemof ergot alkaloidscan be obtainedin fairly high enantioselectivity by cyclizationof 2 catalyzedby Pd(0) complexedwith a chiral ligand and a base.The ligandsBINAP, AcOCH' NO' I l -

\ t\

CH. NO' l " t i

ht

t

t

z \ - . { ' .\)l g lo*" ;',A 'l t 4 t I ll \-AN'

ll ) \,4:,r'

H

H

2 + (-)-f, DME,KF 287o + (-)-1, TIIF,K2CO3 62Vo

rr,

3 'll%o er 667oee

{cH:cH2oH

lcihtrlborane l('\\cd bY ox) .\:ttlfflS

&f€

DIPAMP, and Norphosprovide3 with someenantioselectivity (26-47Voee). The most effectiveligand is I in combinationwith KF, but the yield is low. The best practicalroute to opticallyactive3 is the useof I as ligandand K,CO. as base. J. P.GenetandS. Grisoni,Tetahedron (1988). Letters,29,4543

[ 1,2-Bis(diphenylphosphino)ethane]cyclopentadienyl(iodomethane)ruthenium nifluoromethanesulfonate, Cp(dppe)Ru(ICH1)triflate (l). Preoaration:

cF3s03cH3 CHrClr ----€ ,Ru. (cuHr)rP_1_)P(C6H5)285Ca I I )

o -f-

Ru (cuH,),P\_l)P(C6H5)2 cF3so3ICH3 I

36

Bis(1,1,1,3J,3'hexefluoro'2-propyl)hydrogenphosphite

enaminesand enolates as well as C-Methylation.r This triflate methylates other nucleoPhiles.

(*)

cH,CrrO

A

*r$

r\,u'*z \_/

\-/

t

\,/

Dcd xdcs. rhE parrcl cont

o

oLi ,\

l.6Bi(-

*1#

t

€nsrtuzct!

,\.cu,*z

\-2

o \

7' 1891(1988)' Organometallics' rR. J. Kulawiec andR' H Crabtree'

RCOS

r

o

hydrogenphosphite(1)' Bis(1,1,1,3,3,3'hexafluoro'2-propyl) PreParation:

}r Ot.dr

ff

l - ? ltY,l:;l':il:tJ cH1cL''" ) rcr,+(GH,),COH lCt,$"J

!,+lti{2

deoxyusefulfor preparationof protected Phosphonylation'' This reagentis for synthesisof phosphonates(2)' which can be used ribonucleoside-3-hydrogen deoxyribonucleotides'

:ca{cnl l. ROE artcnrtc 'C,H.r,C n o-ard : \rrb,

DMTrO

n.o,,DMrro Jutt llla,?,,,*,

Hfl

80-90%

7

Lerters'1675(1988) I H. Takaku, S. Yamakage,O Sakatsume,and M. Ohtsuki, Chem'

.ITL' !Lpoe 9: o{ ti r\. BrCl, iI u l{' fcr! rccr H grtu"

Bismuth(lII) chloride F\l.rlc\ aS well aS

1,6-Bis(dimethylamino)pyrene,

Decarboxylation.t This reactioncan be carried out via N-acyloxyphthalimides,which undergolossof CO, when irradiated(350-450nm) in aqueousisopropanolcontainingt-BuSH (proton donor) and 1, which servesas a sensitizer.other sensitizers are lessuseful.

o

RCOJ.{

\--.,+. .^r-{/

RH

+ (r-BuS),

Q2-98qo)

?t$Vo)

II

o

( 169 8 8 ) . K . O k a d aK, . O k a m o t oa,n dM . O d a A , m .S o c . , 1 f 0 , 8 7 3

o .cr{()i.PH . rnm

l:

'-*fi "'o , l. + r-BuSH

..r nrotected deoxyl\i\i l()r synthesis of

2.{-Bis(p-methoxyphenyl)-1,3-dithiaphosphetane-2,4-disulfide (Lawesson's :eagent). ROH --->RSH.t This transformationcan be effectedwith this reagent(1) in :noderateto high yield. The yield is quantitativein the caseof triphenylmethanol C-H,)3COH],but somedehydrationis observedwith tertiary alcoholspossessing :n a-methylor c-benzylgroup. (1989). I Nishio, J.C.S.Chem.Comm.,205

o

.'..y'" r -o

/

Ft\{(crH5)3

: . : : , ' r ' .1 6 7 5( 1 9 8 8 ) '

Bbmuth(III) chloride,BiCl,. Aldol reaction.t Silyl enol ethersreact with aldehydesat 25oto give aldols : the presence of BiCl, (5 mole %).The classical version(Mukaiyama,6,590i.lt of this reactionusuallyrequiresa full equivalentof TiCloas the promotor. lhe BiCl. versionpermitsuseof ketonesas well as aldehydesin reactionscarried ui at 25o,but a longer time is requiredand yieldsare only moderate(20-65Vo). !i.rh versionsshow only slight diastereoselectivity. iJ Ohki,M. Wada,andK. Akiba,Tetahedron (1988). Leuers,29,4719

33

Bis(pyridine)iodine(I)tetrlnuoroborrle

Bis(1,3-propanediamino)copper(Il)chloride' H, H" /-N.. ' c,.u ','N--\

(

\-1.r'' A,

t'NJ

.,

c

l]cntc ) 2cr (1).

I ntram oI ecuI ar cycI i zlt molecular cyclization of b pounds. It also effectscydi

H2

and oxiOxidative coupling of hydroquinones't Oxygen can effect coupling presenceof this dation of hydroquinonesto biquinonesin 50-75Voyield in the complex.

oH | ^ _ -

ll'i:.lyLi l2)cHru | I|

7,-

l=/n.,

o.

,^

r[-f""''"'3ij,!oo", 't5% "{}RCHzOH.T Primary alkyl bromidesor iodides react with these :'*o reagentsto give the corresponding primaryalcoholsin moderateto high yield. C)ptimumratiosfor this reactionare (Bu,Sn),O/Ag/halide= 2.2:l.l: 1.0. Alkyl

40

1,1-Bis(trimethylsilyl)ethylene

chloridescan be precursorsif first treatedwith NaI (3 equiv.).The reactionis not usefulin the caseof secondaryhalidesbecauseof elimination' sio2 q

AgNO3 @u3Sn)2O,

RCH2X

ot'rp'zo-so't [RCHroSnBur)#;

RcHroH

rM. GingrasandT. H. Chan,Tetahedron 279(1989)' Letters,30,

'M. Kira,T. Hioo 6939(1988).

Bis(trimelhyklyll Electophilk reagentsaffords t actionwith vinvl (

C6F,I[OCOCF.],(1)' [Bis(trifluoroacetoxy)iodo]pentafluorobenzene, This hypervalentiodine reagentis preparedby reactionof cuF I with trifluoroaceticanhydride. oxidative cleavageof alkynes.t This reagent(3 equiv.) cleaves1-alkynesto acidsin 55-80% yield. norcarboxylic the org.,53'6124(1988). lR. M. Moriarty, andI. Prakash,J, A' K. Awasthi, R. Penmasta, (1). 1.,1-Bis(trimethylsilyl)ethylene of Li in THF with 1 leadsto the l,4-dianion Reaction Peterconreactions.t in 96Voyield. This dianionreactswith (2\ of 1,1,4,4-tetrakis(trimethylsilyl)butane canbe convertedto 4 by brominationwhich 3, 1,S-diene to form paraformaldehyde bromodesilylation.

[(cH,),si]rc:cH, #I*

Oxidation ot br bis(trimethyls rncreasedby use r

q

[(cH3)3si]racH2cHrclsi(cH3)31' , ,ro | """o

{

(cH3)3si

l) Br2

l

J# CHr: 611CS,CH'CH:CH' l

l

Br

Br

4

4

%

si(cHJ3 l

CHz:CCHzCH,C:CH, 3

4 results The dianion2 can be alkylatedas expected.Reactionwith dihalosilanes (equationI). in silacyclopentanes

This transform fonvloxaziridine(i ri accompaniedb1 a-Ily&or-t a theseacidsor anit Frund in 30-0q ;rclohexanoneor

L Camici.P.Dcrd F A. Davis.G. Sr \l Pohmakotrand

,ISi(cH:)r]z

( I )2 + H r S i C l r # I

SiH.

Y 'Isi(cH3)3]2

lir{Eirnctbylflyl)

'cH,),siol: cFs .4rcmartcly/

Bis(trimethylsilyl)peroxide/Trifluoromethanesulfonicacid 4l l€ reaction is not

toH

'rlI l-F.l with trifluo-

'M. Kira, T. Hino, Y. Kubota, N. Matsuyama,and H. Sakurai,Tetrahedron Leuers,29, 6939(1988).

Bis(trimethylsilyl)peroxide,[(CH,)3SiOlr,l1-, 67; 12, 63. Electrophilic hydrorylation r Reaction of this peroxide (1) with Grignard reagentsaffordsthe correspondingsilyloxyderivativesin 70-90Voyield. The reactionwith vinyl Grignardreagentsresultsin silyl enol ethersor c-silyloxyketones. OSi(CH")" -"

MgBr |

RC:CH,

j*

C6H5CHO,

|

ricr{

nC:Cu.

57%

o o H

i l l

> RCCH2CHC6H5

to :are: 1-alkynes ; s - l . 6 1 2(41 9 8 8 ) .

t., lhe 1,4-dianion trrntonreactswith r{ f'r bromination-

Aa"st',

aV

(/

(-,1-osi(cH3)3

-;

oxidation of vinyllithiums.2 vinyllithiums are oxidizedto silyl enol ethers bv bis(trimethylsilyl)peroxide(1) with retentionof configuration.yields can be rncreased by use of bis(t-butyldimethylsilyl) peroxide(2). l) rBuli

H,,,1:

(E)

(z) (z) Sr CH), {.C:CHu I

Jrh.,Iosilanesresults

z)r*z

coHr\,r'Bt I I 2

,

llvo l87a 35Vo

cu4AroSiMe'R (8, 100%) (2, tw%) (2, tn%)

This transformationcan be carried out by oxidation with ( + )-camphorylsul:,'nvloxaziridine(13, 64-65) followed by trappingwith ClSi(CH.).,but this route . accompanied by partial inversionof geometry. a-Hydroxy carborylic acids or amides.! Reaction of the dianion (LDA) of ':cse acidsor anionsof amideswith I providesthe corresponding o.-hydroxycom:uund in 30-60% yield. The reagent fails to hydroxylate the lithium anion ot :5ctohexanoneor of e\t phenrj\acetate. (1988). L. Camici, P.Dembech, A. Ricci,G. Seconi, andM. Taddei, Tetrahedron,44,4197 :F. A. Davis,G. SankarLal, andJ. tVei,Tetrahedron (1988). Letters,29,4269 l{. Pohmakotr andC. Winotai, (1988). Syn.Comm.,18,2141 Bis(trimethylsilyl) peroxide/Trifluoromethanesulfonicacid, cH,)rsiolr/cF3SO.H. Aromatic hydroxylationt This reaction can be effectedin moderateyield

A

3!'-Bis(triphenytsilyl)binaphthol-Trimethylaluminum

s(cJrr\

(11' 256)' A more effective with30VoHrO, in combinationwith HF/BF3 etherate activatedby triflic acid' and convenientreagentis bis(trimethylsilyl)peroxide

l>^

(1989)' I G. A. OlahandT. D. Ernst,"/' Org'' 54,1204 Bis(trimethylsilyl)selenide,[(CH)3Si],Se(1)'' The reactionof diunI ntramolecular v + 2lcyiloaddition of selenaldehydes.2 saturatedaldehydessuchas2withl.inthepresenceofacatalyticamountofBuLi givesselenaldetryaes(a)whichundergointramolecularDiels_Alderreactionsto 3 in modestyield' give selenabicyclics

(-'ln*-K."'qCH, 3 = 65:35) (cisltans

2,n=3

J' Orq',47'1354(1982)' rPreparation: M. R. Detty,andM. D' Seidler, (1988)' ' S. MuraiandN. Sonoda Letters,29,6965 Tetrahedron ,

S(CJT\ (R)-r (l) C6F5CHO +

clq

(lI) CI3CCHO+ Ctq:q

' K. Maruoka.Y. Hoshino.T. Shirrd ( 1988).

Blue tetrazolium,L, 61. Oxidation of stcroid enou,.l zolium (1) in an alkalinemediumI Other examples:

R 1,2-Bis(trimethylstannyl)'1'alkenes, lCUr;rSn>C:CHSn(CHr\

4

(1)'

by addition of The reagentis obtained, solely or mainly, as the (Z)-isomer benzylic, allylic, with couples It Pd(0). by hexamethylditinto 1-alkynescatalyzed of replacement by selectively BzlPdCl[P(CuH,)J, or aryl halidesin the p."r"n." of on halogen by replaced also is C, at group the C,-Sn(CHr),group. The stannyl reactionot (Z\-l with NIS or NBS.'

CH.'Y- s

I CrH
RCoocHt This conversioncan be efiected by oxidation of aldehydeswith Br, in cH.oH via.ahemiacetat (efuation I). The methodis appricabre lo optically pure aldehydesobtained from'ruga.s. yields are moderate in the reactionwith aromaticaldehydes. r

(r)RCH. "cH,oH[n"J+,_u-Rcoocq

48

(EF(2-Bromoethenyl)diisopropoxyborrne

This reactioncan be extendedto primary alcoholsand to uic-diols,both of which can be oxidizedto aldehydes.2

q*oH cH,+d cH'

oH I [o '"T,'4'"?f'o, 'n,o" ' ------ 'l| **J"o.r. l*J" 84% l-'--o^^coocH3 \

Preparation:

Bt-,4sn

(E)-1,3-Dicncs. h a vinylzinc chloride to f the presenceof a bar (

i

CH.IO -

CHt

CtL:C/S " \

(ao+ 17')

A HO

NrIo' > [".-O-""J

#

z

"",oo.0coocH3

OH

rD. R. Williams, Letters,29, E. E. Allen,F. W. Lichtenthaler,Tetrahedron F. D. Klingler, 5087n988). 2F. W. Lichtenthaler, (1988). P.Jarglis,andK. Lorenz,Synthesis,790

BuAzo Bromine fluoride, BrF. BrF is convenientlyformed from Br2 in CI.CF and used directly. Aromatic bromination.r BrF readily undergoesboth ionic and radicalreacradicalreactionand permits tionswith arenes,but additionof C2H5OHsuppresses electrophilicbromination.Simplearenesgivemono-and dibromoderivatives.BrF is more usefulfor brominationof deactivatedarenesas shown.

(E)-(2-Bromoetheny of I to couple alkylzirr rhis reagentis unsatisfrc

S. Hyuga,N. Yamashim C6H5CN-II-

nr-BrCeHnCN + o-BrCuHoCN (81Vo)

C6H5CHOd

(r0%a)'

$Bromo-9-phenyl[roru

m-BrtaH4CHO

rS. Rozen,M. Brand,and R. Lidor, J. Org.,53' 5545(1988)

"t\4u(o-t-Pr), (E)-(2-Bromoethenyl)diisopropoxyborane

(1).

N-Protected c-crdr trdes can undergoraceu rrth a phenylfluorenyl(F .aen to silicagel. A tni

9-Bromo-9-phenylfluorene

oth of which

Preparation: ut-.^r"rr+

(cHr)rcHot

1, b.p. ?3./12 mm.

#

(E)-1,3-Dienes. In the presenceof ClPd[P(CuH,)J,this borane reactswith a vinylzincchlorideto form an intermediatethat coupleswith an alkyl chloridein the presenceof a base(LiOH) to give an (E)-1,3-diene.

,r*J"a,""r,

!.oo.",

s(cH3)3 CH':Ct'". Letters,29,

,

CoH,

E,99%

BuAzncr +coH,cHpt +F ,('F and used I r.rdicalreacn .rndpermits I n \ . r t i v e sB.r F

-a>

CA-'"H' 8,96%

(E)-(2-Bromoethenyl)dibromoborane, BrCH:CHBBr2, can be used in place of I to couple alkylzincchlorideswith an alkyl chlorideto form a monoene,but this reagentis unsatisfactory for couplingof alkenylzincchlorides.' S. Hyuga,N. Yamashina, S. Hara,andA. Suzuki,Chem.Letters,809 (1988).

l Bromo-9-phenylfluorene,

N-Protected a-amino aldehydes,t Boc- and Cbo-N-protecteda-amino alde:rdes can undergoracemizationunder usualsyntheticapplications,but protection rrth a phenylfluorenyl(PhFl)groupprovidesconsiderable configurational stability, .\en to silicagel. A typicalpreparationis shownfor N-(PhFl)-r--alaninal (2).

N-Bromosuccinimide r, N(C2H5b,

lgl%!gg' CH3CHCooSi(cHJ3

cH3cHcooH l;-' Nttpnrl

NH,

/\ O

r) LiArH4

I

\

)

= 1Y " cr,gH-8u -t cH"cH-[-N'o)+% "."T'._ ew. _ LJ rMii\_cHo NHPhFI -u^^' (667o overall) \r'

Y*

i".

(2) is readily N-Protected s-amino ketones'2 N-(-Phenylfluorenyl)alaninal ketones(3) by reaction,ofa Grignard convertedto a variety of N_phFl-c-amino NCS and S(cH3), (corey-Kim rewith reagent(excess)followed by oxidation OH

'e#- t"'-Aru l

"

Ncs s(cH:h,g11" soso y

O I -Bu N}IPhFI

NUpnn

reaction,whereasa protectingctbr can be used for regioselective@u[ pentenylCtFo pling a 2-benzylated iodoniumperchlorate(f0. 212-:l: benzylatedpentenyl glycoside as are then replaced[ | dissacharide endwith the z-pentenylanomencq to give a trisaccharide.

D. R. Mootoo,V. Date,andB. Frrr andB. U. Udodong. P.Konradsson,

Bromotrimethylsilane.This silam anhydrousNaBr in dry DMF at I Silyl enol ethets.t Reaction , BrSi(CH:).and triethylamineresu ally the (Z)-isomer. Examples:

3

agent).Deprotonationandalkylationoftheseprotectedct-aminoketonesoccurs a'-alkyl branched of diastereomeric at the a,_carbonatom,o p.ouia" a mixture followed by methanol in a_amineketones. These ketones on hydrogenolysis enantiomeric high in acids periodateoxidationgive c-alkyl substituiedcarboxylic purity.

r)KHMD.

3 ;i;;;i, cltvL*# ?

I cH'

I PhRNH n

l]ti

o

".'

ovqu

? E cHscctLcH'o lt

cH3ccH2cooc

ll

"o\* crl 'R)-5 (997oee)

o ll

HCCHTBu 1;

Am' Soc''109'236(1987)' rW. D. LubellandH. Rapopoft, ' ldem,ibid.f10' 7447(1988)'

I

I

S. Ahmad,M. A. Khan, and J. lqbc

N-Bromosuccinimide. B) with glycosides("itl"::,:t Deglycosidation-t Treatment of n-pentenyl N B S i n l , T o a q u e o u s a c e t o n i t r i l e r e s u l t s i n l i b e r a t i o n o f t h e a n o m e ror ichydroxyl results in a glycoside a digroup. Brominolysis in the presenceof an alcohol protected benzylic or ester groups are not saccharide(in the caseof sugar-oH.) benzylic ether group on c, slows this affectedby this brominolysii a protecting

t3R)-Butane-l,3-diol, *{ aluminumhydride reductionof g nch. Fluka.

(3R)-Butane-1,3-diol

t{

\-cHo CH, (2) is readilY )u..::rrnal rcr.tron of a Grignard ('Il I (CoreY-Kimret)

Agu illP:.Fl

51

reaction,whereasa protectingether group haslittle effecton the rate. This effect can be usedfor regioselective couplingof glycosidesto a trisaccharide. Thus coupling a 2-benzylatedpentenyl glycosidewith a 2-acetylatedpentenyl glycosidewith iodoniumperchlorate(10,212-213) resultsin a disaccharideformed from the 2benzylatedpentenyl glycosideas the glycosyldonor. The acetyl groups of the dissacharide are then replacedby benzylgroups,which now activatethe reducing endwith the n-pentenylanomericcenterin glycosidation with anothersugaralcohol to give a trisaccharide. I D. R. Mootoo,V. Date,andB. Fraser-Reid, Am. Soc.,ll0, 2662(l9gg);D. R. Mootoo, P. Konradsson, U. Udodong,andB. Fraser-Reid, ibid.,lf0, 55g3(19ggi. Bromotrimethylsilane. This silanecan be generatedin situ from clSi(cH.), and anhydrousNaBr in dry DMF at 25". silyl enol ethers.t Reactionof carbonylcompoundswith in sl/u generated BrSi(cH:). and triethylamineresultsmainlyin the thermodynamicsilyl ether,usually the (Z)-isomer. Examples:

_1

o-rmrnoketonesoccurs mcnc a'-alkYlbranched rn(thanolfollowed bY id. rn high enantiomeric

o

Brsi(cHr)3,.N(c2H5r !s(c4;,

ff

cH3ccH,cH3 +i-

cH,\cH' I

H ( Z / E= 9 : r \

?

?si(c*)3

CH3CCH2COOCTH, ffi-

CHr\H

cooc2Hs (E/Z=r0o:0)

,-^--..,-,Pt I CH, -S 99% ee)

?

HicH,Bu -*

?Si(C::L

n\Bu

H (ZlE = 94:.6\ S Ahmad,M. A. Khan, and J. Iqbal, Syn.Comm.,U, 1679(19gg).

de. reither0 or P) with ( :hc anomerichYdroxYl t: rr .i qlycosideor a dic ,,: cstergroupsare not ir irtrup on C2slowsthis

?"

rJR)'Butane-1,3-diol, cur cHrc4oH (r). Thediorispreparedrby lithium ruminumhydridereductionof poly(3-hydroxybutyric acid),available from Ald:ch. Fluka.

52(2s,4s).N-(,.Butoxycrrbony|)-4.(dicycrobutylphosphine).2.[(diPheny|phosphino)methy|]pynolidine

The acetal 5-Atkyl-3r5'dihydroxypentanoicacids; chiral hydroxylactones'2 1,3-bis(trimethylsilyloxy)-1with (R)-1 couples (2) of an aldehydeformld from methoxy.l,3.butadiene(3),togiveasingleisomer(a).Thechiralauxiliaryis ,cH3

o--0.5 :i J6

lhc report presents evidence E r(,npolar solvent and that | :JJrtion in polar solvents. I H S Kezar,J. Org.,6,2920 .39 :ll7 (1988).

gH COOCH3

t\. .

-.

endo-2

t

l

l

+

Z\./-..COOCH3

l

l

l

\AAcoocH" coocH360:17

l

exo _2

major adductsin the ratio 60:17. This result contrasts with the thermal reaction of 1 at 110'with the samedienophileto give 2 as the only adduct(3r% yierd)brt rn an endoI exo ratio of 1 :4. Another exampreof the valueof this methodis shown in equation(I).

Butyllithium

l,A.{on(oot' (r)ll | |

,u'

\ZacuH,

oLil

o

Jf,,

L l l . ' d16qc "--

I

coH,|o-snaq

Loi,",l \

thiumsis the reactionof lithium napbt

//

{ i i H CuHt

4 BrrCCHrOSiR, I, R, = 1-Sqg11t

= i-Pr3

r.nor*,

56Vo

r) 2 LDA 2)c2H5oH r HC=cosiR. 96%

3

,

617o

\o"t*

o

Dehydrobromination,3 One approach to trialkylsiloxyalkynesinvolves dehydrobrominationof L, preparedfrom tribromoethanol,with BuLi (2 equiv.) to form (Z)-2-bromovinylsilyl ethers2, which can be convertedby LDA followedby alkylationinto siloxyalkynes(4). Theseproductsundergocycloadditionwith vinyl

-cH. ,t'"'\

anti-SeIect iv e I2,3lW i t ti g rcant4l (silyloxy)allylethers (1) provides thc regardlessof the geometry of the dout

9"' .

a,'1.rzosiC(Ctlt)i t l

o---l

.

cH,

CoHt I (UE\ = 7r:29 = 93:7

,o-r*-rrrr"oo cHt J 2)

cH3c=cosiR3 4 (5) to produceresorcinolderivatives ketenes(a), generatedfrom cyclobutenones (6).

t"'J,-ro

CH,

&sio

R/S,R=CHzOMOM

I K. Tanaka,I. Funaki, A. Kaji, K. Mior 7l8s (1988). r W Choy and H. Yang,J. Org.,53. 5'796 r R. L. Danheiser,A, Nishida,S. Savarie ( 1988). 'C. A. Broka and T. Shen.Am. Sac..lll 5 E. Nakai and T. Nakai, Tetrahedron La

CH, a

6

Cyclization of a-alkoxylithiums.a A usefulroute to tetrahydrofuransinvolves lithiation of (tributylstannyl)methylethers. Another useful route to c-alkoxyli-

I Butyllithium-Hexamethylphospbork a Nitroalkane dianions. Seebach with BuLi (2 equiv.) and excess HM reaction with benzaldehyde to form I reversed, addition of nitroethane to a dianion is formed as shown by reacti ratio of 3:4 is controlled by HMPT. lt Similar results obtain with l-nitroprop

Butyllithiun-Hexamethylphosphorictriamide

-JfH' /

coH,fotsnBu,

--JCH'

oo"r,

tou'

/

\

cun,i\o2 = ll:1) (cisltrans

thiumsis the reactionof lithium naphthalenide(LN) with a-(phenylthio)ethers. ,CH" { i : H CoHt

SJ/ asc,u, -11* 52sa

\o"{*

(_,

rr.,,rralkynesinvolvesdeil *rrh BuLi (2 equiv.)to rr:cJ bv LDA followedby with vinyl 3., -r cloaddition

n

,.CH.'

\ot* = 7:I\ (translcis

anti-Selectivelzr3lWittig reatrangements(cf., 12, 60). Rearrangementof a(silyloxy)allylethers (1) providesthe silyloxy 1,2-diol with high anti-selectivity regardlessof the geometryof the double bond of L. QH"

I

",.aott*, =--+ ^-oit.tcD,,#l!i,. cH,

!- ttC:COSiR:

d--l

3

-^ (^ coHt

Ho'

boH, I (7,/E)= 71;29 = 9t:7

du.c resorcinolderivatives

t

737o SlVo

antilsyn= 82:18 77:23

lK. Tanaka,I. Funaki,A. Kaji, K. Minami, M. Sawada,and T. Tanaka,Am. Soc.,ll0, 71850988). r W . C h o ya n dH . Y a n g ,J . O r g . , 5 3 , 5 7 9 6( 1 9 8 8 ) . r R. L. Danheiser,A. Nishida,S. Savariar,and M. P. Trova,TetrahedronLetters,29,4gll-

( re88).

'C. A. BrokaandT. Shen,Am. Soc.,flf,2981 (1989). ' E. NakaiandT. Nakai,Tetrahedron (1988). Letters,29,5409 ('tl, +

R SrO CH,

o :r: r.rhvdrofuransinvolves [.

ryf rgj r.", (+)-2,m.p.151-154o

(-)-1,m.P.112-114o

RC=CH

+ BurSnH 4

R = ccHs R = AcOCHT R=s(cHil

913 ?lt 9lt

K. Kikukawa,H' Umekawa,F ftdl

Crrbonylhydridotris(tripherylf q Regi oseIecti ve hYdrofottY ld it (Z)-t-butyldiphenylsilylalken of essc is group silyl bulky A rionI).

(r)

t-BuPh,Si -

\J

Br

This reaction can be used to obtail

( (ID &si-

/

Carbonylhydridotris(triphenylphosphine)rhodium

6)

These are the first reagentsknown to effect enantioselectivefluorination of is observedin the enolatesof carbonylcompounds.The highestenantioselectivity reactionof (-)-1 with a B-ketoester(equationI). , Thc chiral tridendate s hrghh enantioselective r.zrnc addsto arYl and ! re.

o (r) (

a

t) N!H,cthq

ii

il

zit->i ,

,A.-coocr4



%$J

e

"cooc'u'

\--'/

00% ee) I E. Differding 6087(1988)' Letters,29' andR. W. Lang,Tetrahedron ClRh(CO)[P(C.H5)3],(1)' (Carbonyl)chlorobis(triphenylphosphine)rhodium, adds spontaneouslyto hydride Tributyltin Hydrostannation of l-alkynes.r Howtrans-l-alkenylstannanes. and of crsmixture terminalalkynesto form a 1:1 provides (2, galvinoxyl) inhibitor radical and a ever, use of this rhodium catalyst as the major product. 2-alkenylstannanes ..-CH:CH,

-,cHr1.cH, , >96q e€ 5 -,\rl.

r l . i n d 2 a r e prepared

ii+ Rc=cH + BurSnH R = CcHs R = AcOCHz R = Si(CHJc

R )c:cHr* BurSn

RCH:CHSnBur 7E:22 73:27 16:24

99% 7l% 9L%

(W = 9l:9) (E > 99) (E, |ffiVo)

Chem.Letlers'881(1988)' F. Wada,andT' Matsuda, H. Umekawa, K. Kikukawa,

;h.,,rrde.

,\F

RhH(CO)[P(C,H,)3]. (l)' Cerbonylhydridotris(triphenylphosphine)rhodium, hydroformylation.t The rhodium-catalyzedhydroformylation Regioselective is an excellentroute to p-silyl aldehydes(equaof (Z)-r-butyldiphenylsilylalkenes tion I). A bulky silyl group is essentialfor this regiocontrol.

tH

(r)

sulo;*

,si t-BuPhzSi

,Bu +

6ffi

CHO

|

CHO

-L -

+ RTSiCHCH RTSiCHTCHBu ,Bu 96:4

This reactioncan be usedto obtain aldols(equationII).

(ID

&si. -

oH

\J..",i'

cHo

R3sicH,J"q".", ' ,r* --------l;-

+

(98:2)

70

Cerium(IV) smmonium nitrate

Hydroformylationofthel,2-bisilylalkene2isaccompaniedbyBrookerearrangement to provide a silyl enol ether (3)' R.Si

-si1cH,;,

**

R3SiCH2r Y

2

Oxidative demethylation of tetranet with CA 1,4,5,S-tetramethoxynaphthalenes electron is an R If products (equation I).

/OSi(CH')3

3

'M.M.Doyle,W.R.Jackson,andP'Perlmutter'TetrahedronLetters'30'233(1989)' Cerium(IV) amonium nitrate (CAN)' of CAN for oxidativeaddition Addition of l,!'diones to vinyl acetate't Use ofcarbonylcompoundstoalkeneshasbeenreportedinseveralpatents.Themethod can be extendedto synthesisof acyl or alkoxycarbonylfurans' O ll

O ii

JCOCH3 / \

cH,cN__ r)cAN, ___

cHYcH,+

cHr:csoRc4Ej4'

o o il il nAAocrH,+

JcooczHs -ll cHr:cHoAc-;- (o2\

n.o4elcn,

mainly;but if R is an electron-withdrarin of quinonesare stableto CAN, but can t or with AICL.

^

ASO-.Oi lGl

o

o

a\ I

I,R=H R = CHzOH R=CHO

I

+CH,CH:CHOAc-30%+

/\-_ir'"'

cH:

cHfo

substitutedo-position.Thismethodissuperiortoanearlieroneusingl,_Cu(oAc), in HOAc (10,211). L, CAN cH,oH, ?5' $Vo

r r O A r''-9tN Y ll ll -+ BuecHrI PrcHccH3+ eodcH" ' t v w l 74:26

sz.t

o/

Yieldsarelowerwithpropenylacetatethanwithvinylacetate,butevenso,the (last example)' reactionis a viable route to monoterpeneevodone g-Iodinationofketones.zIodineincombinationwithCANconvertsketones with substitutionat the more into c-iodo ketonesat 25-50" in HOAc or CH'OH'

| I

53*

R=H R = CHzOH

Atot

3.W,

R = cHo

43t

4-Oxo aldehydedimethyl acctols'' and CAN resultsin a radical speciesthe svlethyl)ketone. Solvolysisin methano aldehyde.Similarreactionsof ketones$t orovide1,4-diketones(6' 356)' Sulfuxides.s Oxidation of sulfidcsr equiv.)in CH,C!/HrO catalyzedby Bu.l type rearrangementdoes not occur und

Cerium(IV) ammoniumnitnte

xJ mpaniedby Brooke rearrange-

Oxidative demethylation of tetramethoxynaphthalenes.sDemethylation of 1,4,5,8-tetramethoxynaphthalenes with CAN (in HrO) can lead to two types of products(equationI). If R is an electron-releasing group, quinone2 is formed

osi(cH3)3

\=J

R

lc'-

cAN cHlcN, 25' -----+,

: , ' , , tL e u e r s , 3 0 , 2(3139 8 9 ) .

t ..- : CAN for oxidativeaddition }(:: j .:r:er'€t?lpatents.The method Ea:-.rrliurans.

_JcocH3

c-\ lt

//

.-.J!r,

//

\\ \\

;.--------.--eco46^cu,

't 'l}Vo 'l5Vo

I,R=H R = CHzOH R=CHO

3 13Vo 857o

group,quinone3 is formed.Both types mainly;but if R is an electron-withdrawing of quinonesare stableto CAN, but can be demethylatedwith AgO-407o HNO. or with AlCl,. OH

-TCoXrHt )\

7l

./

^ A8O-40% HNO3 Z +

o

'

l

/-'r-----..cH..

l

l

l

R=H R = CHzOH

53Vo 52Vo

at'^'60/ rrl acetate,but evenso, the .-tslexample). r qith CAN convertsketones ',\rrhsubstitutionat the more f rrlier oneusingIr-Cu(OAc)2

Alcl3 cHrclz 3

R = CHO

) l

fii

l -

o l

BuCCHtl

,

43Va

4-Oxo aldehydedimethyl acetals.4 The reactionof a ketonewith vinyl acetate .rndCAN resultsin a radicalspeciesthat is convertedto an a-(2-acetoxy-2-nitro.r'lethyl)ketone. Solvolysisin methanolresultsin the dimethyl acetalof a 4-oxo rldehyde.Similarreactionsof ketoneswith isopropenylacetateandMn(III) acetate (6, 356). provide1,4-diketones Sulfoxides.s Oxidation of sulfidesto sulfoxidescan be effectedwith CAN (2 equiv.)in CH'CI,/H,O catalyzedbyBurNBr at 25"(90-100Voyields).A Pummererdoesnot occurunder theseconditions. :\pe rearrangement

Cerium(III) chloride

CH2OH

*H,, . cH,:s11eo. A L&.",Kd o u,r, f.",o", cHrcH(ocH3)'

Puc,Bt(so.)! |

*or--% + CeCl"

metal catalyst.In fact, Ni(CN)r is inr affectsthe rate of reaction. Tetrabuql: methylammoniumbromide are the rnos N(C

I E. Baciocchiand R. Ruzziconi,Syn. Comm.,18, 1841(1988). 2 C. A. Horiuchi and S. Kiji, Chem.Letters,3l (1988). 3Y. Tanoueand A. Terada,Bull. Chem.Soc.lapan,61' 2039(1988). . E. Baciocchiand R. Ruzziconi,J. Org.,51, 1645(1986);Org. Syr., submitted(1989). 5 E. Baciocchi,A. Pi€rmattei,and R. Ruzziconi,SYn.Comm.,18' 2167(1988)'

Cerium(III) chloride. Functionalized allylsilanes.l A Grignard reagent when activated by CeCl. reacts with esters,r ester acetals or lactones2to give functionalized allylsilanes'

? " 1

'8Pi::i{&:', coH,cH:cHCooc2H5 L ,, ^,,:CHCICHzSi(CHr)rlrl LC6H5CH

c6H5cH2cl * 69

crdlr

B. A. Narayananand W. H. Bunnellc. Ic syr?.,submitted1988. :T. V. Lee. J. R. Porter, and F. S. Rodco. ' R. Oi and S. Tanenaka,Chem. Lettcn. ll" ' L Amer and H. Alper, Am. Soc.,lll. 9g?

Cerium(IV) sulfate, Ce(SO)r. Malonyl radicals.r Thiophenes a rreated with a dialkyl malonate and ceri ro involve oxidative generation of malo tO-85Vo.

9l% | SiOz' -HOS(CH3)3

' ""^

il'

:CHCCH2Si(CH3)3 C.HTCH

.",/)+

cH,(coocHJ'=

z=O, S

(cH3LSicItMect+ o\

CH"

ll'

./> )

r*'

HocH,(cH,),ccH,si(cH3)3

L. M. Weinstock,E. Corley, N. L. Abr.. n.2627 (1988).

+ CcCl3 747o oxygenationof ru-hydroxybenzyl A{HrOH'--> A|CHO,s Platinum-catalyzed presentin traces'the further is also If CeCl: 3. 2 and alcohol(1) givesa mixtureof possibly by acetalizationof 2. depressed, oxidationof 2 to 3 is markedly can be effectedwith cobalt reaction This Carbonylation of benzyl chloride.a conditions.CeCl promotes phase-transfer under carbonylor a palladium(0)catalyst nickel(Il) cyanideas the use of permits the also processand this phase--transfer

Cesiumcarbonate. Wittig-Horner reactions.t Ttrc rc (1) with aldehy&sI methylphosphonate yields when NaH is t poor gives and proceed readily at (F. $opropyl alcohol r synthesisof o-erythro-C's-sphingcir

Cesiumcerbonate

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

""-q;,,cuoH

+ CeCl,

'\\ l.

| '- ,::nt uhen activatedbY CeCl. allylsilanes. r t .- :unctionalized

o l

H

l l

il:CHClCHzSitCHr)Jrl

3 (18Eo\ lVo

c6H5cH2cl * 66 -c'edaH'fBi

c6H5cH2cooH

B. A. Narayananand w. H. Bunnelle, TetrahedronLetters,g.626r (19g7):idem, org. S_yn., submitted1988. 'T. V. Lee, J. R. Porter,and F. S. Roden, Tetrahedron Leuers,29,5009(l9gg). R. Oi and S. Tanenaka,Chem.Leuers,ll15 (1988). '1. Amer and H. Alper, Am. Soc.,lll,9Zj (1989).

Cerium(IV) sulfate, Ce(SOo)r. Malonyl radicals.r Thiophenes and furans undergo substitution at c, when ireated with a dialkyl malonate and ceric sulfate at 25.. The reaction is considered :o involve oxidative generation of malonyl radicals by the cerium salt. yields are tt)-85Vo.

-Hos(cH3)3

CH"

il-

It{.C t'l :CHCCHTSi(CH3)3 CH"

cli

2 (7rEo) 88Vo

cooH

Ni(CN)r,CeCl'

F r 6l - l'r ( 1988). r rrr. Srr., submitted(1989) I -.' . lt.2l67 (1988). r':"r

n.,.'.

""C-t"o*Ho

metal catalyst.In fact, Ni(cN), is inactivein the absenceof cecl,, which also affectsthe rate of reaction.Tetrabutylammoniumhydrogensulfateand cetyltrimethylammoniumbromide are the most efficientphase-transfer catalysts.

L-

ll'

cH10H. H'O

cHroH. A

/n'.--cHrcH(ocH3),

ll-:

PVC,Biz(sOrb

^

+u.+

il'

cH.):ccHrsi(cH3)3

EJ rrqenation of rn-hydroxybenzyl I l\ -,.\,,presentin traces,the further is:^ : .1 acetalizationof2. r.i.i:,rn can be effectedwith cobalt r!:.:^-ir'r conditions.CeCl, promotes lht ':.c' of nickel(Il) cyanide as the

ll

cH/{-)

\

cc(soah. cHloHr.r,o . $ffi4 /tr + cH,(coocH,l, "",4r\cH,(coocH3),

z = O ,S L M. Weinstock, E. Corley,N. L. Abramson, A. O. King,andS. Karady,Heterocycles, n.2627 (1988't.

Ccsiumcarbonate. Wittig-Horner reactions.t The reaction of 1,2-O-isoproylidene-o-glyceroylnethylphosphonate (l) with aldehydesfailswhenN(CHrCH3).-LiCIis usedasbase rnd gives poor yields when NaH is used. However, reactionswith CsrCO, in sopropyl alcohol proceedreadily at 0". This Wittig-Horner reaction was used for r svnthesisof o-erythro-C,r-sphingosine (2).

74

Cesium carbonrte

.CH.

cH3+( 9

(cHphsq (cHrhc.

cs,co,

?

"ff

* c,3H2?cHo $1o"",y, #

o

H

O

O

C

Iqco3,64 hI. CsrCOr,15 hr.

I

H 3 c ,CH' < _9 .

r/ l O.-A.,,1,,C13H27

ll o

NH, s"qa srcps, Ho-.,\r1.,CnHzr

r

o

H

I t4c 94*

I T. Yamanoi,T. Akiyama, E. Ishida,H. Ab€. I 335(1989). r J.-F. Lavall6e and P. Deslongchamps,Tetrahcd r R. T. Winters,A..D. Sercel,and H. D. H. Slx

2 Anionic polycyclization to a steroid.2 When treated with CsrCO., 2-meth(1) and the Nazarovreagent2 undergoa Michael reoxycarbonylcyclohexenone actionfollowedby aldol condensation to give a tetracyclicadduct(3), which under(TsOH) to give the steroidderivative4 in 477ooverall goesdecarboalkoxylation yield.

I). Desilylation of I with CsF and L8-cro*n

$i(qrl ),

o

tl //'\.8

l

Cesium fluoride. 2-Aza-L,3-dienes.t A new route to th + 2lcycloadditions involves protodesilyb [2 as 1, available in several steps from propar!

l

l

I, E = COzCHT

+ cooc(cH3)3 )

(l) H2NCH,C=CH +

Cs2CQ, cHch,25'

nrNSHCH:Ot

cooc(cH3)3 3 lr* | r.ou, c5rq,,

ovqal

J

A

resultsin (E,E)- and (E,Z)-2 in the rario ol increasedthe (E,E)/(E,Z) ratio approach

4

Alkylation of cesiumphenolates.s Alkylation of hydroxylated 9,L0-anthraquinonescan be accomplished fairly readily by alkylationof cesiumphenolates.

Crotylization of RCHO.' (E)- and ( hydesin the presenceof CsF to give anarespectively, with high diastereoselectirir

Cesium fluoride

CI

o

HO

75'

(cH3ohs02 (CHrbC . -=O >

H

O

O

C

rqco3,64h. 15hr. CsrCO,,

fH' o--r\.,1zc"H' I OH

I 84Vo 947o

' T. Yamanoi, T. Akiyama,E. Ishida'H. Abe, M' Amemiya'andT Inazu'Chem'Letters' 33s(1989). : J.-F.Lavall6e Letters'29'6033(1988)' Tetrahedron andP. Deslongchamps, 712(1988) 'R. T. Winters, Synthesis' andH. D. H. Showalter, A. D. Sercel,

7

teJ \\lth CsrCO.,2-methr ! undergoa Michael rer rJJuct (3), whichundercrrr.rtive4 in 477ooverall

Cesiumfluoride. 2-Aza-lr3-dienes.tA new route to theseusefulsubstratesfor [4 + 2]- and such of N-1-triethylsilylallylimines involvesprotodesilylation [2 + 2lcycloadditions (equation yield as 1, availablein severalstepsfrom propargylaminein about 30Vo of water I). Desilvlationof I with CsF and 18-crown-6in THF containinga trace si(c2H5)3 (t) HrNCHrc=cH #

4Nlncn:cH,

c'H'cHo ' cuHrcH:N CHCH:CHz si(c2H5)3

o

r, (8,rN%) I csF. l8-qown-6 80% rHF (H"o) |

.-+ | rsox, ceite'

r.au

I

A

crHryr: I-

q\ -CH,

H 2' (E' EtE'Z) = 6: I

of wateris resultsin (E,E)- and (E,z)-z in the ratio of 6:1. As the concentration unity' the (E,E)/(E ,Z) ratio approaches rncreased

{ f nr JroxYlated9,10-anthralr..: ,rf cesiumPhenolates'

crotylization of RCHO.' (E)- and (Z)-crotyltrifluorosilanesadd to aldealcohols, hrdes in the presenceof csF to give anti- and syn-p-methylhomoallyl with high diastereoselectivity. respectively,

76

Cesium fluoroxYsulfate

o'H !

CH"

RcHo+'*--r,r"

'

#*Tc*r,

I, C2H5OAc

BucH:cHz-#

BucH-c$

OSO,-C

cH.

(98-9:2-l)

gH crF

RCHO+ CUr^SiR

77-96%

BuCH-CH

I oso:o

r R-

CH, (90-D:10-1)

a,^1.a,OSO,-Cs'

I 'S.-F.Chen,E. Ho, andP.S. Mariano, (1988)' Tetrahedron,44,7013 2M. Kira,T. Hino,andH. Sakurai,Tetrahedron (1989)' Letters,30,1099

\.r'

l l + r - - . . . . r 1| \

cH3cN,0o crHroAc

Cesiumfl uoride-18'Crown'6. Fluorodcstannylation. BurNF is the most reactivesourceof F-, but is difficult Harpp and Gingras' prefer csF to obtain anhydrous.For fluorodestannylation, This reagentcombineswith diorganotin with a catalyticamount of 1.8-crown-6. oxides,sulfides,or selenidesto liberate the correspondinganion, which can be alkylatedto give ethers,sulfides,or selenides. (BurSn)rO+ 2BzlBr ff

@tr)rO + 2Bu'SnF

[(cHr)rSn]rs + 2CHr(CHr)rB,#

t(cH3(cHr)5lrs+ 2(CHr)rSnF

catalystfor conversion is alsoan effectivesolid-liquidphase-transfer 18-Crown-6 of benzylbromideto benzylfluoridewith CsF.2 rD. N. HarppandM. Gingras, (1988)' Am. \oc.,1f0,7737 2M. GingrasandD. N. Harpp,Tetrahedron 4669(1988)' Letters,29'

Cesium fluoroxysulfate, CsSO,OF (1), 10, 84-85. Caution: This hypofluorite is explosive. Addition to alkenes. Although this reagenthasbeen studiedmainly for elecvic-fluoroalkyl trophilic fluorination,rit does add to alkenesto give cls-selective The adductscan be addition. for azfi-Markovnikov preference sulfateswith some (CrH5)3O'BFq-'2 with by reaction ethoxysulfates convertedinto fluoro

F cis-2 529o 30%

' E. H. Appelman, andR. C. Tho L. J. Basile, : N. S.Zefirov,V. V. Zhdankin, A. S.Koz'mrn '14.65OJ(t andS. V. Romaniko,Tetrahedron,

Cetyltrimethylammoniumbromide (CTAB Williamson synthesisof phenyl al\I t alkyl halidesin 20VoaqueousNaOH cont to form phenolicethersin 85-9'lVo vieldCTAB. This procedureis not usefulfor prc and alkyl halides.Instead,the alkyl chlond are heatedin THF at 70"with NaOH (l o CTAS

+ CrHrBr C6H5OH # (CH3)TCHOH + n-CrH,,Ct{ 4, 6677(19881. B. Jur5i6,Tetrahedron,

Cetyltrimethylammoniumchromele, n-C. obtainedas a yellow-orangesolid b1'rcrt rum bromide in water at 25". lt can be u ketonesin an aqueoussolution.Howere

Cetyltrimethytammoniumbromide

OH Crf :-K

- -,A.--rA. I |

I, C2H5OAC

BuCH:CHz-#G-

e- - H -a .

BuCH-CHrF+ BuCHF-CHroSorCs* osor-Cs*1:2

cH3 (9E-99 :2- l)

soia| 1crxr;.o'nro-

*

9H

k-T"rrcH3

B uCH-CH,F

+ BuCFIF-CHTOSO2OC2H'

oso2ocrH5

t 9 0 - 9 9l:0 - l )

f-\ It- ll Lt .'

-ttl-1

I (1988).

a,1-oSo,-Cs. ll+l-------+l

- { f . 1 0 9 9( 1 9 8 9 ) .

I. 28- SnF IrCil CH,),lrS + 2(CHr)rSnF

+ffans_2

cis-2 cH3cN,0o crHroAc

ll :: j.:r\e sourceof F-, but is difficult Dr. iirrpp and Gingras' prefer CsF I r. j!.:lt combineswith diorganotin c. -':.r'ondinganion,which can be

|

\-t'

52Vo 30Vo

30Vo 20Vo

E. H. Appelman, L. J. Basile, R C Thompson, Am. ioc..f01,3384 (1979). ' N. S.Zefirov, 1! V. V. Zhdankin, A. S.Koz,min, A. a. FainzitUerg, A. A. Cakil,e. I. Ugrak, andS. V. Romaniko, Tetahedron,44,6505 (19gg). Cetyltrimethylammonium bromide (CTAB). williamson synthesisof phenyr alkyt and diarkyl ethen.t phenors react with alkyl halidesin 20voaqueousNaoH containingl equiv. of this surfactantat g0" lo form phenolicethersin g5-g7% yield. There is no reactionin the absenceof crAB. This procedureis not usefulfor preparationof diatkylethersfrom arcohols and alkyl halides.Instead,the alkyt chloride,alcohol, a traceof water, and crAB are heatedin THF at 70. with NaOH (2 equiv.).

pa:i. r .: rrnsfer catalyst for conversion

F

r .-.

C6H5OH + CrHrBra1HI8+ C6H5OC2H5

I 19:.69(l9gg).

(CH3)rCHOH * n-crn,,ctJIffL\, a-\
97Vo)-

I S. L. Buchwaldand R. B. Nielsen.Am. \oc..111.2870(1989). tS. L. Buchwald, Fang,and S. M. King,Tetrahedron (1988). Leuers,29,3445 Q.

Chlorobis(cyclopentadienyl)methylzirconiu-, cpTr(CH'

(1).

PyrrolesJ This zirconocenereactsin THF with a lithio trimethylsilylprimary amine,RCHrN(Li)Si(CH,)r,to form 2, which is not isolatedbut allowedto react with variousalkynesto form azametallacyclopentenes 3. Thesemetallacycles, which neednot be isolated,reactwith carbonmonoxideto affordpyrroles4. Yields are

RI

:.opS-*L .CH,

)

%-[.ry**]

s(cH.)"

I

l-"*

t - -

I + RCH"I\,I-Li

,

J-.{.o,o(o

I

I

n'c=cR"

3 Rt

Rt

lt \

!ai.:r: to a ProtectedProPargYlic li. :i\l zirconocenecomPlex(3). bc :,' providean intermediate(a) O::rcallv activesubstratesundergo

OR

4

\*t* H 4

Rt

R2

#

CO, THF NH,CI or 4AI\,!S 30-10% ovqdl

\={ / \ cprZt.*AR

I

si(cH3)l 3

highestwhenthe reactionis carriedout in THF in the presenceof NH.CI (3 equiv.) at 25oor of 4-A molecularsieves.The report includesa rationalefor formationof rather than pyrrolinones.Even acetylenecan be usedin this synthesisto o.v"rroles provide2-substitutedpyrroles.1-Alkynesreactto form 2,4-disubstituted pyrroles. The yield is low in a reactionwith a 1-trimethylsilyl-1-alkyne becauseof steric factors.

12-

bx cH,

S.L. Buckwald, M. W. Wannamaker, andB. T. Watson, Am. Soc..llf,776(1989).

i:.J

a"raa_{ .-----, ll O 55 Ya",a", 4 (90Voee)

Chlorobis(cyclopentadienyl)titanium(III), CprTiCl. Prepararion.' Cyclization of epoxyalkenes.2 The reaction of 6,e-unsaturatedepoxideswith i equiv. of CprTiCl in THF resultsin cyclizationto cyclopentanemethanols. The :eactionis compatiblewith keto and nitrile groupsbut not aldehydegroups.

Chlorodicrrbonylrhodium(I) dimer

fr, rio-1-'cHz'

{

----cr

a""'

'V'

"4"

*I:.

(E = COOqHs)

f"o'"'''

c*ltrans = 8 5 :1 5

.",if,

expansionof the optically pure azind 937o yield. Carbonylationof racen l-men [CODRhCI],in the presenceof chemicalyields.This asymmetricindu S.Calet,F. Urso,andH. AlPer.Am' h

CIB(C,H.): ( I )' Chlorodiethylborane, AUilic diethYlboranes.t These t and 2-alkenesby metalla cycloalkenes lowedby reactionwith 1. The producr alcohols(3), which can be converted

CH,

r1KcH2s(cH3b 2) l. ethq

HO1

t

/CH'

88%

H I t) 2CDrTiCl

63% lztr., HOI

,,M.. \ t

w

(endolexo = 9:l)

..'CH't

)

H

rL. E. Manzer, (1982)' Inorg.Synth.,2l,84 8561(1988)' 'w. e. Nug.ntanOi' V. RajanBabu' Am' Soc',110' Chlorodicarbonylrhodium(I)dimer' of aziridinesto Carbonylation of aziridines(12, Il2)'t This ring expansion is substituted ring the when only p-lactamscatalyredby [(CO)rRhCl],is successful group' The t-butyl a by by an aryl group and when the nittog"n is substituted C^H.

CuHt

\-

'N'

I

c(cH)3 (s)-1

*co$' "n

)_l ohN-c(crtr),

(s)-2

Chem.2 J. Organomet. \f. Zaidlewicz, Generatedfrom Hg[CH,Si(CH,).1;and

o il

c-Chloroethyl chloroformate' CICI Review. Use of chloroformat Braun reaction)has been reviewed rction.

c-Chloroethyl chloroformate

Cp,

-ttH" f.,,,",

t'"HricrcP'

83

expansionof the optically pure aziridineL resultsin the pure (S)-B-lactam2 in 93% yield. Carbonylationof racemic 1 catalyzedby either [(CO),RhCl], or ICODRhCI],in the presenceof /-mentholresultsin opticallypure (S)-2in25-30Vo chemicalyields.This asymmetricinductionresultsfrom kinetic resolution. I S.Calet,F. Urso,andH. Alper,Am. Soc.,Ul, 931(1989). Chlorodiethylborane, CIB(CrH,),(1). Allylic diethylboranes.t Theseboranes(2) can be preparedfrom 1-methylcycloalkenes and 2-alkenesby metallationwith trimethylsilylmethylpotassium2 followedby reactionwith 1..The productsreactwith acetaldehyde to form homoallylic alcohols(3), which can be convertedinto ct,B-and B,1-unsaturated ketones.

H OH

r^.a t l

CHp(CrHs),

r) cHrcHo 2) OH 12% ovarll

\-/

t

t

CH"

l

cHffi \-J

,

3 ro*Jrocor,rr O

(/

'-c1cHr;, S'-1

CH,

v)#

M. Zaidlewicz, J. Organomet. Chem.,293,139(1985);Synthesis,70l (1988) Generatedfrom Hg[CH,Si(CH.).],and potassium.

o tl

\_

O

*AA ^.-."44 (,

i l ." \ \ ) .

rnr erpansionof aziridinesto llr *hen the ring is substituted NtcJ br a ,-butylgrouP.The

CH"

c-Chforoethyl chloroformate, CICOCHCIC\, L2,IL2-I13. Review. Use of chloroformates(carbonochloridates) for N-alkylation (von Braunreaction)has beenreviewed.'Cyclization/dealkylation is alsoa usefulrerction.

E4

3-Chloro'1'hydroxytetrabutyldistonnoxone

Chloromethyllithium. Homologation of boracyclanes.t Chlo for one-carbonhomologation of boracyclan

Examples: C^H.

t-"

I,

(crH5)rN(CIt)4-COOH

socL

,\ ( -------r / + CICHIi I '

/ \

\

-P-

!,N(CH3)'

o

coH,.Jt'f-cH,+ y

(C2H5)2NCH2CHr'\J

c^H. fl " '\,A^ (cH3)2N(cH2)2{j{-c'Hs

82%

/

\

I OCH3

B-

T

OC

1

(l) is convertedto boraoctane2 in 82Vcvie ro synthesisof l2-memberedboracyclane dichloromethylmethyl ether (5, 201-2021 nones(3).

3:l

sax].

: (c2H5)2N(CH2)4CooH (*Ao

H. C. Brown,A. S. Phadke,andM. V. Rang

I CrHt 1 (1988). J. H. CooleyandE. J. Evain,Synthesis'

Chloroform. Reimer-Tiemann formylation of phenols.t Yields in this reaction can be inper creasedby use of solid, powderedNaoH and addition of water (2 equiv. phenol).

iodide (l ). ?. 2-Chloro-1-methylpyridinium (I mmunosuppressant r-F K-sffi (2). :emblescyclosporinA, a macrocyclicpollpl to transplantation,but FK-506v responses rhesisof (-)-FK-506 has beenachievedb The cyclizationto a carboxamidewas carr under high dilution in SlVo yield. The mo of a three-ketosequenceat Cr, Cr, and Ct 11Ouu

G*

fiLt?i5t?;, **.$* d;"" 1 (617o)

cHro

2 (141o\

rA.Thoer,G.Denis,M.Delmas,andA.Gaset,Syn'Comm',lE'2095(1988)'

o ClSn(Bu)1O-Sn(Bu)'OH (1)' The re3-Chloro-1-hydroxytetrabutyldistannoxane, dichloride.It existsas a dimer' dibutyltin of agentis obtainedby partialhydrolysis catalystfor tranesterian efficient Transesterification.r This distannoxaneis phenolsin refluxing or of alcohols ficationof methyl or ethyl esterswith a variety of functional variety wide a toluenein high yield. Sincethe conditionsare neutral, observed. not is groupsis toleratedand racemizationor isomerization Letterc,n,2383(1986)' l J' otera,T. Yano,A. Kawabata, andH' Nozaki,Tetrahedron

1//o

HO la

ocl 2 T K. Jones,S. G. Mills, R. A. Reamer.D S h i n k a iA, m . \ o c . , 1 1 1 ,1 1 5 7( 1 9 8 9 ) .

2-Chloro-1-methytpyridiniumiodide

E5

Chloromethyllithium. Homologation of boracyclanes.r chloromethyllithium is an efficient reagent for one-carbonhomologationof boracyclanes. Thus B-methoxyboracycloheptane

\\ r / o CuHr,A -N-c.H.

Y H - CH,I,N(CH'L'\J

'82% /+clcH"Li----+l

T

ocH3

I

\^

r

l"','=lT",'t 14% )

ocFI, 2

-

\

I )

Y

o

3

(l) is convertedto boraoctane2 in g2voyierd.This homorogation can be extended to synthesisof l2-memberedboracycranes. Reactionof the productswith o,edichloromethylmethyl ether (s, 20r-202) providesthe corresponding cycloatkanones(3). 'H. C. Brown,A. S. Phadke, andM. V. Rangaishenvi, Am. Soc., f10,6263 (1938).

\ :.Jr in this reactioncan be in| : . i . r : i r o fol f w a t e r ( 2 e q u i v .p e r

- ilc4

\:/

2-Chloro-1-methytpyridinium iodide (1), 7, 110;g, 95_96. Immunosuppressant ( - )-rr-s06 (2). This 23-memberedlactone-lactamresemblescyclosporinA, a macrocycric polypeptide,in that they both inhibit immune responses to transplantation,but FK-506seemsto be more active.The total syn_ thesisof (-)-FK-506 has been achievedby a processresearchgroup at Merck.r The cyclizationto a carboxamidewas carried out with Mukaiyama'i reagent(r) under high dilution in 8Lvoyield. The most unusuarfeature of 2 is the presence of a three-ketosequence at Cr, Cr, and C,6(hemiketal).

VoH

2 (r4%) ":-r . lt.2095(1988).

h b- -O-Sn(Bu),OH(1). The rehrr .::;hloride.It existsasa dimer. a:. :iicrent catalystfor tranesterioi .,..oholsor phenolsin refluxing Gu::.:..a widevarietyof functional iz.r:i,'nis not observed. t?:,-,:..1 nn Letters, 27,2383(1986).

T. K. Jones,S. G. Mills, R. A. Reamer,D Shinkai,Am. Soc.,111,1157(1989).

E6

N-Chlorosuccinimide

m-Chloroperbenzoicacid. Oxidative contruction of glycalsJ Reactionof 3,4-dihydro-2H-pyran(1) with benzeneselenenyl chloride and then with methanolprovidesthe adduct2, which is oxidizedby zr-chloroperbenzoic acid to the ring-contracted aldehyde3 (cf..,12, 120).Applicationofthis sequence to the tribenzyl-o-glucal (4) furnishesthe adduct l) c6H5secl 2) CH10H, N(CrH-'cHo I

-l I

\ / ,^-1

| I

ezto'

'oBzl

I

||

(\'oH,lcuH'

\^/tt

ll

I

o I

I te.s% |

8tt'n'

,#

'' -',,v'l =14 I

I

3

o"-

Y

Y

*o-(o> --4" C\' rr \J toH o

7 precursorto nJ: 6. a convenient ! "..:::rde 6 canalsobe PrePared

froY'o^'

l9. lTll (1988).

ror /tYo'-7Cou'

t . i l | - 5 1

w

\ryl l t l

O

O

5

6

alkyl-4-aminoquinolines.2 Thus chlorinationof o-nitrobenzaldoxime (7) followed by reactionwith N(CrH,).andtrappingwith phenylacetylene resultsin the isoxazole CH:NOH

1yxs5 2) ry, C6H!C=CH,

lli'-::1.e.

e,'

"^

.ttt'o

4

6

Ho/

E7

56%

Not CuH,

o-N E

to hydroxamicacid n .,.Jorimes n i:.'up. This reactionhasbeen (1.) B iir.tron of salicylaldoxime a nitrileoxide, pr::.1:regenerates tlr: J The N-O bond can be c.':.r.rtedinto the chalcone4 on ri(.: tr\ classicalmethodsto the r.l'ic.rn be usedto synthesize2-

-uo" jft,l*'ni

CoH,

Et

N-Chlorosuccinimide-Dimethylsulfide

8 in 56voyield. on prolongedcatalytichydrogenation8 can be convertedinto the isoquinoline9 in about 60% yield.The sequencecan be modifiedto providequinazolines. II. Thomsen andK. B. G. Torssell, (1988). ActaChem. Scand,R42,303 ' Idem,ibid.,842,309(1988).

N-Chlorosuccinimide-Dimethyl sulfide(Corey-Kim reagent). Selectiveoxidation of a primary hydroxyl group.t The first synthesisof the secoiridoid4 has been achievedfrom the tetraacetate(1) of secologanin,the biologicalprecursorof secoiridoids.Dihydroxylationof L with oso,, and potassium

Chlorotrimethylsilane. D iastereoselective|,4_addition o! a enone(1) hasbeenresolvedby kinetic rcr by cinchonidine. It undergoes highll.dir the presenceof ClSi(CH.).anOHMp'f ro 95Voyield-l This stereoselective Michael reaction from a cyclohexenone (l).,

ot l I (cH3)3siA/

ll

CHrMgBr, CuBr, s(cH,L,cls(cH!), e4qo

D

(G,}S

(R)- (-)-l

osoa,KCIO3, HO

gD - 9.5o

Dioxme, HrO 45qo

HOH2C

r(R=Ac)

c(cH,),

Oglu(OAc)o 7

rCHr)rSi ,no"lr.rcs.s1cHrl

o

-25 + 0' CH2CI2, J C6H5CH3,

M. Asaoka,K. Shima,andH. Takei,Tetral* V. Asaoka,K. Takenouchi, andH. nf<ei. Cf

i OH

oglu(oR)4 3 ,R = A c 4 ,R = H

chlorate2givesthe bicyclichemiacetal2. oxidation of 2 to the tetraacetate(3) of secogalioside (4) presentsthe problemthat the usualoxidants,PCCor thosederived from DMSO, oxidizethe lactol group of 2 more readilythan the primary hydroxyl group. However,the Corey-Kim reagentprovides3 as the only product,albeit in only moderateyield. Hydrolysisof 3 to the secoiridoid4 is effectedwith K,CO. in methanol(60% yield). ' L. F. Tietze,S. Henke,andC. Bdrtels,Tetrahedron, 44,7145(1988\. ' K. A. Hofmann,Ber.,45,3329(1972\.

Chlorotrimethylsitane-Seleniumdiorilc. ROH --->ft(1.r Chlorotrimethylsilar rlkyl chlorides,but this conversionproccc lctual reagentis believedto be selenium( r:olatedin 74Voyietd from the reaction of !

J G . L e ea n dK . K . K a n g , , /O. r g . , 5 3 . 3 6 !( t

Ctlorotrimethylsilane-Zinc chloride. Intramolecular tundem Michael rea Irnes suchas pentalenene(5) have been str :nrramolecular tandemMichaelreadion as :ncvclicsystem.Lithium amides, evenbully r dimethyl-r-butylsilyl triflate.Annelationt (]Si(CH.)i, zinc chloride, and N(C.H.).at t

Chlolotrimethvlsilane-Zincchloride

)n t ..rn be converted into the I -: :::Lrdifiedto Provide qulnH: : : (1988).

E9

Chlorotrimethylsilane. Diastereoselectivelr4-addition of cupratesto enones. 5-Trimethylcyclohexenone(1.)hasbeenresolvedby kineticresolutionvia the adductwith p-toluenethiol by cinchonidine.It undergoeshighly diastereoselective addition with cupratesin the presenceof ClSi(CH.)rand HMPT to furnishonly the trans-'|.,4-adducts in 8895Voyield.l This stereoselective Michael reactionprovidesa synthesisof ( - )-vetivone(3) (1).2 from a cvclohexenone

I : : . :i a n t ) .

the first synthesis of the ? .,. I r of secologanin,the bir': I .itth OsO. and Potassium C ' )Cl{,

\-

o

t'

CHrMgBr, CuBr, s(cH,\,clsi(cH3),

I

ll

I

r------

(cq)3siA/

e4%

,\ | t

| l

Br(cH,)r u,."r)t=ttc*!)z'znh'(tqa)

2) NaoCHl

(49Eo)

(cH3)3sitrL/.cHr

(R)- (-)-l oo-9.5o

)

I

OSi(CHr)3

tl

c(cH,), OAc).

rCHr)rSi c-- - r'ti,ctr,-:5+o' , )cH.

l

/\ )

I

oR).

i= ::

M. Asaoka, (1987). K. Shima, andH. Takei,Tetahedron Leuers,8,5669 M. Asaoka,K. Takenouchi, andH. Takei,Chem.Leuers,1225(1988). Chlorotrimethylsilane-Seleniumdioxide. ROH --->RCl.t Chlorotrimethylsilaneitself does not convert alcoholsinto rlkyl chlorides,but this conversionproceedsreadilyin the presenceof SeOr.The rctual reagentis believedto be selenium(IV)oxychloride,SeOCL,which can be :olated in74Vo yield from the reactionof SeO:with ClSi(CH.).. J. G. LeeandK. K. Kang,,/. Org.,53,3634 (1988).

(3) of D: : f, tc) the tetraacetate derived those or PCC \.J.rnts. e. r;i: r than the PrimarY hYdroxYl in !r -1 .. Ihe onlY Product, albeit in KrCO3 with effected is { :J n;

,g

- rj 11988).

Chlorotrimethylsilane-Zincchloride. Intramolecular tandem Michael rcaction,t Angular triquinane sesquitersnes suchas pentalenene(5) havebeensynthesized from the bis(enone)L by an .ltramoleculartandem Michael reaction as the key step for conversionto the ::rcvclicsystem.Lithium amides,evenbulky ones,are not usefulfor this step,nor . dimethyl-t-butylsilyl triflate. Annelation can be achievedby reactionof I with t'lSi(CH.)., zinc chloride,and N(C,H.). at 160"in either tolueneor CHrClr. Use

90

Chlorotris(triphenylphosphine)rhodiun

of either solventgivesriseto a mixtureof 2 and 3, but yieldsare higherin toluene. The ketones2 and 3 are convertedin three stepsin about707ooverallyield to the keto esters4 and then into pentalenene5.

Hydroboration of alkenes., Wilkin hydroborationwith catecholborane (CB). and stereochemistryof uncatalyzedhyd OH

CISi(CHe)r,ZnCb

r-IJ

\

ffi;;.

rtctit>''rnr' rob' O ,

J3". CH,

,-1

.)*CH" : ,A\24.

CH, CH,

cH'a-L-2

CH,

4

S

rM. Ihara,M. Katogi,and K. Fukumoto,"/.C.S.Perkin1,2963(1988)

Chlorotris(triphenylphosphine)rhodium(1). Decarbonylation of sugars.l Aldoses undergo decarbonylationwhen treated (NMP) at 130".Thus glucose with this organometallicin N-methylpyrrolidin-2-one (equation I). yield is convertedinto arabinitolin 88Vo

cHo H {o"

T"

HO

(r)

H H

CH"OH

-l-;

HO

I

Ton to"

I,NMP> 88%

I H +oH H

+ ClRh(Co) P(C.H),]'

*o"

cH2oH

cH2oH

A similar reactionwith ketosesis more complex.Thus fructoseis converted into furfuryl alcohol (797o yield).

cH2oH FO

no{n u-fou H-+-OH cH2oH

,.NMp, [oHc-7o;-cH,oH-l -.-4'o ie% \_/ ,t-cH,oH 'x,o \J ) L

OH

,,\

A

\./

\./

c)l ll-l

o" |

a otl

*

9.BBN 86% CB, cat. 84% OH

cr!oH

*,,

t t t ) L _| 9-BBN CB, cat.

83% 934o

I 9

cyclohexenol,the regioselectivityis rcw reactions,but the diastereoselectivitv is r

os

OSi+-BuMe,

ouysr^YzcH' CH, 9-BBN CB, cat.

--+ Bu 94% 80%

the exocycliccycloalkenes(equation It). diastereoselectivity, as does the catal!,zc cohols(equationIII). The catalyzedhydr resultsin the primary alcohol(>99.SVcar Cyclization of 1,6-enynef (cf. Ll. 9l: catalyzedby palladium or nickel complerc products.However, cyclizationcatalfzcd to methylene-2-cyclohexenes. Substitutio pressesthis cyclization,which probablv u bond of the terminal alkyne. Example: C2H5OOCv^\:cH

ar",oo"zV\cH,

ri(rr ot E

Chlorotris(triphenylphosphine)rhodium

[e hrgherin toluene' F orerallYieldto the

Hydroboration of alkenes.2 Wilkinson's catalyst is effective for catalysisof (CB), whichcandifferfrom the regioselectivity hydroborationwith catecholborane and stereochemistryof uncatalyzedhydroborationwith 9-BBN. In the caseof

,\ (Dl n

o

3 (35Vo)

\-/

OH

OH

OH

CH,

91

t

Ao"

ll-l

\,/

_

+ d , o H ^ *^

|

(,

OH

_

_

OH

l

u...,o",rr9o"

E3:2 1 8 I:

9-BBN 86% CB, cat. 84%

r

72:9

OH

cH2oH

}t,

ut,(, 9-BBN CB, cat.

lv\\

1:l 9 :I

83% 93%

cyclohexenol,the regioselectivityis reversedin the catalyzedand noncatalyzed reactions,but the diastereoselectivity is comparable.In the hydroborationswith OSi-t-BuMe,

orr I.rtionwhentreated Thusglucose l, .,r 130o.

.P, CuH5)3lz

u. lructose is converted

701--cHPn

: *_ll

CH,

CHt 947o 80%

osiR3

OSiR"

(rrr) Buv", ---.*r"\lo" 9-BBN CB. cat.

),

...crLoH

+

+ BuYoH : CH3 ll:89 96:4

the exocycliccycloalkenes(equationII), the catalyzedreactionshow high synallylic aldiastereoselectivity, as does the catalyzedreactionof 1,1-disubstituted cohols(equationIII). The catalyzedhydroborationof monosubstitutedl-alkenes resultsin the primary alcohol(>99.5Voat -40'). Cyclization of 1,6-enynef(cf. 13, 91,;14,299). Cyclizationof theseenynes ring catalyzedby palladiumor nickel complexesgenerallyleadsto five-membered products.However, cyclizationcatalyzedby Wilkinson'scatalystgenerallyleads ro methylene-2-cyclohexenes. Substitutionon either of the terminal groupssuppressesthis cyclization,which probablyinvolvesinsertionof Rh(I) in the C-H bondof the terminal alkyne. Example:

c,Hrooc'f\=c" CrHroocl-Aag,

^tlt''rfl*.-.r",:::11 -

13% ar"roo"zVcH"

y2

ChromicaciGChlorotrimethylsihne

satisfactoryyield. Unsymmetricaldisub,stn ketonesin about equal amounts.yields fr only fair. This oxidation is generallyusc suggests that the actualoxidantis a polp

rM. A. Andrewsand S. A. Klaeren,J.C.S.Chem'Comm',1266(1988)' 2 D. A. Evans,G. C. Fu, and A. H. Hoveyda,Am' Soc',110'6917(1988)' I R. Grigg, P. Stevenson,and T. Worakun, Tetrahedron, 44, 4967(1988)'

Chromic acid. in scetone (1, 142). Jones reagent can oxidatively rones reagent (cro!-H,) cleave sec-terr.L,2-glycolsin high yield.t An a-hydroxy ketone may be an intermediate (equation I). Note that an epoxide can also be cleaved to a keto acid.r

O*'?lj'"'"""

CI(},J, H3O'

CrOr, HrO'

50P _-_-,

_€

CH3(CHr)1CH:CHCH:

95%

97

-+

CH.(O

(I) AcO (CuHr)rC:CH,

cHrcooH as* ronoo"ia. J

;-r

(CuHr)rC:O

J. G. Lee andD. S. Ha, Tetrahedron Lcncr.

Chromium carbenereagents. [(D i methy Iami no)mert y k nelcllrc n iu, with diphenylacetylene at g0" in THF to fo (e). This ketene(a) reactswith iminesro f( stereoisomer.

Another example: CH,

(CO)rCr:C-

"CH:CHz I

o CH,

coocH3

6403(1988)' rR. de A. Epifanio,W. Camargo, Letters,29' andA. C. Pinto,Tetrahedron Chrornic acid-Chlorotrimethylsilane. alkenesare oxidized by o.-Chloro ketones. Both cis- and t/4t2s-disubstituted to a-chloro ketones in in CCL dissolved reagents two of these a combination

_N(CH.), -+ C.H,C:CC"I -H

Chrornium carbeneresgents

w. .:.6 (1988). , 1 1 1r1e 1 7( 1 9 8 8 ) . , +{ r$- (1988).

J ,:rr'sreagentcan oxidatively dr.'r', ketonemay be an interr' ^. cleavedto a keto acid.'

o

CrO3, CIS(CH3)3

cct4,25" ----------------+ E3%

CI

H. I l-'t../ D ,)

c

CrOJ, H3O* 5d -____------1 95%

CH3(CILCH:CHCH,

---+

l

o

^_- _l + CH,(CHJ.!HCCI-I, ti CH3(CHJ4CCHCH, l

o

l

l

c

(40Vo)

CH" I

a\v) t t *-o$9

93

satisfactoryyield. unsymmetricaldisubstituted arkenesafford both possiblea_chloro kelon-es in about equalamounts.yierds for oxidation of trisubstitutedalkenesare only fair. This oxidationis generailyuseress in the caseof l-arkenes.The report suggests that the actualoxidantis a polyoxochromium dichloride,Cl(CrOr)"Cl.r

(CoHr)rC:CH,

l CrlCoOH

rs* ronoo"ia. J

r

(40Vo)

(CcHs)zC:O

;-

J. G. LeeandD. S. Ha, Tetrahedron Letters,30, 193(19g9). Chromium carbenereagents. [(Dimethylaminolmethylenelchromium pentacarfunyl(l). r Thiscomplexreacts with diphenylacetyrene at g0" in THF to form rn sirr a comprexedenaminoketene (s)' This ketene(a) reactswith imines to form bicycricractams,usuallyas a singre stereoisomer.

jtF +c6H5c =cc.,,'

(co),Cr-. cH":c(cooR)z 30-80%

Copper(I) chloride. Alkyl carbamates. In the prescnc rn DMF at 25" with alcohols,even rcrti 96Voyield.

)

I I P.Ballesteros, B. W. Roberts,andJ' Wong,J' Org'' 4t' 3603(1983)' (1988)' andP.Dumont'ibid'' 53,4859 2J.-L.De Keyser, c. J. c. De cock,J. H. Poupaert, Copper(Il) . o x i d a t ibromide. onofallylstannanes.|OxidationofthesecompoundswithCuBr,in allylicalcohols,ethers, the presenceofwater, alcohols,or sodiumacetateprovides oracetates'AllylicaminescanbeobtainedbyoxidationinTHFinthepresence of an amine. CH.

r

SnBr.

l

%*,"1Nu

cH,r\-Bu

I

cH,\lBu 73% Nu=OQHs Nu=NH(CHr)zCeH:73%

+

CHt

Bu

83:17 1 4 :8 6

CH'

I T. Takeda,T. Inoue,andT' Fujiwara,Chem'Lefers'985(1988)' bromide-Dimethyl sulfide, CuBr'S(CH')z' Copper(I) 'inz;-l,uylotron with a variety of R.rz,i or RZnCl.t cinnamyl chloride reacts Vo) at20" to (5 mole of organozincreagentsin the p,es"nce of this Cu(I) reagent is comparableto that of give the Sp2'-productsof allyiation' The regioselectivity RCu-BF, at -70'.

ROH + C64CH(R)NCO(R=H,CH!)

\t. E. DugganandJ. S. Imagire..S-rnrAc

Copper(Il) nitrate-Montmorillonirc (Cli Nitration and ofidation.t Clar,_su .. :helf-stablefor months.Like clayfen. ;.eavethioacetalsor selenoacetals to tlx -: effectsaromatizationof 1,4-dihydrop :i aceticanhydride,it can effectnitratioa ..,.:'a-preference, which can be enhance ? LaszloandA. Corn€lis, Aldrichimica Aa

(1per(I) thiocyanate,CuSCN. .4renethiocyanation.t Thiocyanano r,.. resultsin both arenethiocyanates an ]l< reactioncan be effectedwith CuSCI rr.moarenesreact with this supponedn r .re the correspondingthiocyanatesin

Copper(I) thiocysnate

lr rr.cnzation of the Products' ilre. ,r KnoevenagelcondenD:he presenceof anthracene' (1)' - Thc [.1+2lcYcloadduct meththe give to der reaction

101

9H, c6H5

=

cl + cHrZnct -Cu(I) Ni(ID

+ cuHrA.zcH2cH3

au"r&cH,

67Vo 65Va

92:8 8:92

Allylation catalyzedby NiCl, complexedwith a phosphineinvolvesan S*2 reactionwith equallyhigh selectivity. E

Letters,29, 5155(1988). Tetrahedron K. SekiyaandE. Nakam,tra,

r:'

R :'o-25o"'

CH":C(COOR)z

rl-t04

Copper(I)chloride. react Alkyl carbamates. In the presenceof CuCl (1 equiv.) alkyl isocyanates in 45rn DMF at 25" with alcohols,even tertiary ones,to form alkyl carbamates 96Voyield.

, CuCl,DMF

.n,,i (1983). (1988)' P Dumont,ibid',5t,4859

ROH + C6H5CH(R)NCO # (R=H,CHr)

?

C6H5CH(R)NHiOR

l31 (1989). \1. E. Duggan andJ. S. Imagire.Synthesis, in he:c comPoundswith CuBrt ethers' alcohols' prrt'rr,Jesallylic rtirlr,rnin THF in the Presence

N,r

,

-

CHr-;\r,Bt

I

CH, : r b

. -.< r1988).

flr a variety rrr. chloride reacts with at20' to Vo) nt I r reagent (5 mole that of to le;irrtrr-is comParable

Copper(Il) nitrate-Montmorillonite(Claycop),12, 231. Cu(NO3),,unlikeclayfen(n, nI), N itration and oxidation.t Clay-supported .. shelf-stable for months.Like clayfen,it is a convenientsourceof NO2* and can to the carbonylcompoundat 25" in high yield. :,eavethioacetalsor selenoacetals in 80-92Voyield. In the presence It effectsaromatizationof 1,4-dihydropyridines .f aceticanhydride,it can effectnitrationevenof halobenzenes at 25"with marked which can be enhancedby use of lower temperatures. :.rrc-preference, Aldrichimica Acta,2l,97 (1988). P LaszloandA. Corn€lis,

Copper(I)thiocyanate,CuSCN. Arene thiocyanation,t Thiocyanationof areneswith metal thiocyanatesusuand the more stableareneisothiocyanates, r.l1 resultsin both arenethiocyanates lhe reactioncan be effectedwith CuSCNsupportedon charcoal.Thus iodo- and -romoarenesreact with this supportedreagent(excess)in t-butylbenzene at 150o '". sive the correspondingthiocyanatesin70-807o yield.

lfiz

Cyanotrimethylsilane

'J. H. Clark, C. W. Jones,C. V. A. Duke, and J. M. Miller' l.C.S. Chem.Comm.,81

(le8e).

uf,ruCN

I

cyano(methylthio)methyltrimethylsilane, (cH.).sicHSCH, (1). The reagent is CH3SCH,CN,with trimethylsilyl availableby reactionof methylthioacetonitrile, yield). triflate and N(CrHs).in ether at 0-5" (80-85% a-cyano vinyl sulfides.r The lithium anion of L undergoesa Petersonreaction with aldehydesor ketonesto give thesecyanosubstitutedsulfidesasElZ mixtures in 60-95Voyield.

, *

ton')c-e CH,/

-$' c1"'14!1,-SCH3+ (cH,),SioLi 6t% CHr'

EIZ=5:1

CH" ',Fe(CO.)" ; ( _ tcg6s ll I I I @_9A

Y.", I

'o"(

Asymmelri c hydrocyanadn reactionof aliphaticor aromatr ticallyactivereagent(l) derivedt poxytitanium(IV).The actualch

rD. I. HanandD. Y. Oh,Syn'Comm.'lE' 2111(1988). CuHra_CuH, 2-Cyanopyridiniumchlorochromate(l), L3' 87. s-Chloro ketones. This chlorochromate(5-11 equiv.) convertsalkenesto c-chloroketonesin 40-95Voyield. The workup is facilitatedby use of Celite as adsorbent.In rare casesallylicoxidationcompeteswith oxychlorination,and epoxides are occasionallyformed as by-products.'

C.Hr- ,O-lOfr > ( l

cH,1J.. ..-oH +rio/c c6H5. c6Hj I, ao + g3o

o c l PrCH:CHn lW

i l l

PrC-CHPr

formed from 1 and TiCl,(O_i-pr) rexcess)and an equivalentof2 ar optically active cyanohydrins.

,/f--/cl -------| { I s'tc. \Ao (exo)

R(AI)CHO + CiS

IA. F. Guerrero,H. Kim, andM. F. Schlecht, (1988)' Letters,29,6707 Tetrahedron cyanotrimethylsilane,(cH3)3sicN.This silaneis presentin solutionin part as the isocyanideisomer, (CH3)3SiNC.'And indeed it is more useful than NaCN for cyanationof the iron complex12to provide2 and 3, intermediatesin a projected synthesisof tridachione.

Asymmenic Strecker amino sl iatalyzedby ZnCl, to opticallyacrr 3-o-galactopyranosylamine as the ( r-aminonitriles,dependingon the iiereomers,whereasCHCI, favon ,

Cyanotrimethylsilane rltr

M \ l r l l c r .J C - S 'C h e m 'C o m m ' ' 8 7

cH3o\^
a-a \"i\tocu,

5 ( 7 :1 ) F..

CH,

cH,AcHo * 8""o"",H9-

CH3OCHTQ

9H'

"",#(t"' o H o = 7l:29) (antilsYn

(1988)' andM. Utaka,Chem.Letters,2003 S.Tsuboi,S. Takatsuka, 'S. E. Drewes, andG. H. P.Roos,Syn.Comm.'fE' 1065(1988). T. Manickum, (DBU, 1). I,E-Diazabicyclo[5.4.01-7-undecene $-and S-Akylation. This basefacilitatesesterificationof carboxylicacids' acids.2 and S-alkylationof p-toluenesulfinic 10,!)

110

l-N,N-Dibenzyl-c-amino rldehydes

p-CH3C5H4SO2H + RX + DBU

#

p-CEC6H4SO2R

I D. Mal, Syn.Comm.,f6, 331(1986). 2G. Biswas (S),308(1988). andD. Mal,l. Chem.Research (N3),Ti(O-iPr), (1), 13,2I7. Preparation.rThereDiazidodiisopropoxytitanium, agentcan also be preparedin situfrom Ti(O-r-Pr)oand 2 equiv. of (CHr)rSiN,in refluxingbenzene. a-Amino acids.2 Treatment of 2,3-epoxyalcoholswith 1 affords 3-azido1',2diols, which can be convertedto amino acidsby RuOooxidationto c-azido carboxylic acidsfollowed by catalytichydrogenation.

o cJr,&oH

OH I

-L-'.tt'yA,,oH

RuCl3

-g{9Lc#,

cooH ,

N3

N3 ( 1 0 0 :l )

R'M, t4\ L-l (R= C4) cHr'

2 CHTMgI cH3Li cH3Tict3 (CHr)rCuLi

n% 9t% t2% W*

""':"(ott

t2* ocH3 /oc6Hs .TiO. 25* C[:C_'os(cH3)3

^uJila,.* cJ,ycooH NH2.HCl

' R. Choukroun (1980). l.C.S.Dahon,1800 andD. Gervais, 2M. Caron,P.R. Carlier,andK. B. Sharpless, (1988). J. Org.,53,5185 Preparation.' Di(benzene)chromium(0). Dehydrogenation catalysts.2 Reduction of di(benzene)chromiumwith potasto 1,4-cyclohexadiene sium sandin DME generatesa speciesthat dehydrogenates probenzene.The catalyst prepared from benzene(1,3-cyclohexadiene)iron(0) and disproportionationto cyclohexeneand benzene. motesdehydrogenation

(CuFIu)rCr. O

p-Amino alcohols.t Alkyllirhium i p-aminoalcohols(2 and 3), with the latu CH3TiCl3,SnCl, can favor the chelatro

25o K'DME ' O

I M. T. Reetz,M. W. Drewes, andA. Sctri

Dibenzyl azodicarboxylate(1). 2-Amino glycosides.t Furanoid or ; this azodicarboxylate undergoa [4+21c1 (3) in 70-80% yield. The adductson trct inversionat Cr to give hydrazines(l). r hydrogenolysis and deprotection. R3Sio-\./o)

,, ^"

\--t/a

&sio-{\\

R3SiO'

RlSiO

t

'E. O. Fischer, Inorg.Syn.,6,132(1960). ' G. Fochi,Organometallics, 7, 2255(1988). N_NHCOOBd

r,-N,N-Dibenzyl-cr-aminoaldehydes,(1). Preparation: RCHCOOH

I

NH2

"*"

COOBzI 4

l) LiAlH.

RCHCOOBzI NBzl,

2)(coclL/DMso, ) RCHCHO

I

NBzlt L-l

Actually, the adductsare cleavedbv includingvariouscarbohydratealcohols. polysaccharides.

Dibenzyl ezodicrrboxylete

* :-CH.CoHrSOzR

p-Amino alcohols.t Alkyllithium and Grignardreagentsadd to 1 to provide B-aminoalcohols(2 and 3), with the latter predominating.Addition of Lewisacids, product2' CH3TiCl.,SnCL, can favor the chelation-controlled

t\.

BzlN,

. 1 3 .l l 7 . P r e P a r a t i o n . ' T hr e ). ;nJ I equiv. of (CH,):SiN,in

t -cr

c6H5.,, cooH I N3

I u". Parc teu" ntr I Y

c6H5

_

cooH

I

NH2'HCl !"* , ' s - l 5 1 8 5( 1 9 8 8 ) .

,OH

L-1(R=CHr)g

*

cHr">1R'

BzlzNa__-OH 'R' ""r"

2

3

87% 9l7o 82Vo 80Vo

5:95 9:91 94:6 25:75

cu':6(oli-ocH3 827o

5:95

CH'MgI CH3Li CH3TiCl3 (CHr)rCuLi

oh,.l. nith l, affords3-azido1,2Ru(), oxidationto c-azido car-

H +5

111

/oc6H5 CH':C-- 'os(cH3)3'TiClo2l7o

95:5

lM. T. Reetz,M. W. Drewes, Angew.Chem.Int. Ed '26' 1141(1987). andA. Schmitz, Dibenzyl azodicarboxylate(1). 2-Amino glycosides.tFuranoidor pyranoidglycals(2) when irradiatedwith undergoa [4+2]cycloadditionto form a dihydrooxadiazine this azodicarboxylate (3) in 70-80Voyield. The adductson treatmentwith methanol(TsOH) open with inversionat C, to give hydrazines(4), which furnish 2-aminoglycosides(5) on and deprotection. hydrogenolysis

with Potas' hrr**nzene)chromium to dr\rrenates1,4-cYclohexadiene I i .:-lclohexadiene)iron(0)proo :rclohexeneand benzene.

, z-'\

:-+

R3sio1.,o),.^",R3sio 1o'rzo\--oBzl _ruL \--ll ;;

88%

.H*_,(' i

R3SiO

R3Sio

cooBzl

2 ,

ll

3

\-/ n

R3sio1,,-1..'ocH,

,-1 'N-NHCooB'l

\

R'sio

/

llli;$.-*n'-soA(o;."ocHr Bq.

L---{

." |.--'NH'

Ho

COOBzI 4

' ^ H

I

:

5

-'.rlr/DMSO

) ) K CHCHO

I

NBzlt L-l

Actually, the adductsare cleavedby various primary or secondaryalcohols, includingvariouscarbohydratealcohols,and thus can be used to obtain aminopolysaccharides.

Itz

1.3-Dibromo-3,5-dimethylhydantoin

lithium-halogenexchangeprovidesl with electrophiles.

I W. Chen,E. K. Stephenson, andM. p r

o phosphorofluoridate, Dibenzyt (Bzlo),$a Or, b.p.-150./0.2mm.

o ll (Bzto),i-oH+ ll,4, I \ttA.

rro- *,,'iF,,, r eoqo

CH,

o -';:L ' [,u,,",,[], Phosphorylation.t Dibenzyl phosphorochloridate is widely used for phosphorylationof alcohols,but is more difficultto preparethan the fluoridate.phenol is very readily phosphorylatedby 1 and csF in cHrcN, and indeed a phenolic hydroxylgroup is selectivelyattackedevenin the presenceof a primary hydroxyl group. Primary and anomericalcoholsare preferentiallyphosphorylatedin the presenceof a secondaryhydroxylgroup.Alcoholsthat are insolublein acetonitrile can be phosphorylatedby L and DBU in placeof CsF. 'Y. Watanabe, N. Hyodo,andS. Ozaki,Tetrahedron (l9gg). Letters,29,5763 1.,3-Dibromo-3,5-dimethylhydantoin (l), 12, 158-159.Supplier:Aldrich. Regioselectivebromination t This reagent.is superiorto NBS for bromination of pyrrole to provide 2-bromopyrrole.After conversionto the N-boc derivative,

'""1"':l-#'--?" ?.1 AIBN.

(cH.).cocolo

Boc

I t) nuli 70% | 2) cts(cH3b THF, -?8 + 0o J

l-\

\^sr1cH,y, I Boc

3,5-Di-/-butyl-I.,2-benzoquinonc,3. l RTCHNHT-->RzC:O,t Alrhorl 1969,it has not been used widet;-.A from both acyclicand cyclicamines. 2-amino-4,6-di-r-butylphenol, can bc chemicalor dichromateoxidationrn 5 I R. F. X. Ktein,L. M. Bargas, andV Hr

Dibutylboryl trifl uoromethanesrfiof Boron enolates of thioglycobtaof the low acidity of the c-protons.Hr a boron enolateon treatmentwith Ho enolateundergoesaldol reactionsrrd ity.' $C"H. _ LbGe | CH3CHO+ CHTCOOCH,j%5

G

't

' Y. SuganoandS. Naruto, Chem.plurm.

Di-t-butyl dicarbonate(r-Boc,O). NHCbo --> NHBoc. This inrercq hydrogenationcatalyzedby pd_C in O can also be effectedby reactionwith 1 ethylaminein the presenceof excessr-l ' M. Sakaitani, K. Hori, andy. Ohfunc.Ia

2,6-Di-r-butyl-4-methylphenol. Conjugate addition to a,p-ur.rrcl are too hinderedto form esterenolat6. I conJugate additionof organolithiumrea .l-methoxyphenols, which are easill.clc observationthat BHT estersare redls

2,6.Di-r-butyl-4-methylphenol

113

lithium-halogenexchangeprovidesN-boc-2-lithiopyrrole for subsequentreaction with electrophiles. rW. Chen,E. K. Stephenson, andM. P.Cava,Org.Syn.,submitted (1989). 3r5-Di-t-butyl-1r2-benzoquinone, 3, 78-79. pr(--Q.r Although this conversionwas originallyreportedin RTCHNHT-.-> 1969,it has not been usedwidely. A recentoverviewreports yields of 83-937o from both acyclicand cyclicamines.A further advantageis that the by-product, 2-amino-4,6-di-t-butylphenol, can be convertedto the benzoquinoneby electrochemicalor dichromateoxidationin 55-65Voyield.

5 i , ' t J . 2m m .

' ' ) l

rR. F. X. Klein,L. M. Bargas, (1988). andV. Horak,J. Org.,53,5994

fu:: rr widely used for phosarc :hanthe fluoridate.Phenol 1l ( \. and indeeda phenolic rr..cnceof a primaryhydroxyl in the Rn::rll\ phosphorylated ha: ,rc' insolublein acetonitrile l:F

Dibutylboryl trifl uoromethanesulfonate(1). Boron enolatesof thioglycolates. Estersdo not form boron enolatesbecause of the low acidityof the a-protons.However,methyl phenylthioacetate (2) forms a boron enolateon treatmentwith Hunig's baseand dibutylboryltriflate, and this enolateundergoesaldol reactionswith aldehydeswith high syn-diastereoselectivity.'

fcuH' r

,,l:.'l;;.

CH3CHO+ CHTCOOCH,s5-+ 'oo

,

lcoH,

CH''Y -J- -cooan' OH

^1. 96:4

s t . . 2 9 . 5 7 6(31 9 8 8 ) . 5" :upplier:Aldrich. tra-:r,)rto NBSfor bromination rr.:,:r to the N-bocderivative,

-ll

t-----:\

\\

\/-t.

t) nul-i '0,+I zy | cts1cH35 -?8+0' JrHF,

si(cH3)3 Boc

| OH

I Y. Sugano andS. Naruto,Chem.Pharm.Bull.,%,4619(1988). Di-r-butyldicarbonate(t-Boc,O). NHCho --->NHBoc. This interconversioncan be effected in high yield by hydrogenationcatalyzedby Pd-C in CH.OH in the presenceof excesst-BocrO.It can also be effectedby reactionwith (CrH.).SiHcatalyzedby Pd(OAc), and triethylaminein the presenceof excesst-BocrOin C'H.OH. rM. Sakaitani, (1988). K. Hori,andY. Ohfune,Tetahedron Letters,29,2983

Boc

I

lCuH' a"'a4coocH3

2,6-Di-r-butyl-4-methylphenol. Conjugate addition to ar$-unsaturated esten. Fsters (BHT) of this phenol are too hinderedto form esterenolates,'but ct,B-unsaturated BHT estersdo undergo conjugateadditionof organolithiumreagents,2 asdo esters(BHA) of 2,6-di-r-butyl4-methoxyphenols, which are easilycleavedby CAN oxidation (13, 94-95). The observationthat BHT estersare reducedby sodium in liquid NH. to the corre-

tt4

2,2-Dibutyl-2-stanna-1,3-dithicne

cH"

t -

+ CH:CCOOBHT -

cHrI

Na.NH3 ._

90%

45%

t

LiF

aldehydereactsmore readily than an er reversedin the caseof an aromatic d& betweena straight-chainaldehydeand a I

I

BucHo*n-c,n,,c{]**

tt'-O

a-

'jf"n,o"

Cor(CO)r 5tEo

CH,

c,oH7cHo.*"{]

c=cH

, cJ

6 (cis/trans = R R .1 ' \

4

BUCHO + (CH,)TCCHO -+

BoO \

CH,

7

spondingalcohol providesa synthesisof angularlyfused triquinanepentalenene (7). Thus conjugateadditionof L to 2 followedby in situ methylationfurnishes3, which is reductivelycleavedto the alcohol4. This is convertedby known reactions to the enyne5, which undergoescyclizationwhen heatedwith Cor(CO)" (t2, 1,64) to a mixtureof two triquinanes6, in qhich the productwith the desiredconfiguration at Cr and Copredominates. Remainingstepsto the pentalene7 areknownreactions. rR. Hiner,T. Laube,andD. Seebach, Am. Soc.,f07,5396(1985). 2N. E. Schore andE. G. Rowley,ibid.,ll0, 5224(1988).

rurr6t I 2,2-Dibttyl-2-stanna-1,3-dithiane, '5J

' M. Wieber and M. Schmidt,I. Organoma.C : T. Sato,E. Yoshida, T. Kobayashi,J. Orcn. r ( 1988). 'M. Schmeisser, P. Sartori,and B. Lippsrnckr

3,4-Di-r-butylthiophene l,l-dioxide (l). Preparation:

o\ (c\\c'/

lo Tftt:". tcH,;{ fc(cn"i"

(1).

The reagentis prepared'in about 50Voyield by reactionof propane-l,3-dithiol with Bu,SnCl,and N(CrH,)3. Reaction with RCHO and acetals.2 In the presenceof dibutyltin bis(trifluoromethanesulfonate), 2,3this reagentconvertsaldehydesor their dialkyl acetals or ethyleneacetalsinto 2-alkyl-1,3-dithianes (70-85Voyield).However,the reagent differentiates betweenaldehydesand acetalsasshownin the examples.An aliphatic

1r2-Di-r.butylbenzenes.r This reagenrr phenylvinyl sulfoxide,an acetyleneequivalc acid to give o-di-r-butylbenzene in Tl% *l

3,4-Di-t-butylthiophenel'l.dioxide

Na./t',1H3 --------------)

\-

45qo

115

aldehydereactsmore readily than an ethyleneacetal,whereasthe selectivityis reversedin the caseof an aromatic aldehyde.The reagentcan also distinguish aldehyde. betweena straight-chainaldehydeand a branched-chain

-( IOBHT

BuCHO+ , "r",r"{]

g

/SI

BuCrH

s-/

/S

+

)

n-C,H,rC{{

s 93:7

\+

".",{] - ",rr,iD c,oH?cHo.

. ".r,"i]

6 (cisltrans = 8 8 :1 2 )

3:97

BuCHO + (CHr)TCCHO+

,sl

BuCrH

s-/

)

+

/s

(CHICC\H

s 80:20

I M. WieberandM. Schmidt, Chem.,1,336(1964). J. Organomet. r T. Sato,E. Yoshida, Leuers,29'3971 J. Otera,andH. Nozaki,Tetrahedron T. Kobayashi, ( l e88). 'M. Schmeisser, (1970). andB. Lippsmeier,Ber.,103,868 P.Sartori, fu.rJ triquinanepentalenene i;::, methylationfurnishes3, r.1\.rtcd by knownreactions a:c.j rrith Co:(CO)'(n,rc4) e::h thedesiredconfiguration lt;.c1c7 areknownreactions. lr

-,.5).

1,l-dioxide (1). 3,4-Di-t-butylthiophene Preparation:

o\

rict4.z^tcH,l,c[Pc(cH,), lo r (CH")^C1 \c(cH")" -M ' i \ s3% \r/ \r/

1vr.ox 2)crcrH'colH '

(CH3LC\

/C(CH3)3

lt \ \s/ r:.trLrnof propane-1,3-dithiol rc..rce of dibutYltinbis(trilehrJcsor theirdialkYlacetals i ,,rc.J). However,the reagent An aliPhatic r r1 :hc examples.

o2 I This reagentundergoesa Diels-Alder reactionwith 1r2-Di-r-butylbenzenes.r phenylvinyl sulfoxide,an acetyleneequivalent(8, 399),with lossof benzenesulfenic in77Vo yield. acid to give o-di-t-butylbenzene

116

Dibuivltin oxide

I S. J. Danishefsky, R.

o-t'tfo""',1t"')'tfi I + cuHrSocH:a",

Hungate, andG. Sdrs

+ sor+ c6H5soH (cH^)"cN

Dicarbonyl(cyclopentadienyl) t (dinrcthybr Cp(CO),FeCH,S(CH3),BR-(t), air-stab

2 (77Vo)

Diels-Alder reactionsof I with a varietyof alkynesprovidesa route to various substitutedo-di-r-butylbenzenes. ,,':'"';'Jl:< I M. N. Mattson,E. J. O'Connor,andP.Helquist,Org. Syn.,submitted (1989).

sas;l | |

,\

,-=1

''\^ ,1

)

Bu/

|

|"^"'il'"'', I

-o I n l

-rul

71%

*'"'

Di-p-carbonylhexacarbonyldicobalt'Coz(CO)r. Thesecomplexes(11, 162Alkyne-Co{C O) 6complexes,(RHR)Co2(CO).'' 163;12, 163-165;14, 1I7) can be preparedin situ and usedfor synthesisof cyclopentenonesin moderateyield.

CoBrr+ Zn+ COB ) :L-H st\

( -\ oll lt

..IIi% fCor*oH I ll

ooq,ru,s,1c',;, cHcr3 fr>

t t l c6H5sicl'osi(cH3)3 L

fs'

9H'

t'"'Y}t"ll c^H.si

,

J

I

- -cHrr :)6w

cuHt-"A.cH, : c6H5si

ll o

CH,/\CH, (antilsyn>20: 1)

]lfil.l

cuH'-*\.cH' i

t

l

o H o

l

tA

Dichlorotris(triphenylphocphinc)ruthenium

' E. Hengge,G. Bauer,E. Brandstatter,andG. Kollmann,Monatsh.Chem.,lM,887 (1975). 2T. Hayashi,Y. Matsumoto,and Y. Ito, TetrahedronLetters,29,a147(1988);idem., Am. ,Soc.,110,5579(1988).

(1). Dichlorotris(triphenylphosphine)ruthenium Intramolecular Kharaschr-type cyclizations.z Unsaturated c,a-dichloro esters or carboxylic acids undergo cyclization in the presence of various transition metal catalysts,particularly Cl,RuIP(C6Hr)r], or ClFeIP(OCrHs)3]3.3Thus ethyl 2,2dichloro-6-heptenoate (2) in the presence of 1 cyclizes rapidly to the cis-1,2-disub-

cl 0)\

,-f,cooc,n, ul Ka",

r, 1550 ----+ 60-7W

/\t.coocrHs ,/ I

\

|

H c4cl

.ff-""]

9,l0-Dicyanoanthracene (DCA). Triplex catalysis.t 1,3-Cyctohc der usualconditionsalthoughit is kr ence of a sensitizer.Actually. 1.3-c with a silylenote [4+2]cycloaddition ene (1). Similar resultsobtain *rrh r 2\ I \-/

Ear cd':l rt

crr l + c H '" : C / u t -osi1cH,;,

2 7 hrs. 3(cisltrans= lil) " =1:4) 16hrs. (

2ra

(3-5Va)

*,d:lo"';i;,W".ff-l

cycloadditionsinvolve a complex(tnp and the dienophile.When 1,4-dio.an reactionwith 1, the ratio of + 2laddl [4 essentiallyonly [2+2]adductsform lt

4

5

Pho tocycliza ti on of enoncssrlrria (>320 nm) of thesesubstrateswirh D(

(4Vo)

The corresponding stitutedcyclopentane, andepimerizesslowlyto the trans-isomer. (5) In both (4) the same conditions. under acid cyclizesto the crs-bicycliclactone casesonly a trace of cyclohexylproductsare formed. This radicalcyclizationcan providebridgedand fusedcyclicsystems. Example:

O

A I \.,\-

O

cooc2H5

A I

\1

(cHJ3SiCHr\/

an \)ct-f-c,

,rv,DcA ctt:9-{(n"

ll

7

8

I

r,rss'

Bzl

cooc2H5 (r2%)

' C. Wallingand E. S. Huyser, Org. React.,13, 91 (1963). 2T. K. Hayes,R. Villani, and S. M. Weinreb,Am. Soc.,U0, 5533(1988). 3 S. D. Inel, A. D. English,C. A. Tolman, and J. P. Jesson,Inorg. Chim. Acta,33, 101 (1979).

A

V

| \-*',


320 nm) of thesesubstrateswith DCA as sensitizerresultsin N-heterocvcres.

tt9o) The corresponding thc :'.rru-isomer. u:rJer the sameconditions.In both brned. I .:rJ fusedcyclicsystems.

o

o

tl

I

,rrv, DC

ll

t"'o" ii",

\-,,1r

,.\

t

l

78%

(cH3)3sicHr\,,

|

\*/ Bzl

I

Bzl

) -coocrHs

3 (exolendo = t : l)

cycloadditionsinvorvea comprex(triprex)composed of the sensitizer,the diene, and the dienophile.when 1,4-dicyanonaphthalene is usedas the sensitizerin the reactionwith 1, the ratio of [4+2]adductsdecreases relativetothe[2+Z]adducts; essentiallyonly [2+2]adductsform when benzophenone is the sensitizer.

-'l

l,'Y"' -cooHl I

+|

ng

9,lO-Dicyanoanthracene (DCA). Tripl* catalysis.t 1,3-Cyclohexadiene does not undergocycloadditionsunder usual conditionsalthoughit is known to dimerizeon irradiationin the pres_ ence of a sensitizer.Actually, 1,3_cyclohexadiene can undergoboth [2+2]_ and [4+2]cycloadditionwith a silyl enol ether suchas 1-trimethyrsiloxy-1-phenylethylene (1). similar resultsobtain with trimethylsilyrketene acetar.These sensitized

+

o tl

A

(129o) (l+:,

-\.. ll0. s533(1988). . P ri\son,Inorg.Chim.Acta,33,101

I

V

-+

ll

| \-*r.

/-Si(CH3)3 'CH,, (7 l%o)

13{f

DicYdobexYlbonne

rN.AkbulutandG.B.Schuster,TetrahedronLetters,2g'5125(1988)' 2W. Xu, Y. T' Jeon, E. Hasegawa,U. C. Yoon, and P. E. Mariano' Am. 5oc.,111' 406

(1e8e). (DCB)' Dicyanobenzene Photosensitizedcyclobutanation.|Conjugateddienesandenamidesundergo photosensitizedcrossadditiontoprovidecycloadducts,whichcanbehydrolyzed tovinylcyclobutylamines.TheseSecondafyaminesundergoabase-catalyzedrear,ung",n"n.togivecyclohexenescorrespondingtotheDiels-Alderadductsofthe diene and the enamide'

Dicyclohexylcarbodiimide-Dimethyb Macrolactonization. This versro specificallyfor lactonizationof I to (.

:,EC : H ' C

HO HOOC

I

('n

,rrl (E,E)

ftv.DCB

firtt ll

cHrcN

+ HCa ZCH'-? N I

t"r-..,-., ln'

H L kNCocH3 'H tl

CHr/

cHft

( 3 . 5 l: )

'G. E. Keck.E. P.Boden.andM. R l*r

Di(cyclooctadiene)nickel(0), Ni(COD 14+4lCycloadditions. This rerr a cyclooctane-containing terpenoidl5 tainedby reductionof the t-alkvl alk_

t-tto' --0"" | ros. *n*n, Hoctl,ctl?oH I KH, THF A

NHCH3

CH, (endo)

er%

gH,> H I 1i

o CH,

kNHCH3 -H

CH:CH,

l)L^Dt+ L 2) Rcd-L Cl

CH,

CHr/

CHt

(3.2:1)

rN.L.Bauld,B.Harirchian,D.W.Reynolds,andJ.c'white,Am'soc''110'8111(1988)'

DicyclohexYlborane. R c H 2 c N . T h e s e p r i m a r y n i t r i l e s c a n b e o b t a i n e d i n 7 } _ g S v o y i e l dofb y h y followedby addition droborationof a terminal alkenewith dicyclohexylborane amount of Cu(acac),,which is an excessof CuCN and Cu(oAc), and a catalytic yield. The overall processeffects not essentialbut which markedlyimprovesthe anti-Markownikoffhydrocyanationof l-alkenes"

*"1""t, Iffi*5 tRrR'cH-cHrr*r, RrR2c:cH2 R'R'CHCH2CN

rY.Masuda,M.Hoshi,andA'Arase,t'C'S'Chem'Comm''266(1989)'

\H, |,'[?i*,cx ,fH' CH,

6?q

cH

Di(cyclooc,ladiene)nickel(0)

:::i {1988). E \t.rriano,Am. \oc.,111, 406

Dicyclohexylcarbodiimide-Dimethylaminopyridine(13, 107-108). Macrolactonization. This version of Steglich esterification was developed specificallyfor lactonizationof I to ( + )-colletodiol2.

CHr

drcnesand enamidesundergo rtr. *hich can be hYdrolYzed rearmJcrso a base-catalyzed of the adducts r Drels-Alder

HO HOOC

'cH,

I

I

I -\COCH3 .H

- lKoH,l-llo" ' . -' tt,*tl' HocrlcqoH J

(+)-2

' G. E. Keck,E. P.Boden,andM. R. Wiley,,/. Org.,54,896(1939). Di(cyclooctadiene)nickel(0), Ni(COD),. This reactionprovidesan enantioselective [4+4lCycloadditions, synthesisof a cyclooctane-containing terpenoid(5). The opticallyactiveprecursor(3) was obtainedby reductionof the r-alkylalkynyl ketone I with lithium aluminumhydride Sn(CHr),

!1,-.-

CH:CHz

,, I .NHCH" ..-_____r{ 'H

l) LiAtH4,D@on atc.(97%) ^tr 2) Red-Al.ClSn(CHrh(839o) Ln?

CHt

9H,

1."

CH, l2:1)

l\ l:::. .'lm.Soc.,110,8111(1988)'

-W*"",

CH, Fr:c,l in 70-98Vo Yield bY hYItlr.rne followed by addition of ;irrrullt of Cu(acac)2' which is ciJ fhe overall Process effects

67%

CH,

C4

CuCN'0+20"

,*, :gH#%

CH, CH,

R'R,CHCH2CN

CH, or,': . 3fr6(1989)

o

: l l l) Dcc,DMA',DMAp.Hcl oAA4o 2)H',cH,oH , i I 62qo g4€"'/l\/".cu, : O H HO

H3

QH,

(l1

132

Diethylaminomalonate

modifiedby Darvon alcohol in >98Voee. The alcoholwas convertedto the bisintramolecularcyclizationto 4 in 67Vo diene 3, which undergoesnickel-catalyzed yield. Remainingstepsto 5 includeconjugatereduction(copperhydride), hydroboration,and oxidation.

CH.

lP. A. Wender, (1988). Am. Soc.,110,5904 N. C. Ihle,andC. R. D. Correia,

C^l Dicyclopentadienylyttriumchloride, CprYCl. Preparation.I Fulvenes.2CprYCl reactswith aldehydesor ketonesin DME at 80'to form fulvenesin 60-95Voyield. S. Husinec, V. Savic,andA. E I

o ll

CprYCl C2H5CCH3+ ;;-

a

.cH.,

(r-.lar",

Diethyl oxalate,(CTH,OOC):I

rR. E. Maginn,S. Manastyrskyj, Am. Soc,85,672(1968). andM. Dubeck, ' C. QianandA. Qiu, Tetrahedron (1988). Letters,29,6931

Dicyclopentylboryl trifluoromethanesulfonate'(c-CsHe)rBOTf(1). t:ans-Glycidicesters. The Darzenscondensation'usuallyprovidesa mixture are obtainedby condensationof of trans-and crs-products.Only the trdr?s-esters with aromaticaldethe dicyclopentylborylenolateof cr-bromo-/-butylthioacetate hvdes.2

Ethyl 2-oxo-3-alkcnoaus, I reactwith diethyl oxalatein TtIl estergroup of diethyl oxalateto

CH'CH:CHMgBr M. Rambaud, M. Bakasse, G.

O

ll ArcHo+ BrcHrisc(cH,), #F

-Q[ nrMsc(cH3)3

I M. Ballester, 283(1955). Chem.Revs.,55, 2R. P. Polniaszek (1'989). andS. E. Belmont,Syn.Comm.,19,221

$( Diethylphosphono)-2-bcrcrd Preparation:

(CrH,O)P(O)CHTCH : CHCHTOI

Diethyl aminomalonate. I3+2lCycloaddition to pynolid.ines. The reaction of diethyl aminomalonate with formaldehydecan generatean azomethineylid (a .- |

ovqall

| -

..^.._ o ll Te#' ----rn_cuH,rCHrC(cH2)20H

)

12%.. overarr

|

5

rc .:mrteduse becauseof thermal ll;:r.'n of Cl:CHLi with Ti(O-i-Pr). t ' u hich is stableat 0o.Moreover nrri:rable group selectivityfor allll

-

4

R 3

K. Tamao, K. Maeda, T. Tanaka, andy. Ito, Tetrahedron Leuers,29.6955 (lgllti). 2,2'-Dihydroxy-l,1,.binaphthyl(1). Resolution of surfoximinesJ Alkyr aryl sulfoximines(2) canbe resorvedby complexformationwith (+)_ or (_)_1 (equation I).

(I)

o tl ArS-R tl

cllta.2s" + (+)-l -F=ff-

NH

(+)-2,Ar = n-CH,CuHo, R=CH:

G)-2+ (+)-r-\+)-2 (9O9oee)

l: I

_^_ | t) cryshllizdion

/w'J2'' NeoH

(R>(-)-2(r00voee)

136

2,2'-Dihydroxy'3,3''bis(triphenylsilyl)1'l'binaphthyl-Trimethylaluminum

The efficiencyof the resolutionis dependenton the Ar and R groups,beinghighest when Ar is m-tolyl and R is CH: or CrH.. No complexis formed when Ar is CtH. and R is cH3 or from dialkyl sulfoximines.However, some dialkyl sulfoximines can be resolvedwith (+)- or (-)-3, 1,6-di(o-chlorophenyl)-1,6-diphenylhexa-2,4diyne-l,6-diol.This reagentis availablecommerciallyas Chiral Host Ace'2 CuH.Cl-o

QuHoCl-o

cuH,-E-c-c-c-c-i-tu", OH

OH

CI3CCHO + CH':Q1QP.;.

I K. Maruoka,T. Itoh,T. Shirasaka. anrjH I K. Maruoka,Y. Hoshino,T. Shirasa\a. er ( le88).

Diisobutylaluminum2,6-di-r-bu(vl-l.rr Diastereospecific reduction of et t lichenmacrolide( + )-aspicilin(4) is rhc dienol 3 with Yamamoto'sreagenr( I I OsOoand pyridinefollowed bv HS red

3 I K. Mori andF. Toda,Chem'Letters,1997 (1988)' : UbeIndustries, Ltd., Tokyo,JaPan' 14, 462,2'-Dihydroxy-3,3'-bis(triphenylsilyl)1,1-binaphthyl-Trimethylaluminum, binaphthol 1. The 47. Thesetwo reagentsreactto form the aluminumnaphthoxide

(1) ])o,.", si(c6Ht3 by conversionto the bis(triphenyl' is preparedrfrom 3,3' -dibromo-1.-1'-binaphthol /-butyllithiumto 3,3' -triphenylwith sitytoxy;ether,whichrearrangeson treatment Al(cH3)3 of sityt-i,t,uinaphthol (80-95Vo yield). Reaction this binaphtholwith dibromobinaphstarting the of prtvides the naphthoxide1. Both optical isomers with a chiral thol are known, or racemicI can be resolvedby a kinetic resolution ketone. Asymmetricene rcactions.2 The reaction of alkeneswith prochiral, electrondeficientaldehydescanfurnishopticallyactivehomoallylicalcoholswhencatalyzed In the by (+)- or (-)-1 and in the presenceof activated4-A molecularsieves, is complex organoaluminum of the absenceof the sieves,a stoichiometricamount yields' essentialfor high chemicaland optical CH"

t -

C6F5CHO+ C,-SC6H5 tl CH,

( R ) - 1 , 4 -MAs 'iii'ii::;;i:, s8%

c6F5y,.\r,sc6H5 |

ll

OH CH, (EtVoer')

G. Quinkert, N. Heim,J. Glenneberg. U. D G. Zimmermann, J. W. Bats,andG. D0ra

Diisobutylaluminum hydride (DIBAH t. II y droa lam ination of a-t- bu toxlcla .!her of propargylyicalcohol or of rhc Jrnationyieldsexclusivelythe correspon t )n the other hand, if the t-butoxygroup

Jrirtth!

Diisobutylaluminum hydride

hluminum

r \r rnd R grouPs,beinghighest nr,.\ is formedwhenAr is CoH' rc\.r. somedialkYlsulfoximines orr.r henyl)-1,6-diphenylhexa-2,4nrl.r as ChiralHost Ace'' C.H.Cl-o

-----^-+ CI3CCHO+ CHr:Q1g11:)z 'L leco

I37

ClrCtln'CHa I

oH

ll

cH,

eel [(S),78Va ' K. Maruoka,T. Itoh, T. Shirasaka, and H. Yamamoto,Am.,Soc.,110,310 (1988). r K. Maruoka, Y. Hoshino,T. Shirasaka,and H. Yamamoto,Tetrahedron Letters,29,3967 ( 1988).

-c-c6H5 Diisobutylaluminum2,6-di-t-butyl-4-methylphenoxide (l), 9, 17l. Diastereospecificreduction of an enone.t A key step in a synthesisof the lichenmacrolide( + )-aspicilin(a) is the reductionof the oxodienelactone 2 to the dienol 3 with Yamamoto'sreagent(l) in 967o yield. Dihydroxylationof 3 with OsOoand pyridine followed by H,S reductiongivesthe triol (4) in 40% yield.

OH

fthl l-TrimethYlaluminum, 14, 46un: nrphthoxide1. The binaphthol I, C6H{CH1 _-.j--j-----:-'

96%

L .

KH

(T)

ft br ;onversionto the bis(triphenylrr: :. :-butyllithiumto 3,3'-triphenylr .': rhis binaPhtholwith Al(CHr)' r:. ..f the startingdibromobinaph' br : krneticresolutionwith a chiral t: :ikeneswith prochiral,electronhr:..allylic alcoholswhencatalyzed the ir'::.1 4-A molecularsieves'In is comPlex t .-: :he organoaluminum

'-

c.r. -rzL,sc,Ht l t l oH cH' (887o eB)

G. Quinkert, N. Heim,J. Glenneberg, U. Doller,M. Eichhorn, U.-M.Billhardt, C. Schwarz, G. Zimmermann, J. W. Bats,andG. Dtirner,Helv.,7l,1719(1988). Diisobutylaluminum hydride (DIBAH). Hydroalumination of a-t-butoxyalkynes.I Hydroaluminationof the o-r-butyl cther of propargylyicalcohol or of the homopropargylicalcoholfollowed by ioJinationyieldsexclusivelythe corresponding (Z)-vinyliodidesbecause ofchelation. On the other hand,if the t-butoxygroup is separatedfrom the triple bond by three

2,2-Dimethoxypropane-Tin(Il)chloride

givesexclusively(E)-vinyl or more methylenegroups,hydroalumination/iodination iodides.The /-butoxy group is convertedto an acetoxygroup by reactionwith AczO/FeCl,in ether in 87-93Voyield. This hydroaluminationis a usefulreaction for synthesisof severalpheromones. 1) DIBAH

HC:c(cH2)"oc(cH3)3

2)tz

62J4%

> ICH:CH(CIL),OC(CH3)3

l, co+ 65.5o

(2, >99Vo)

n=1,2 n = 3-10

(8, >99Va)

I A. Alexakisand J. M. Duffault, Tetrahedron Letters,29,6243(1988).

are preparedin 98Diisopropylcrotylboronates,1..Thesechiral crotylboranates 99% ee from diisopropyltartrate. COO-i-Pr

P
99:1

8 8 Veoe

1:99

CH, 824oee

of both (E)- and (Z)-l decreases caseof (Z)-1. Moreover, the enantioselectivity in reactionswith p-alkoxyaldehydes(72-85Voee) and aromaticor a,B-unsaturated aldehydes(55-77Vo ee). I W. R. Roush,K. Ando,D. B. Powers, Tetahedron andA. D. Palkowitz, R. L. Halterman, 29,5579(1988). Letters, 2,2-Dimethoxypropane-Tin(Il) chloride. Isopropylidenation.r Reaction of o-glucono-1,4-lactone(1) with 2,2-dimeth' oxypropanecatalyzedby SnCl in DME resultsin the ketal in57Voyield. Periodate an attractivechiral cleavageof 2 leads to (R)-O-isopropylidineglyceraldehyde,

synthon.This route via o-glucoa usualroute via p-mannitol.

G. J. F. Chittenden, Rec.Trav..lJ

I, l.Dimethoxypropene, CH.CIF 2r2-Dimethoxyoxetancs.t In hydroxyaldehydesto give 2,24u, hydroxy-3-methyl-D-lactones and activelactonewasobtainedin &)9 OAc CH3CHCH2CHO + CHrCH:C(fr

1,1-Dimethoxypropene

(E)-vinYl on r\ esexclusivelY k \\ group bY reactionwith rn::.ttion is a usefulreaction

gHroH

"o-

Vo\^,.li}r.,,ffilf,, 3ir:x37Zo\ \o "

Y

:lr,cH:)"OC(CH3)3

fo'

si%

OH

l, oo+ 65.5o

Y

fo

^

OH

2, ao+ 76"

Z. >WVo) '-. >99Va)

r--:

\o"

I Ndo. 7r%JNHcq

cHo

r l9tt8).

kowt",

l__oncH,

are preparedin 98xrrr.:rJt€s

3, co+ 63o

n--2

coo-,-Pr

/""COO-t-Pr

-.8'

synthon.This route via n-gluconicacid is economicallymore attractivethan the usualroute via o-mannitol. G. J. F. Chittenden, Rec.Trav.,f07,455(1988).

i r - R . R , - l ( 9 9 V oe e )

to form I rc.'ctswith aldehYdes a:; rZ)-l showsequallYhigh lessin the c.::\ 1I! iSSOmewhat OH

I s'^-'-Acn" r' |

"

CH,

1,l-Dimethoxypropene,CH3CH:C(OCH.),. Supplier:Aldrich. 2r2-Dimethoryoxetanes,r In the presenceof ZnClr, this ketal reactswith phydroxyaldehydesto give 2,2-dimethoxyoxetanes, which can be convertedinto 4hydroxy-3-methyl-D-lactones and 5,6-dihydro-2-pyrones. In one case,an opticaily activefactonewasobtainedin80vo ee from an opticallyactive1-hydroxyaldehyde.

9A. CH3CHCH2CHO+ CH,CH:C(OCHr),

zrctz,

82Voee

b...th(E)- and (Z)'l decreases nJ rr(rmaticor a,B-unsaturated

[-cH,oc-ocH,-cH2-cH-o

I

H

L

Tetrahedron . ::- .\. D. Palkowitz,

l..i-.-tclone(1.)with 2,2-dimethDeieral in57VoYield'Periodate rr.Jeh\de, an attractivechiral

cqtrocH3l

sMI l ) K o H fzix'o.

(oYo

\,Acr

""o' '* (o\o

Y.", OH

I

ocH3l

DL.tr l4l)

Dirnethylaluminum 2,6di'r'butyh4'methylphenoxide

crt

OCH(CH3)OCrHs CuHr:.rO-ZO

----+ cuH,CH-cucHo oI?

t

I

cH'"Y

cH,

r., lvn *I 1 " ' * * ' cHo

cu'

oH

(anti)

( 4 :l )

BE.O(qH+ I (cH3tAl DAD MAD

and R' J' F Nivard' J'c's' Perkin l' 2315 rR. G. Hofstraat,J. Lange,H. W. Scheeren, (1e88).

(L)' (R,R)-(+ )-2'3'Dimethoxy'N,N,N',N''tetramethylsuccinamide m.p.61-62',ca * 115'' coN(cH3)2

u-l-ocs,

in a further increasein endo-selectivitr. B MAD [methylaluminumbis(2,Gdi-r-bur ers the endo-selectivity. The usual rule of endo-selectiitv is m pentadienewith methacrolein(equationll enhanceero-selectivitybecauseof stericI

cH3o-f H coN(cH3)'

cH'

(rr) O.t-.",- L

I

tartrate by reactionwith diThe reagentis preparedfrom (R,R)-(+)-diethyl and 2,2-dimethoxyprosulfate (dimethyl methylamiriefollowed by methylation pane). (2)' The succinamide1 forms Resolutionof 2,2''dihydroxy-1,1''binaphthyl The temperaturein benzene/hexane' an insoluble1:1 complexwith (t)-2 at room (s)-( - )gel furnishes silica on complex after recrystallizationand chromatography from the filtrate' 2of l00Voee. (n)-(+;-Z of ft\% ee can be obtained (1988). andM. Niven,Chem,Leuers,1371 lF. Toda,K. Tanaka,L. Nassimbeni,

Dimethylaluminum 2,6'di'r'butyl'4'methylphenoxide

(DAD)'

CHO

(cq)!Al 64* DAD 67* MAD 76*

the diene, rather than by an electronicel dienophile,as in the reactionwith acroh An even greater steric effect of thc I organoaluminumreagents4-6 in the Dicl diene(equationIII). OCH" I

tn"\-/

cE (1)

(cHJ2Al-o

5 5 '

Bu-t Diels-Aldercatalyst.TheDiels-Alderreactionofcyclopentadienewith gives a mixture of'endo- and exo' acrolein (equation I) catalyzedby BFr etherate is improved by use of trim_ethylaluadductsin the ratio g: 1. The endo-selectivity aluminum by use of DAD results minum. Introduction of a more bulky group on

rllll

l)qHjctlo'* t-

2)cF{mtl ---

i (cH3)3siocH" +4 +5 +6

72* 9r% u%

Dimethylaluminum2,Gdi-r-butyl-4-methylphenoxide

ol O.

Q H r N c6H5cH3'-?8o' Nu ,fl ^ ' >

vr

CH

cHo

+ exo-2

I cHo endo-2

f ; . . / . C ' .S .

BF3.O(qHs)' (cH3)3Al DAD MAD

Perkin 1,231'5

ride(1),

\D r.

H

^

N

N

/\\ /\\ (u)[=/ . li"' ----lD-__l.cHo _+lD-[cr, ?-.", 5:r iuo J", J"o

arc h) reactionwith diand 2,2-dimethoxYPro-

n a . , .i 3 7 1( 1 9 8 8 ) .

9:1 24: I 32:1 1 2 :I

in a further increasein endo-selectivity. But useof the evenmore hinderedcatalyst MAD [methylaluminumbis(2,6-di-r-butyl-4-methytphenoxide), 13, 203-206]towers the endo-selectivity. The usualrule of endo-selectivity is not observedin the cycloadditionof cyclopentadienewith methacrolein(equationII). In this reactionboth DAD and MAD enhancee.ro-selectivity becauseof stericrepulsionbetweenthe bulky catalystand

C

te :uccinamidel" forms The in renzene/hexane. ca gel furnishes(S)-( ),m rhe filtrate.

46% 577o 52Vo 56Vo

exo-3

endo-3

+ (CHr)rAl 64Vo DAD 67Vo MAD 769o

1 5 :I 24:.1 49:1

the diene, rather than by an electroniceffect involvingthe carbonylgroup of the dienophile,as in the reactionwith acrolein. An even greater steric effect of the Lewis acid catalystis observedwith the organoaluminumreagents4-6 in the Diels-Alder reactionsof an aldehydewith a diene(equationIII).

ocH t

cHtJ (lll)

l'

(cH"),sio^

3

a1u

l o4ac6H5

I cH3

oi *cloPentadiene with nr\ture of endo- and exo:d r\ useof trimethYlalurn br use of DAD results

".,,-Z\o

"".\4o r)c6H5cHo'€L tr "t'"*n ' t

+ o

cH3 72% 9r% 84Vo

l : CH, trans-7

cis-7

+4 +5 +6

l

l:l t . 1

1 2 :I

c6H5

DimethYloluminum

' K. Mikami.T.-P.Loh. andT. Nakai.Icrn

Dimethyldioxirane,12, 413; 13. 120. Arene dioxides. Arene dioxides I polycyclicarenes,but someidentifiedn ides.Arene dioxidescan be obtained\ bondcomparableto the 9,I0-doublebo with dimethyldioxirane(f), but in mod by this method,but can be obtainedrr

4,R=CHr 5' R, = Me.,-t-Bu 6, R = CeHs 1453(1988). lK. Maruoka,K' Nonoshita,and H' Yamamoto'syn. Comm.,18,

Dimethylaluminumtrifluoromethanesulfonate,(cHJtA-loTf' - .:^-^ Gtyorylateeneneactions.Thediastereoselectivityoftheenereactionofmethyl acid be controlled by the choice of the Lewis glyoxylate (L) with 2-b";;; (2) can quanin proceed with either (E)- or (z)-2 catalyst.Reactions""t"1;;;;';; Sncr, The reactioncatalyzedby (CHJtAlCl tative yield and fairly t"gi'y'-t"ft"tivity' particularlyin the reaction anri-selectivity, proceedsin low yield tszij uut *itr, high CH"

t " ? cH2cr2QH, CH tl * u d c o o c n r 4 l l CH

l

I

c

H

CH, ) D

z E

z

CH"-

oH

|

r

Y A

ocH3 *

ll

lOocu,

iH. b sYn-3

antlS

82:18 72:28 2l:79 9;91

1007o lNVo 29Vo 65Vo

SnClo SnClo (CH3)2AIOTf (CH3)2AIOTf

OH

4

in the dimethylaluminumtriflate' particularly with (E)-2. Higher yieldsobtainwith case of (Z)-2.

:

^r +L^ .i.r- nhoin n

Thisenereactioncanbeusedtoeffectsynthesisofthesidechainpresentln (equationI)' the plant growth brassinosteroids

coocH3

CH:-cH.il (l)

\

\ I

l

l

o (cHl),Alcl

l+HCCOoCH, (2)

61E"

(anti, lC0To)

Aflatoxin Bt epoxide,2 This epor carcinogenicity of aflatoxinB,, has ber

Dimethyldioxirene

143

' K. Mikami, T.-P. Loh, and T. Nakai, Tetrahedron Letters,29,6305 (1988).

Dimethyldioxtuane, ll2, 4\3; 13, 120. Arene dioxides. Arene dioxideshave not been identifiedas metabolitesof polycyclicarenes,but someidentifiedmetabolitesmay be formedfrom arenedioxides.Arene dioxidescanbe obtainedby reactionofpolyarenescontaininga double bondcomparableto the 9,10-doublebond of phenanthrene(suchas2) by oxidation with dimethyldioxirane(1), but in modestyield. The dioxide5 cannotbe obtained by this method,but can be obtainedvia a trans,vig-bromoacetate.r

ICH.

(1988)' | ( n m . . r E ,1 4 5 3 t( Il r-AlOTf. c':rrrlr of the enereactionof methyl ei :r the choiceof the Lewis acid x: t:)- or (Z)-2 Proceedin quanbY (CH)rAlCl r3.,.lroncatalYzed in the reaction r.:.\ rt\ . particularly

xH,

CH' lly

+

l

$ . 5 , b " '6q "% "%

OH I ryocH3

CH,

l

l

o

^ v

sYn-3

l) NBA LiOAc 2)NBs 3) NaOCHI 6Va

il: l8 -2:28 ll:79 9:91 4

5

in the t.-::'rnumtriflate,particularly in Tr:-r-r. rrf the sidechainpresent )

Aflatoxin 81 epoxide.z This epoxide (2), which may be responsiblefor the carcinogenicity of aflatoxinB,, has beenpreparedby reactionof aflatoxinB, (1)

o-o

coocH3

(anti, 1007a)

(cH1bc=o #

l4

N'O-DimethylhydroxYlemine

with thoroughlydried (molecularsievesor Krco3) solutionsof dimethyldioxirane in acetoneor cH2cl2. The epoxideis very sensitiveto water, but can be storedat -10.. The epoxide(2), the first known epoxideof a tetrahydrofuran,reactsvery with the guanineunit of DNA to form an adductat the Nlposition. specifically ' under a variety of RNCO -+ RNOr.3 Ozonedoesnot reactwith isocyanates mixtures' Surgives complex conditions;oxidationwith KMnO, or CIC6HaCO3H in acetoneaffordsnitro compoundsin surprisingly prisingly,oxidationwith oxone@ i,lgf, yi"fO. from both aromatic and primary, secondary,and tertiary aliphatic p*.uiro.r. Water is an essentialingredient,probablybecausethe oxidationprois ceedsthrough the carbamicacid, which then losesco, to give an amine that be can oxidation this the immediateprecursorto the nitro compound.The rate of byo addition greatly _ A t N Hincreased z.-->ArN z . a T h i sof o xTriton i d a t i oB.n c a n b e e f f e c t e d w i t h d i m e t h y l d i o x i r a n e generatedin situ from oxoneoin acetone(1-1.,442).However, in somecasesthe intermediatenitrosoarenecan be the major product, especiallywhen a limited amount of Oxone is employed.In such casesthe yield of the nitroarenecan be improvedby addition of certainaromatics,suchas indolesor furans. (1) Nifioxides.s Cyclic secondaryaminesare oxidizedby dimethyldioxirane

llvll . CHr'.|

coNH;l

l-

lrCH,

I T. Hanamoto and T. Hiyama, T.t)

cH,../-\zcH, ,

l

I o.

OH

-..

+ CH'C

coNH2

, t*rzrrlo,o'rp?::,;;'.".Ad.""

OH

o ll (CH.1"6:9116p--ocu,' -a",

l,3.Dimethyl.2-imidazolidinoc flX

to nitroxidesin yields >95Vo. coNH2

productsare reducedto g.Mihy ethyl(methoxy)borane.

Ullman ether synthesis.t m-p condensation of z-hydroxybenz_v d and8-hydroxyquinoline (a). Thc yr highestin DMI.

"o\

/--.,

cH,rl

lzcH,

cH,A54cH, #.n,AT^.", o.

rS. K. Agarwal,D. R. Boyd, W. B. Jennings'R. M' McGuckin,and G' A' O' Kane' Leuers,30, 123(1989). Tetrahedron 2 S. W. Baertschi,K. D. Raney,M. P. Stone,and T. M. Harris,Am. soc., 110,7929(1988). r P. E. Eatonand G. E. Wicks,,r. Org., 53,5353(1988). 1D. L. Zabrowski.A. E. Moormann,and K. R. Beck,Jr., Tetrahedron LeUers,29,450l ( r988). 5 R. W. Murray and M. Singh,ibid.,29,4677(1988).

LL, 201-202. N,O-Dimethylhydroxylamine, p,6-Diketo esters.t Various N-methoxy-N-methyl amides couple with the dianion of alkyl acetoacetates to form B,6-diketo esters in 42-9lVo yield. These

UFcH,oH

+ ql DMF DMSO DMI

R. Oi, C. Shimakawa,and S. Takcoe

Dimethylphosphinothioyl chloridc, r Peptide syzdresis in mertotol e hydrides prepared from N-protedc alcoholsin the absenceof a base.p sequencethese active esters can h

Dtunethylphosphinothioyl chloride

\'.utronsof dimethYldioxirane I '.' \\ater.but can be storedat i .: :ctrahYdrofuran'reactsverY a: ,r,lductu115s\LPosition' undera varietyof I r.,)c\anates i'{ rr\d\ comPlexmixtures' Surin surPrisinglY nr:r,, comPounds c\\:.Jrr). and tertiarY aliPhatic the oxidationProa!..r trecause 11( (). to give an amine that is fhs r.rteof this oxidationcan be lits.:cJ with dimethYldioxirane l, llowever,in somecasesthe du;: especiallYwhen a limited : rrti,j of the nitroarenecan be !. i:lJolesor furans. (1) rr;rzc,JbY dimethYldioxirane

) \ l t ' ll

/.coNH2

i r l , cur.rnu'cH' H

7

l

.l

a""AN " l

cn,

o.

productsare reducedto 8,6-dihydroxyestersby NaBHo in combinationwith diethyl(methoxy)borane.

o

Yt-ocu'

fl fl

lli'fl

(CH.),C:CHCN+CHTCOCHTCOOBu-I -cH, #(CH,),C:CHdCUTCCnCOOnu_, "

N!aH1 | (c2H5)2BocH3, JrHFrcH3oH

OH

OH

: cH\-'t'-(CH,)rc

cooBu-I

synlanti>95 :5

I T. Hanamoto andT. Hiyama,Tetrahedron (1988). Letters,29,6467

It-Dimethyl-2-imidazotidinone (DMI),

-*/c't 't | \NAo

0), tl, Z0Z.

CH, Ullman ether synthesis,t ru-Phenoxybenzylalcohol (3) can be prepared by condensation ofz-hydroxybenzylalcohol(2) with chlorobenzene catalyzedby cucl and 8-hydroxyquinoline (a). The yield is markedlydependenton the solvent,being highestin DMI.

2

It

1.15

DMF DMSO DMI

2r% 58% EI%

3

\tcGuckin,and G' A' O Kane'

d li.:rrrs.Am. Soc.'1f0,7929(1988)' F\ Leuers,29,450l irr ir Tetrahedron

' R. Oi, C. Shimakawa,and S. Takenaka,Chem.Letters,899(1988).

S

tl Dimethylphosphinothioyl chloride,CIP(CH3),(1.).

-rr.r:hrl amidescouplewith the diIr. :.rr-rsin 42-9lVo Yield' These

Preparation.' Peptide synthesisin methanol or ethanol.2 The dimethylphosphinothioicanhydridespreparedfrom N-protectedamino acids with 1 are stableto water or alcoholsin the absenceof a base,probablybecauseof the I,:S bond. As a consequencethese active esterscan be used for peptide synthesesin methanol or

L6

Dirnethylsufoxide-Phenyldichlorophosphate

ethanolratherthan the dipolar aproticsolvents(HMPT, DMR or DMSO) usually required.The report includesa synthesisof a heptapeptideby this expedient.

cH2cr2

.,/\

I

llal

- z o + z r/ r l

\-/

' M. Ueki,T. Inazu,andS. Ikeda,Bull. Chem.Soc.Japan,52' 2424(1979). ' M. Ueki,T. Saito,J. Sasaya, ibid.'61'3653(1988). S. Ikeda,andH. Oyamada,

804

CH3(CHJ"CH:CH, n=11or15

Dimethyl sulfoxide-Chlorotrimethylsilane. Cleavageof a,p-epoxyketones.t The reagent(1), possibly(CH,)rSCl'formed from DMSO and ClSi(CHr)r, cleavesa,B-epoxyketonesto 2-chloro-3-hydroxy ketoneswith high regioselectivity(equationI). If the epoxidehas a phenyl subketonesare formed (equationII). stituent,3-chloro-2-hydroxy

cl \ .cH3 H O-.1\zo .

o I, CHTCN,25' 9l%

ctr(cE),

(rr)

A/COCH3 CuHt

t

V

l

cH(cH3)'

c l o t t l

' F. Ghelfi,R. Grandi,andU. M. Pagnoni, J. Chem.Ras.(S)' 200(1988).

Dimethyl sulfide-Dibenzoyl peroxide. 'these ethers(6,1O9-\\S) canbe prepared Methylthiomerhyl (MTIlf) ethers.l by reactionof alcoholswith dimethylsulfide(8 equiv.) and dibenzoylperoxide(4 equiv.) in CH.CN at 0" (75-90Voyield). Excessdimethyl sulfideis requiredsince someof the sulfideis oxidizedto dimethyl sulfoxide. rJ. C. Medina,M. Salomon, (1988)' Letters,29,3773 andK. S. Kyler,Tetrahedron

i (C6H5OPCI2)' dichlorophosphate

Dimethy!sulfoxide-Phenyl p-chloroalkyl sulfides.t A reagent(1), obtainedfrom DMSO and cuHsoPocl: with alkenesin which the methylthiogroup in CHrCl, at -20",forms trans-adducts carbonatom. is attachedto the less-substituted

F

I H.-J. Liu and J. M. Nyangulu, Tetrahedrott

o

Dimethylsulfoxonium methylide,CH,:i Cyclopropanationof lactams.t Th$ 2 (13, 18-19) to form endo-cyclopropana are hydrolyzed to optically active c-vclop

""'Y"oqu \,o7rt q,.uYA_ +

7c.",Yc",

I OH

\

I

o , R=H R = CcHs

644o s8%

t 95t 931

A. l. Meyers,J. L. Romine, and S. A. Flcu

Dimethyl 1,2,4,5-tetrazine-3,6-dicarbox

The tetrazineis preparedin severalsteps Diels-Alder reactionslpyrroles.. n :ronwith unactivateddienophilesto form rhich are reducedby zinc in aceticacid r i.5-dicarboxylates.

Dimethyl 1,2,4,5-tetrazine-3'6dicrrboxylete

7\ I

{\tPT. DMF, or DMSO) usually ptulc-PtidebY this expedient' t;i' 1l.l:

cH2cr2 ^,"'tt l l+ 1 - 2 0 + 2 0 " ) l I

,os' 9ra",

\-/

s2.2424(1979). t b r d . . 6 1 , 3 6(5139 8 8 ) '

cH3(CHt"cH:CHz

rou"*

Cnr(cH2)"9H-CHTSCH3

n=tlorl5

formed nr , 1 r. possibly(Ctt,)'3Ct' 2-chloro-3-hYdroxY n icr.',nesto subi: rhe ePoxidehas a PhenYl I I ) ' rc q u a t i o n cl , .cH3

0 )-yo

I

v/I

cH(CH3)'

o cl ll '\z'^cH, 'r., I OH , . 5 ) .2 0 0( 1 9 8 8 ) .

L47

Cl

I H.-J. Liu and J. M. Nyangulu,TetahedronLetters,29,5467(1988).

fl

Dimethylsulfoxonium methylide,CHr:S(CHr), (1). Cyclopropanationof hctums.t This reagentaddsto the chiral bicycliclactams adducts(3)in>93Vo de. Theseadducts 2 (13, 18-19)to form endo-cyclopropanated (4). are hydrolyzedto opticallyactivecyclopropanes

CHr-OzcHrgg,

CH,-OzCHrg11,

Voi--n A,^ly^* -!

.fr$ii^, cH, R

8l-t8%

cH3ooc

o

o , R=H R = CcHs

\P-N \*\.4i l '

64Vo 58Vo

3 95Vo ee e 93Vo

A. I. Meyers,J. L. Romine,and S. A. Fleming,Am.$oc.,110,7245(1988).

be I c::.rr\ (6. 109-110)can PrePared peroxide(4 dibenzoyl and ,j ..r't.) since r.- .:'methylsulfideis required il:.'r.Je (1988)' t ""',t1 Letters,29,3773

(J

il : , .tl.OPCIJ. C.H5OPOCI: 1,.,...,r from DMSO and grouP methylthio the which a.\i:..r in \r

coocHr NAN Dimethyf1,2,4,5-tetrazine-3,6-dicarboxylate, ll | N-..ZN

(l),

m.p. 173-175".

I coocHs The tetrazineis preparedin severalstepsfrom ethyl diazoacetate. Diels-Alder reactionslpyn'oles.t This azadieneundergoes[4+2] cycloaddi:ronwith unactivateddienophilesto form dimethyl I,2-diazine'3,6-dicarboxylates, .hich are reducedby zinc in aceticacid with ring contractionto dimethylpyrrolei .5-dicarboxylates.

3,S-Dlnitroperoxybenzoic ecid

cH" il" 1+

CuH,

dioxu

i

coocH3

.u

s2%

v

coocH3

r+

lI CH,

------+

";H

63% ^,, Lrl

CH,

\ coocH3

NH

| )=/ \

coocH3

rD. L. Boger,J. S. Panek, (1988)' andM. Patel,Org.Syn.,submitted Dimethylzinc' Zn(CH3)2. Enolate acylation and alkylation.t The yield from acylation and alkylation of lithium ketoneenolatesis markedlyimprovedby additionof dimethylzinc.which

o tl

oLi

I

A IJ

cHrr (

;\J

)--cH'

+ HMPT 94Vo + 7n(CHr), 98%

o il

oLi

A

4

csHlTcocl 7a(CH$

ococsHr?

ccsHrT lrH,t

+

7^.

l

l

\-/

\-, (88%)

I

4

o_N

C^H., - "\./

coocH3

. ,"_Or\ r r l

cH,

If

l(5 cquia.I cH{t

.-

@_"o"syz\*

colr,/-\osi(cH3)3#

cH3\ /osi(cH3)3

cuH',6cH,

I

(tco)

suppressesa-proton exchange.The effective reagent may be a lithium alkoxYdimethvlzincate. rY. Morita,M. Suzuki, andR. Noyori,J. Org.,54'1785(1989). 3,S-Dinitroperoxybenzoicacid' (OrN),C6H.CO3H(l'). Cleavageof isoxazolinesto $-hydrory ketones.t This cleavagecan be effected acid (1) or trifluoroperaceticacid usingabout 5 with either 3,5-dinitroperbenzoic equiv. of the peracid at 25'. Use of more drasticconditionsresultsin BaeyerVilligar oxidationof the B-hydroxyketonesto acylateddiols.

&

I P.ParkandA. P. Kozikowski, TerrahedrcI (Dioctyl)sodium sulfosuccinate,

s I cH3(cH')3cH(c,H5)cH'O'CCH:CHC .( (AOT,r).

Selectivepeptide synthesis.t Thrs sur from certainaminoacidsin isooctanewau or dioctadecylcarbodiimide (DODCI). Thi hydrophobicgroupssuchasleucine.(CH.) and TrpOCH, coupleto form a dipepti& waterto the extentof LlVo,but whenAO Trp-OCH1 is formed in 60Voyield. In rlx This coupling effectedwith a surfactanrsr aminoacid are alignedat the micellarsurfr are in close promixity and that formation facilitated.Couplingis not promotedwhcr DCC or DODCI. This techniquecan be usr .rn the basicityof two differentamino acid D. Ranganathan, G. p. Singh,andS. Ranga

l.'l-Dioxene, 13, Il2-1I3. a-Hydroxy and u-keto acids.t The pr ietoneswith lithiated1,4_dioxene areoxidu :cids (2). Oxidationof the adductswith Fc

iffil=-"11, \o/

tto

o

1,4-Dioxene

cH, z^ HoAc

.IJ v6r^5\z^ ,

I

-NH

rrs equiv)cH2Cl2 C6H'3',-VCH3

CuH,r\.*CH,

I

O -N

ll

"------+

-----:^

56Eo

|

ll

OH

O

I

i2c'o

i

coocH3

\/

* lt3"r"i"l' cucL f

\ coocH3

cH,

cuH,r-a,^.oA.

I, .1r "":\4 ----------, -r+

coocH3 I NH

I ):/

C H-" ' H.

\

coocH3

L49

I

OH

* 7:3

CuH'r\ioH OAc

rP. ParkandA. P. Kozikowski, (1988). Letters,29,6703 Tetrahedron (Dioctyl)sodium sulfosuccinale, SO.Na

!J.mrtted (1988)'

ne.i from acylationand alkylation which lbr .rJditionof dimethylzinc'

ococsHrT

CH3(CH')3CH(C'H5)CH'O'CCH'CHCO'CHCH'CO'CH'CH(C'H'XCH2)'CH3 (AOT,1). Selectivepeptide synthesis.t This surfactant can effect synthesisof peptides (DCC) with dicyclohexylcarbodiimide from certainaminoacidsin isooctane/water (DODCI). This couplingis limited to aminoacidswith or dioctadecylcarbodiimide hydrophobicgroupssuchas leucine,(CH.)'CHCH,CH(NHr)COOH.Thus Bzl-Trp and TrpOCH, coupleto form a dipeptidewhen activatedwith DCC in isooctane/ waterto the extentof lTVo,but when AOT is alsopresentthe dipeptideBzl-TrpTrp-OCH1 is formed in 60Voyield. In the absenceof water, no reactionoccurs. This couplingeffectedwith a surfactantsuggeststhat DCC and the hydrophobic aminoacid are alignedat the micellarsurfacein sucha way that both polar groups are in close promixity and that formation of the activatedester intermediateis facilitated.Couplingis not promotedwhen a water-solublecarbodiimidereplaces DCC or DODCI. This techniquecanbe usedto effectselectivecouplingdepending on the basicityof two differentamino acids. \oc.,111,1144(1989). G. P.Singh,andS. Ranganathan,Am. D. Ranganathan,

(89o) alkoxydirc,:iclll may be a lithium

|

.-.

s

ll o

AcO

which is oxidizedby PCC to an c-keto ester,which is hydrolyzedto an c-keto actd (st. IM. Fetizon.P. Goulaouic, (1988). Letters,29,6261 andI. Hanna,Tetrahedron Diphenyliodoniumchloride, (C6H,)2ICI,l, 341. ; 2, I78. Phenyl arenedithiocarboxylates.t These esterscan be prepared by reaction of diphenyliodoniumchlorideor bromidewith sodiumarenedithiocarboxylates. S S ll ll '-nrInH?no ercSCr4 nCSNa + (CuH,)rICl #

"o.xK,. (-j--,

Diphenylphosphinicchloride (7, 138). p-Lactamsfromp-aminoacids.t B-Aminoacidscyclizeto B-lactamson treatand triethylamine(1:1) in CH.CN at 80" usuallywith ment with (C6H5),P(O)C| of the amino acid. However,yieldsare rather preservationof the stereochemistry low when the amino group is primary.

I R. L. Dorta,C. G. Francisco, R. Freirc.arr ( 1e88).

OAc

o

,oAc

fr

cuffc,H, HOOC NHBzI

---;-

/H

cH4-1-con, "-Brl

O'/

Diphenylseleniumhydroxyacetate(CoHr)r*d:-ococH"(l).

(c6H5hsiH2.Fdo^ 7^Ch,THF 5EC

I-o

(G5H5)2PC[ N(c.2H5b C6H5O\

F[

Diphenylsilane-Palladiurn(0)-Zinccilorf Reduction of allylic acetates. This ,t reductionof simple allylic acetatesand er PdIP(C6Hs)3]4 is replacedby terrakis(tri-pt

I Z.-C.Chen,Y.-Y.Jin,andR.-Y.Yang,Synthesis, 723(1988).

C6H5OWH

i

/l

I-

o.JL-).",--

N. Greenspoon andE. Keinan,J. Org.53.3?a Diphosphorustetraiodide, prlo. Reductive desulfuration of dithiuccnl ietals can be effectedwith prln. Y.Shigemasa, M. Ogawa, H. Sashiwa, andH. Sl

Diphosphorustetraiodide

*t,

-r .uA/o\ \o/ {

The reagohtis obtainedby reactionof (C6H5)rSeO with aceticanhydridein THF (807oyield). It losesHOAc at 80'. Hypoiodite reaction.t This reaction is usually carried out with iodine and HgO (5, 347-348).A new versionusesiodine in combinationwith this diphenylselenurane,and this versiongivesessentiallyonly cyclicetherswithout any iodohydrinsor other productsencounteredwith other heavymetal acetates.

o

CH"I

tl cH3)TcHCCOOH

f a _

r^J r'12,,,80') atfr so%

eco\A/

"o--,^jX' l

l

\-A--l

_1::t. 178. tk' J.:drs can be preparedby reaction n:- -'Jrum arenedithiocarboxylates'

--

l'" ]

S tl r ercSCuH,

-' ,,*,

on treattr i'- 1.rdscvclizeto P-lactams with usuallY 80' at r CH.CN . rn x " rather yields are However, .rcrd. i1.'

C6HrO\

/H

cHif-l)cuu, of^-B, w.

n,n . 1242(1988).

l l {' ' )' \' r/ , t ' O C H r ( l ) .

l

?r=lr\t l l

*80% l

rR. L. Dorta,C. G. Francisco, R. Freire,andE. Sudrez, Tetrahedron Letters,29,5429 ( 1988).

Diphenylsilane-Palladium(0)-Zincchloride. Reduction of allylic acetates. This three-componentsystemis effective for reductionof simple allylic acetatesand even of 3-acetoxyglycals, particularlyif PdIP(C6H5)3]4 is replacedby tetrakis(tri-p-tolylphosphine)palladium(0).

tcu?'3Jj-l#(o)'' ^"fi ^.6 ,oAc I-O

[,'

A.o4/

I

OH

, u::.h is hYdrolYzedto an a-keto acld l i . . ' , 1 . e u e r s . 2 9 , 6 2(6119 8 8 ) '

f51

,oAc FO

d"",

';-Q.",,1, o.Jt)"", N. Greenspoon andE. Keinan, J. Org.53,3723(1988).

Diphosphorustetraiodide, PrIo. Reductive desulfuration of dithioacetals.t This reaction of dithioacetalsor ketalscan be effectedwith PrIo. (1989). Y.Shigemasa, M. Ogawa, H. Sashiwa, andH. Saimoto,Tetahedron Letters,N,1277

t52

DisodiumtefiscrrbonY[errte

carbonate' Di-2-pyridYl r,/\)

O

a\

in the presenceof Pd(O)andZnCl, they'rea in the polar solventN-methyl-2-pyrrolido

ll (r).

ll I li I \*AoAoAN/

with phosgene The reagentis obtained(907oyield)by reactionof 2-hydroxypyridine and N(C'H,)3in CHrCI/toluene'l a catalyticamount of 4Esterificationz This reagentin combinationwith for esterificationof carboxylic dimethylaminopyridine(DMAP) is very effective acidswithalcoholsorthiolsatroomtemperatures.However,reactionofaromatic andhinderedacidsrequiresseveraldaysatroomtemperature.Frenchchemists reportthatonlythismethodisusefulforesterificationoftheprotectedbaccatin Illderivative(2)with(2R,3S)-N-benzoyl-O-(1-ethoxyethyl)-3-phenylisoserine(3) reactionconductedat 73'for 100 to provide the protectedtaxoi derivative(4)' A hourswith6equiv.ofland2equiv.ofDMAPproduced4inS}vo.yield.Natural agent,is obtainedby removalof the protective taxol, a cancerchemotherapeutic groupsat Cr' and C, of 4' OR

osi(c,H.). P ,EH,I

(I) RX + NqFe(Co).

RqHrb !'

I

Example:

BuBr

r S4{ ?tt

rT. Koga,S. Makinouchi,and N. Okukado.C/r

N-Dodecylpyridoxal(DPL.r,

I C'J

Transamination. Transaminationwrti catalystsuch as Cu(II). However, transar combinationwith hexadecyltrimethylam reagentsphenylglycineundergoestransam tion I).

, R = COCH: c6H'coNH ? .n.Alort

;"' "

c6H5CoNH T**, 3 6c,H,r o__ c.H. i ocHCH3

(I) C6H5CHCOO-+ HOOCCHTC I .NH,

I

oc2H5 4 (1984)' rS. Kim, J. I. Lee, and Y. K' Ko,TetrahedronLetters'25'4943 ,J.-N.Denis,a.E.Green,D.Gu6nard,FGu6rritte-Voegelein'L'Mangatal'andP'Potier' Am. Soc.,110,5917(1988)' Disodium tetracarbonYlferrate' Aromatic ketones(cf.,4,461,

463).t The acyliron complexes (2), prepared

fromNarFe(CO)aasshown,haveratherlowreactivitywithalkylhalides'However'

c6Hrcoc0ol

H. Kondo,H. Tanamachi, and J. Sunamoro. C

N-Dodecylpyridoxal

153

in the presenceof Pd(O)andZncl, they reactreadilywith aryl iodides,particularly in the polar solventN-methyl-2-pyrrolidone (NMp).

i rl).

i-hr droxypyridinewith Phosgene

(I) RX + NarFe(CO)o

P(c6H5)3' NMP t RCOFe(CO)rp(Cu4)rl

I

pq *rlh a catalyticamount of 4re r()r esterificationof carboxylic 5 Houev€r,reactionof aromatic [n :.mperature.French chemists hr.rlr(rnof the protectedbaccatin (3) Irh,'rr ethyl)-3-phenylisoserine 100 73'for at conducted rc.ritron 4 in 80Voyield. Natural pr,..1uced of the Protective br removal inc'J

'

t

ss-as* frfic.H,y,1 z,cr" J RCOAI

Example: BuBr

r

ceHslrBuCOC5H5 'tr%

T. Koga, S. Makinouchi,and N. Okukado, Chem.Letters,ll4l (19gg\

N-Dodecylpyridoxal (DPL), (l). CH, Trsnsamination. Transaminationwith pyridoxalor analogsrequiresa metal catalystsuch as cu(II). However, transaminationcan be effectedwith DpL in combinationwith hexadecyltrimethylammonium chloride. By using these two reagentsphenylglycineundergoestransaminationwith 2-oxoglutaricacid (equation I).

o

DPL, RN(CH3)3CI

!l

(I) C6H5CHCOO-+HOOCCHTCH,CCOOH --:0''PH8_9--+

.| *NH.

H. I r a{ 1e13(1984). '\ ':irlcin. L. Mangatal,andP.Potier.

"ll o

C6H5COCOOH+ HOOCCHTCHTCHCOO-

.*", H. Kondo, H. Tanamachi,and J. Sunamoto,Chem.Letters,2013(19gg).

(2), prepared i ::r.rroo complexes flrr::r *'ith alkylhalides.However,

o cH,--NA \

tHr\ NH /

a1 cuH,

cH, Ephedrine. (-)-ephedrine hydrochloride Imidazolidinones. The reaction of urea with used as a chiral auxiliary for be can (1),r which provides a chiral imidazolidinone

"'^)r*'. "+*cH, fr-s* o

(+)-l

cHl

c#,

(-)-2

ctt

cH3- -cH3

llBl?*""",**, a\'coocH' ' (( t - t

t"'f{"'

14cu, (r)

--

l' oo-445o

(lR, 2s)

>i:i t l

effectingstereoselectivesynthesisofcitronellicacid(5).Thusreactionofl.with of a methyl cuprate the acid chloride 2 gives ihe unsaturatedamide 3. Addition an adduct (4) furnish to (12,25I) induction to 3 proceedswlth trigtr asymmetric that is hydrolyzedto (-)-citronellic acid (S)''

\ c q

(S)-f (5$t r

H. Roder,G. Helmchen, E. M. Peters. K. Pc Int.Ed.,23,898(1984). : E. Stephan, andP.Cresson. G. Pourcelot, Clr ' C. FehrandJ. Galindo, Am. Soc.,ll0. 6m I

cH3H96H5 + l +

N_CH(CH /

cHrt Y o

"-l-o" i.g,

cocl

HO \

NR.. CH,CI'

'lo%

.",.*/)^,A,"^f'cH' CH, 3 ,rn t""rh.u"rtr, S(cHrb J

""'F{t'

cH" A

Hooc ,) cH,

o li -si1cH,;,

LioH *,*

II

cH,

"r,-*/ffi"' eH, o o

( Ethoxycarbonyl)nitrene. Ethoxycarbonylamino acids.t ( Etho rhermolysisof N(ethoxycarbonyl)-N.O-b *ith ketenesilyl acetalsto form N-protect

- C-os(cHr), C -' . H';. O N-

cH,

(-)-s (4) havebeenpreprotonntion't (R)- and(S)-c-Damascone Dnantioselective paredbyaGrignardreactionfollowedbyenantioselectiveprotonationwithl'and of the ketone from (-)- or (+)-ephedrine'Thusprotonation i,'uott, availaLle (4), respectively. j-z (R)-c-damascone enolate3 with ( + )-r or 1'- turnishes(S)-or r5l

eo.

* l-(cHr)'sil' o

lLqnto 2

F

(Ethoxycarbonyl)nitrene

o

""'-nA*

H

CE

C.H

"Hr\

Hq

h cuH,

I.r-cH(cH3)' cH3 (-)-2

(+)-1

Ir: * rth ( - )-ephedrinehydrochloride rh ,.,n be usedas a chiral auxiliaryfor

\,'coocH, t l

cH'a-rceHs l !

4

..

\

/ \ N N H

.(+

CH"9Li

CH,

CH.

CH.

1) BuLi 2) CH2=CHCH2M8CI -

fr-"H,cH:cH, t

l

\

cH3

cH, 3 (ElZ= 9:r)

(+)

CHr/ Y o 1, co-214.5o

CH.

/,ril\2'" t

t

\

9cH"

ts "

CH.. -CH,?

CH"?

2dll.'J -^.n. t t

l,c. :, .rcid (5)' Thus reactionof I with ar:: .:g 3. Addition of a methyl cuprate (4) Itr - 12. 251) to turnish an adduct

' H. Roder,G. Helmchen, Angew.Chem. andH. G. v. Schnering, K. Peters, E. M. Peters, Int. Ed., 23,898(1984). I E. Stephan, Chem.Ind.,562(1988) andP. Cresson, G. Pourcelot, ' C. FehrandJ. GalindoAm. $oc.,110, 6909(1988). ,

a{t'"'

-t'r,r\ffiH' CHt

O

3 rnr, s(cH:h

.r* |t."rh.ot

iH.

(Ethoxycarbonyl)nitrene. Ethoxycarbonylaminoacids.t (Ethoxycarbonyl)nitrene(2), generatedby (L),: reacts thermolysisof N(ethoxycarbonyl)-N,O-bis(trimethylsilyl)hydroxylamine yield. (3) in25-70Vo with ketenesilyl acetalsto form N-protectedo-amino esters O

rr---'r.AA.acH'

o 1",

cH3 ee) G)-4 (707o

(S)-4(58%ee)

r)

,

-

e0. f - -- ^)i-.-sl1cu,1, -- C-OSilCHr), # -r(cH,),sit?o l c-r-'', .H.o Nl

-oS(CHrh

ol cH:.r=cArOH.t Aromatic aldehr when treatedwith H,O, (30Vo)in the prer catalysts,of which areneseleninic acidsare matesare readily hydrolyzedto phenols.

Hydridotris(triphenylphosphine)copperhexamer (l) , 14,175. Preparation:

' L. Syper,Synthesis,167 (1989). Naoc(c4), + cucl

c6lr5cH3 r [cuoc(cHr),]o

P(C6H5b

"'

t

NaCl+ (CH,),COH [(CoHr)rPCuH]u+ | (50-6s%)

Hydrogen peroxide-Potassiumcarbonrtc. Or idation of 2 -nitrocycloalkanones.. (30Vo)and K2CO. in CH.OH to dicarboq whetherthe NO, group is secondaryor ter

readily in The hydride hexameras a solid is fairly stableto air, but decomposes solution.t ' D. M. Brestensky, Letters, andJ. M. Stryker,Tetrahedron D. E. Huseland, C. McGettigan, 29,3749(1988).

-

H2q, Kfq CH.OH

;;-H

c(cH3)3 Hydriodic acid. Reduction of sulfoxides to thioethers.r Use of hydrogen halides for this reductionwas first reportedin 1909and is still a viablemethod.This reductionhas assumedimportancesincechiral sulfinylgroupsare valuablein asymmetricsyntheses and are eliminatedin two steps:reductionto the ether followed by catalytichydrogenationor metal/ammoniareduction.The first step can now be carried out review (349references). with severalreagents,as shownby this comprehensive

o. No, \Jz r-cH, (

\J

)

- H

R. Ballini,E. Marcantoni, M. Petrini,andG

I M. Madesclaire, Tetrahedron, 44,6537(1988). Hydrogen peroxide. Arenesulfinicacids.r Oxidationof arenethiolsgenerallyresultsin mixturesof sulfinicand sulfonicacids,sincesulfinicacidsare easilyoxidized.Oxidation with

Hydrogen peroxide-Potassiumfluoride. a-Alkylbenzyl alcohols.t An interesru of this type from acylsilanesinvolvesenan Thus the acylsilaneI is reducedby dibora

Hydrogenperoxide-Potassiumfluoride

NCirrrBI can undergo sequential reJ rn THF in the Presence of

1:6il

HrO, (30Vo)in a basic medium providessodium sulfinates,which are stable to HrOr. c6H5sH+ Hro,

c'H'oH' NaoH'H'o' [cuHrsorNa] ror" Hct,n:o J c6H5so2H

otrarnedin high oPticalPurity R,\ . s-1.r1D](i988). lr l{.175.

rT. Kamiyama, andM. Inoue,Chem.Pharm.8u11.,36,2652(1988). S. Enomoto, acid, CuH,SeOrH. Hydrogenperoxide-Benzeneseleninic ArCHO - ArOH.t Aromatic aldehydesundergo Baeyer-Villiger reaction when treatedwith HrO, (30Vo)in the presenceof severalseleniumcompoundsas acidsare most effective.The resultingaryl forcatalysts,of which areneseleninic matesare readily hydrolyzedto phenols. rL. Syper, (1989). Synthesis,167

P(C6,H5)j

cH,,,,-je-, !rd. * (CH3)3COH

Hydrogen peroxide-Potassiumcarbonate. Oxidation of 2-nitrocycloalkanones.t Thesesubstratesare oxidized by H2O2 (30Vo)and KrCO. in CH.OH to dicarboxylicacidsor keto acids,dependingon whetherthe NO, group is secondaryor tertiary.

readilYin ::: hut decomPoses H2q, K2CO3

Letters, Tetrahedron t j \1 Srryker,

#*

4a,a",,,

[i;"

Hooc(cHr)2cHcHrcooH c(cH3)3

oi hrdrogenhalidesfor this rerb,.emethod.This reductionhas syntheses r:.u.rblein asymmetric e:her followed bY catalYtichYr:: .lep can now be carried out n.r\c rcview(349references).

'R. Ballini,E. Marcantoni, (1988). M. Petrini,andG. Rosini,Synthesis,9l5

b g:nerally resultsin mixturesof .'r.rlr oxidized.Oxidationwith

Hydrogen peroxide-Potassiumfluoride. a-Alkylbenzylalcohols.t An interestingsynthesisof opticallyactivealcohols reductionas the first step. of this type from acylsilanesinvolvesenantioselective Thus the acylsilaneI is reducedby diboraneand a chiral c-amino alcohol [(S)-

HOOC(CHr)4CCH3

tl

o

168

HydrosilanerTetrabutylammonium ffuoride

o il -3#L cH,isilcuur;,

I

C6H5(CH3)rSiH, in the presenceof Bu.\l rotrimethylsilicate(TASF, 13, 336) in ap The actualreagentmay well be a hexava and KF are far lesseffectivethan Bu.NF. X nearquantitativeyieldscan be achieved.a as in the casewith methylcyclohexanon

"\..0" cH/\si1cuH,y,

I

2 (94Voee) (95%) I Aqo, DMAP

la H

cni

C.H.

'ou

HzQ' ff CHrOH KHCOT,

soco

4

(r00so)

"\...'tu"t

o

cu/\sitcuu,y, I

tn'

*

t

OAc

l

(

,uonr.",ot

-(

3 (-)-2-amino-3-methyl-1,l-diphenylbutanol-112 to 2 in 94Voee, probablybecause of the bulky nature of the silyl group. Brook rearrangementof the acetateof 2 provides3, which is then subjectedto oxidation with retention of configuration (L2,243-244), 'J. D. Buynak, (1989). T. Hurd,andA. Phan,l.C,S.Chem.Comm.,89 J. B. Strickland, 2S. Itsuno,M. Nakano,K. Miyazaki,H. Masuda,K. Ito, A. Hirao,and S. Nakahama, J.C.S.Perkin1,2039(1985).

c6H5(cH3)rsiH 99% (c6H5)2cH3siH8l% This reduction is cnti-selective in thc n This contrasts with syn-selectivity for rrcu in trifluoroacetic acid.

o tl

c6H5ccHCH3 Hydrogen peroxide-Ttichloroaceticacid. Cleavageof acid-labile protectivegroups.l The reactionof H2O2Q07o, FMC) and CI:CCOOH in CHzCL/r-butylalcohol convertsa dimethyl acetal(1) into a hydroperoxymethyl acetal(a), which can be isolatedbut which for convenience (andsafety)is reducedto the aldehyde 2 in 80Vooverallyield. The sameconditions can effectoxidativecleavageof tetrahydropyranyland trityl ethers.

RCH(OCH3)' I

ctLcL, (cH,),coH 4q' c\ccooH '

F."{f

I

c6H5(cll3hsiH BU4NF

es%

)

cJ{

OAc

o

o

i l l l c.HlfN(c2Hj)2

'qfr

*.

CH,

M. FujitaandT. Hiyama , J. Org.,53. 5.tO55

s(cH:)2,p611g 80%

,

a

in all manipulationswith the safetyprecautionsnecessary The paper discusses hydrogenperoxide. IA. G. Myers,M. A. M. Fundy,andP. A. Lindstrom, Letters,29,5609 h., Tetrahedron ( 1988). Hydrosilanes-Tetrabutylammoniumfl uoride. Redaction of aldehydesor ketones.t This reduction can be effectedwith hydrosilanes,particularly sterically hindered silanessuch as (CuHs):SiHrand

p-Hydroxyethyltriphenylarsoniumbrod saltis preparedin 69Voyield by reacriono 2,3-Epoxy-3-arylpropanols.' The salr taininga traceof HrO and solid KOH ro fi a solid-liquid phase-transfer process.

ArcHO+ I +,

60- tvl

I

L. Shi, W. Wang, and Y.-2. Huang, Tetrahcd

p-Hydroxyethyltriphenylarsoniumbromide

H-

difluoin the presenceof BuoNFor tris(diethylamino)sulfonium C6H5(CH3)rSiH, particularly polar HMPT. solvents, rotrimethylsilicate(TASF, 13, 336) in aprotic The actualreagentmay well be a hexavalentfluorosilicateinvolvingHMPT. CsF and KF are far lesseffectivethan BurNF.With propercontrolof all the parameters, is alsopossible, nearquantitativeyieldscan be achieved,and high stereoselectivity as in the casewith methvlcvclohexanone.

OH

\ \sitcuH,), rHl 2 94Vo ee) r;O. DMAP(957o) 10o%)

I

160

c^H. \ "- s i"( c 6 H 5 ) 2 cll' ti

o

OH

CH, BuaNF, HMPr

&""'

OAc

./-'r,.CHt t l

+ l

+

I

\-, J

' | :: 2 rn 94Voee, ProbablYbecause I :frrrangementof the acetateof 2 sith retentionof configuration 111..1 (1989). P- .- I C.S.Chem.Comm.,89 r

!r

This reductionis and-selective in the reductionof a-oxy and a-amino ketones. for metal hydridereagentsand for hydrosilanes This contrastswith syn-selectivity in trifluoroaceticacid.

I:o. A. Hirao, and S. Nakahama' c6H5(cH3)2siH

?

C^H.CCHCH. I

tr"ift e)%

OAc l:.: reactionof H2O2Q\Vo,FMC) D:: r::. a dimethYl acetal (1) into a ; - .':cd but which for convenience ..'rall vield. The same conditions F 131; rnd trityl ethers. '.t-l " "1

,,)rllI

o

OH

..",1oo'o.1..,n^roo' CH,

o H o o H o : i l l l l 'N(c2H5), + cuHft c^H^-N(c,H5),- - -

o

i l l l c.HffN(C2H5)2

'

OH

CH,

I

"u\ /

76:24 94:6

c6H5(cq)rsiH 999o (C6H5)2CH3SiH 8l4a

98%

|

|

CH,

CH,

>99:1

(1988). M. FujilaandT. Hiyama , J. Or9.,53,5405,.5415 s(cH3h> RCHO 80%

2

with o .j-...uo in all manipulations Letters,29,56@ b:: ':. Jr.. Tetrahedron

p-Hydroxyethyltriphenylarsonium bromide, [(C.H').AsCH,CH,OH]Br (1). The at 110'. and BTCHzCH2OH saltis preparedin 697oyield by reactionof (CoH5)3As 2,3-Epoxy-3-arylpropanols.tThe salt reactswith aryl aldehydesin THF conraininga traceof HrO and solid KOH to form theseepoxidesin 60-85Voyield via process. a solid-liquid phase-transfer ArCHO * 1

;*;-

ACH-CHCHTOH

'o'

(ElZ = 74-91:26-9)

;,. :Juction can be effectedwith hY' td

CH,

: . : r n e ss u c h a s ( C 6 H 5 ) 2 S i Ha 2n d

Leuers,29,5295(1988). L. Shi, W. Wang,and Y.-2. Huang, Tetrahedron

170

Hydroxylamine-O-su[onic acid

Hydroxylamine hydrochloride. Pyridine synthesis.t Dihydropyrans (1), formed by cycloaddition of aryl enoneswith vinyl ethers(12,561),can serveas protected1,5-dicarbonylcompounds pyridines(2). and react with hydroxylamine(2 equiv.) to form 2,4-disubstituted CuHr... C:O CHOC"H< I , il i l l \ CHt I CuH,

o i i F ' 1"fi-tHlc-cH H2NosqH

L NOSO

I F.Lucchesini, N. Picci,M. Pocci,A. De Mun yb(fodL cH^cL

CuH, I

(R)-3-Hydroxybutyricacid (1), 14.l7E. Amination.t The reactionof the di butanoicacid,with di-t-butylazodicarbor 3 in high diastereomericexcess.The san

8l7o I NH2OH,HCI A ovaallj

(CH,)"C.H.

CuHr-..2N\

i l l \/

(l

t " " '

?^9

| cn.Mo

|

-

BocN=NBc

es'tc

o' I

cHa

I C.H,

Bc.

7

Q At leastone aryl groupin the enoneis essential.The reactionprovidesthe skeleton of streptonigrinoids(equationI).

H

O

O

H

."gocH3-!g,."4 BG:

I

butanoate(4) provides5 in 58Vochemica tection and hydrogenationof 5 providest

I J. P. Genet, S. Juge, and S. Mallart, Tetratx.

ocH3 ' M. A. Ciufofini (1988). andN. E. Byrne,,/.C.S.Chem.Comm.,1230 Hydroxylamine-O-sulfonicacid, H2NOSO1H. canbe preparedby reactionof c-acetylenic Isothiazoles.r Theseheterocycles acid and then with sodium aldehydesor ketoneswith hydroxylamine-O-sulfonic hydrosulfidein a bufferedaqueoussolution.

(R)-3-Hydroxybutyricacid

of aryl en, i '::nedby cycloaddition compounds 1,5-dicarbonyl pr,':ccted pyridines(2). ft rr. l.-1-disubstituted

H2Noso3H, [l;:;'l

"!.-."

t7l

+Na"Soo

#

A

' F.Lucchesini, (1989). N. Picci,M. Pocci,A. De Munno,andV. Bertini,Heterocycles,29,97

,. C-H,-*zov,oc2H5

a - l l I YI

(R)-3-Hydroxybutyricacid (1), 14,178. Amination.t The reactionof the dioxanone2, derivedfrom (R)-3-hydroxy(14,115-116)providesthe derivative butanoicacid,with di-t-butylazodicarboxylate 3 in high diastereomericexcess.The sameaminationof an alkyl (R)-3-hydroxy-

CuHt I slq" I NH2oH' Hcl A ovsall I

(EHr),C,5H5

ol At o b

C.Hr-...2N\

t

i l l

\
Imines.t This reagentcan effect dehydrogenationof secondary aminesactivatedby an aryl group or an c,B-doublebond to imines.The rate and the yield are increasedby addition of ClrRu[P(CuH.)1.and molecularsieves.In this respectiodosylbenzene differsfrom t-butyl hydroperoxide,which also effects

176

lodosylbenzene

but only in the presenceof the Ru catalyst(13' 54)' Primary this dehydrogenation, in situ to the amines ur" ulro oxidized by C6H5IO,but the imines are hydrolyzed carbonyl precursor' Ru(tr), CeHsIO,

C.HTCH:CHCH:NCoHs

C.HTCH:CHCH2NHC6H5 #'

high yield. Thesesalts,in contrastto un' phileswith the iodine (III) substituentas

Alkeny liodonium tetrafluorobomta (l saltscan undergoeliminationof iodober goes 1,5-C-H insertion (equationI). Tl

oxidationofamines.2AminescanbeoxidizedbyCoH,Iotonitriles,ketones, and lactamsas indicated'

o CH,

(r)

2C6H5IO,

n-CsHrrC-N

n-CrH,,CH'NH, #

l) Phro, BF3.O(C2lt2 2) NaBF. + E04

SnBu,

c6H5lo

o

,

4e% \,/

\-/

\J

cuHrr,o, 4s% A

n

(-,)

BF

\*Ao

i

l

H

possiblyby deIt can effect oxidativedecarboxylationof cyclic amino acids, hydrogenationto an imine. H

H

oor*>"'too" r.*uooY*Yo n"--

\J

\J

rearrangementof a p-alkyl group to pm 2. This c-eliminationof alkenyliodonium CH, c6H5l

o

BF4-

Vinyliodoniumsalts.'Reactionofvinylsilanes(2)withiodosylbenzenecat(3) in generally alyzedby BFr etherateresultsin vinyliodoniumtetrafluoroborates BF3'O(C2H5)2 C5'H5lO' /

(CH3)3c< \__J

\\

)-si1cH'),

--G-cHrcb.0'

2

rather than a carbenoid,sincethe (EF baseproduceessentiallythe sameprodu (ll)

,.",,,.fl-T:1. * tcH,i,c$No' 3 r:-eo*Jnzcuu

,a"rrraO*

CrH,r, ,Bu

Koc(cH3h

i\l*cuH, l o

BFo(E)-3 (z)-3

63% 65%

a-Oxo tiflates.s Reaction of tnmel (Tl methylsilyltrifluoromethanesulfonate :riflatesin 55-75Voyield.

Iodosylbenzene

D.< .ri the Ru catalyst(13, 54). Primary bc :rrrnesare hydrolyzedin situ to the

I'

C.H.CH:CHCH:NCeHs

177

high yield. Thesesalts,in contrastto vinylsilanes,reactvery readily with nucleophileswith the iodine (III) substituentas the leavinggroup. Alkenyliodonium tetra;fluoroborates (r4, 10-11). on treatmentwith basethese saltscan undergoeliminationof iodobenzeneto generatea carbenoidthat undergoes 1,5-C-H insertion (equationI). This eliminationcan competewith a 1,2-

or:irzedby C.HTIOto nitriles,ketones,

o

0)o\

p !

4-CjHuC-N

cH, " 1H1b,.,",, 2) NaBFd 8U7o

I

SnBu,

o p

tl

A.A'-cH, \ / ll F I

\J

--\

BF4-

t*Ao

lt-l-C6H5

Koc(cHlh --7-"

CH,

H

c: ,r;hc amino acids,possiblyby de-

6u:n

H N F) tr

\

rearrangementof a B-alkyl group to producean alkyne as in the caseof the salt 2. This ct-eliminationof alkenyliodoniumsaltsis believedto involvea free carbene

n

/

\___J

lpr . .,rn€S(2) with iodosylbenzene catDr--- :etrafluoroborates(3) in generally

:

Iti.

ilrr. -=rcH,r,c$No,

1

| VaJt,, Il o

.L6n5r ri)' BFo-

cH'\^ N(crHAo,(cH2)2N(cH,,, | *,0 41cno

\A'

Jn,

-lt-\Ao"

tl

Lithium aluminum hydride-Bis(cyclopentedienyl)nickel

cHo

CHO

Z\A

r^i.\roH

.< 2"7A \

\

)

2

)

yields obtain if 3 is Mooph at 00 to the ortho-hydroxylatedaldehyde (4). Higher 30vo Hzor' with oxidation by convertedto the tributylboronic ester followed J'C'S Chem'Comm''1350(1988)' rJ. Einhorn, J.-L.Luche,andP.Demerseman' Lithium. Reactionwithmethylenecyclopropane.|Lithiumpowderreactswithmethyl(2) asthe only product' in etherat 25otoform},4-dilithio-1-butene enecyclopropane to a methylene-1,3precursor is a This dianion is stable at 25'for 27 days;it dicarboxylicacid.

pyridyl)(1,5-cyclooctadiene)nickel. LiAIH propertiesof L suggestthat the activespo

' M . - C .C h a nK , . - M .C h e n gK, . M . H o . C . T Luh,J. Org.,53,4466(1988). r J. J. Eisch,L. E. Hallenbeck, andK. l. Han

Lithium aluminum hydride-Lithium iofl syn-l,3-Diols.r LiAlH4 alone shors hydroxyketones,but additionof Lil prorr of B-alkoxyketonesand B-alkoxy-p'-ht..

fH' c\-l-T, g o...A/--a(cH,),osiR,

4",7-.

CH. / '

;

oH

g

L

o\-A=A=4(cH2)20si

cH,_c.H.:_s rsN rf

(cH3)3siH. NTLI r.rr 12 NaBH4

J ' \666*:

R'/

(1989)' rT. Uyehara, Chem'Comm',113 N. Shida,andY. Yamamoto,,I.C.S.

lJI{,

H

\

(s)-(+)

:

(cH3)rcHcHco2H crsilcjr3h > (cE)rcHcHcH2oH

O. Meth-Cohn, C. Moore,andH. C. Taljaer C6H5CONH2

;;+

C6H5CH2NH2

ArCH=CHNO, G

ACH2CH2NHz

rA. Giannis AngewChem.lnt. Ed.'28'218(1989)' andK. Sandhoff, Lithiurn borohydride-Europium(Ill) chloride. Enantioselective reduction o! an a,p-enone.r One of the final steps in a synthesisof palytoxin, a toxin of marine soft coralscontaining115carbon atoms and 60 chiral centers,involves,in additionto the usualdeprotections,enantioselective reductionof an enone to an allylic alcohol.A mixture (1:1) is obtained with borohydrides,but lithium borohydridecombinedwith EuCl: providesan 8: I

Lithium cyclohexylisopropylamide(LCI). Thioxanthen-9-ones. This base is sq of thiosalicylamides (1) and for genenion rreatmentof l" and a benzyneprecursor(!

cocH3 SH l

B

r

mixture, with the desiredisomerbeingfavored.

cH, t "

t"'-1A11c*!""5f OH

o

cH'

resultsin thioxanthen-9-one 2 in yields a Jrmethoxy-substituted derivativesof 2 can l !\nthesiscan be appliedto synthesisof u

ll. Watanabe, M. Date,M. Tsukazaki. and! r 1989).

Lithiumcyclohexylisopropylemide(LCI) lE7

t rq:.: :\ p-eliminationwas used to effect ria6.

16. !

Lithium t-butylhydroperoxide,(CH3)3COOLi(1). The reagentis generatedln sl/r.r by reactionof BuLi or CHrLi with r-butylhydroperoxide. Epoxidation of enones,enals, a,P-ansaturated esterc.r Epoxidation of these substratesis generallyeffectedwith alkalinehydrogenperoxide,but can also be effectedwith this new reagentwith high stereoselectivity.

- )oc,H.

v'

-COOC'H.

!/

Ii

' Y. Kishi,Chemica Scripta,2T, 573(1987).

-H

6

-:

36)

\ : 1 \aOO*z

Rt/ ,

( i t e m .C o m m . , 1 1 3( 1 9 8 9 ) '

bae

.:l) 'r \aBH)

in THF is markedlY enBi: acids to optically pure amino :3duces E.-: D.: : - : rr e agent is believed to be a complex and I ::--. tuo reagents also forms LiCl

NH2

f:-;

o

A R''

tcooR'

#lAl,.r,, -> Ar"si:SiAr" .l l I 3 cl cl bnet ,

cH(cHJ2

4

Ar = CeHzCH(CH3) 2-2,4,6

r) Ar.sil'\siAr. "

mr:t\ lamine:

- o5

L-

RNCHTLi(r) S:CSLi r I R:Bu. reactswith electroPhiles rJr ,.rzedto a N-alkylbutylamine'

I H. Watanabe, K. Takeuchi, K. Nakajima, Y. Nagai, and M. Goto, Chem. Letters, 7343

( 1e88). Lithium tetraalkylcerates, RaCeLi.Thesereagentsare preparedin situ by reaction -20". of an alkyllithium(4 equiv.)with CeCl3at -78'Alkylolefins. Theseceratesconvertepoxidesinto alkylatedolefins.DME is

r".l= BuNHcH,Bu

o /

P CuHr'

\

+ Bu.CeLi '

cHr:-A.z\cH,

D M E ,- 7 8 r - 4 1 "

Mqo

C^H. t"

+

)

CHr-,,r1rz1,,,CuHt

93:7

E, lNVo I

the solventof choice,and yieldsand regioselectivity are improvedby addedTMEDA. (equation \). Nas of a sesquitetpene \sed tor slnthesis T\ris reaction

\

(r) q\\

eu'-a + t(CH)rc:cHcHPH,lnc

r

CoCl2,H2O,170'

c6H5s\

o o ll

OH (20%)

fl

ll

'c.H.icuiNrmu " l

\^Ao U

CH, lt '.

' Z . K . M . A b d E l S a m i i , M . L A l A s h m a w y , a n d J . M . M e l l o rP, .e/r. kCi .nS1., 2 5 0 9 , 2 5 1 7 , 2s23(1988\.

1989).

rl I . r litc'S€two reagents in CHzClz/tri' ni-::r:luoroacetoxy sulfides, which are t2!::,,n with allyl acetate (equation l)

)(.ll.ssc6H5

Manganesedioxide. RC=N--+ RCONHz.t Hydrationof nitrilesto amidescanbe effectedin good to high yield with MnO, on SiO,, preparedby stirring silicagel with MnSOaand KMnOodissolvedin water. Benzylicoxidationcan be a competingreaction.

l) - CHTCbEFTCOOH - - -

) MnQ/siQ

J{.r )\c + C.HTSCHTCHCH2OH I OAc

t-BuC:N

93C.

(ll%o) A:

l: OH-rr.'-- C.H5SSC6H5

c'H"'a

c6H5cH2c:N

r t-BuCoNH^

o o il- tl

-------+ C6H5CH2CONH2 + CuHrC CNH' (35Vo)

HOCH?cHCH20H -l

SC#' 11i ,rmed via an episulfoniuminterme' Drt\;.ct?t€(equationII) affordsa single

Ultrasoundactivation.2 CommercialMnO, is a weak oxidant, but can be markedlyactivatedby ultrasonicirradiationand agitationin the caseof oxidation of allvlic or benzvlicalcohols.

19t

Mercory(Il) rc€trte

o H

OH

+ )))), 17o CH3(CH2)6CH2OH-;-

,ht\

C.HTCH:CHCHO

C.HTCH:CHCH2OH ff\ 100Vo

\-Jt ,-o H,CoHA-p-r,u.or.

CH3(CHr)6CHO

+ )))),50"

Hg(OAc) THF/H,O -----i' 85qo

5Vo

v ,\

HrCOH i

I

(1988)' rK.-T. Liu, M.-H. Shih,H.-W Huang,and C.-J' Hlu,Synthesis,715 2T. Kimura, M. Fujita, and T. Ando, Chem.Letters,1387(1988)'

"Mercury. Dehydrodimefization. on excitation with a mercury vapor lamp, mercury ts a carbon convertedto an excitedstate,Hg*, which can converta c-H bond into which in dehydrodimerization, result can radicaland a hydrogenatom.This process because useful synthetically been not hasbeenknown for sometime, but whichhas of low yieldswhen carriedout in solution.Brown and Crabtree'haveshownthat this reactioncan be syntheticallyusefulwhen carried out in the vapor phase,in which the reactionis much faster than in a liquid phase,and in which very high selectivitiesare attainable.SecondaryC-H bondsare cleavedmore readily than primary ones,and tertiary c-H bondsare cleavedthe most readily.Isobutaneis is This dehydrodimerization dimerizedexclusivelyto 2,2,3,3-tetramethylbutane. is also also applicableto alcohols,ethers,and silanes.Cross-dehydrodimerization possible,and is a usefulsyntheticreaction.

O

* +cH,oH

O-O.

O*'

ra \/

HrCOH 4

slow reductionof 2 in a basicmedium is a mixture of two products that undergo precursorsto modifiedprostaglandins.' Oxidation of cyclic t-amines.2 Hg(t acid (EDTA) is the cla aminetetraacetic (1, amines 648).This reactioncan be usc

+HocH2cH,oH

O*-u:$* (1989)' I S. H. BrownandR. H. Crabtree, Am. ioc.,111,2935,2946

H8(OA.bED clhq 9tt

f", \*/

f"' o'o \*Ao

l

OH Mercury(Il) acetate. Hydroxymercuration. Reaction of the iridoid glucoside aucubin (1) with Hg(OAc), results in exclusiveattack of the enol ether double bond to give 2. Demercurationwith NaBHoin the usualway affordsisoeucommiol(3). However

"'cH,ou.

l

OH

G Carnevale,E. Davini, C. Iavarone.and ( E Wenkertand E. C. Angell, Syn. Comn .

Memry(II)

OH C.il.CH:CHCHO

,l-r, \

OH

Hg(OAc)2 THF/H,O

-----------'

'../o

85q.

\--1t ,.-o H,CoHA-u-r,u.or.

I{ .CHO :

I

OH I

f""-cu,ou \;

/

3

7

I l) NaoH 7870| 2) NaBH4 | 3) HCr

i .1s 5 .( 1 9 8 8 ) . t u r . , : t l t e s7 : : . - (1 9 8 8 ) .

o^ :

i

r-1

(r

6\

i

o^ {r

\/"'cH,oH

,

* F1

6L

+,r }rcH,ou

H2COH

H2COH

4

5

slow reductionof 2 in a basicmedium is attendedby epimerizationat Coto give a mixture of two productsthat undergo acid-catalyzedcyclizationto 4 and 5, precursorsto modifiedprostaglandins.l Oxidation of cyclic t-amines.2 Hg(OAc), in combinationwith ethylenediaminetetraacetic acid (EDTA) is the classicalreagentfor dehydrogenationof /amines(1, 648).This reactioncan be usedto convertcyclicl-aminesto lactams.

,.'-,.u.CHrOH + HOCHTCHTOH

EDTA Hg(OAc)2, cK2ctz > 93%

CH, - ('llo

fr' .

. : i.

:9{6 (1989).

f",

r

l l - o'o - ' l l \*Ao

\*/

t

OH rr..:,,rrlglucosideaucubin(1) with r:: ,. ether doublebond to give2. (3). However I .:: ,rrl\ isoeucommiol

.CH.OH

HrCOH

O-p-gluc

I

h .r ntcrcurvvapor lamp, mercuryi5 6t'rr crt a C-H bond into a carbon which rc.u.irn dehydrodimerization, ri.: .dcn svntheticallyusefulbecause ou:: .rndCrabtreerhaveshownthat 1 ..:::r.d out in the vapor Phase'in q:- .r rhase.and in which very high x.-.:. .rrcileavedmore readilythan Grr:.1thc mostreadily.Isobutaneis is u:,-- This dehydrodimerization '..-dehydrodimerization is also r t :

NaBH4 cHcll/cHl0H -i------:-----+' 85qa

acetrte

l

OH

E. Davini,C. Iavarone,and C. Trogolo,J. Org.,53,5343(1988) G Carnevale, E Wenkertand E. C. Angell,Syn. Comm.,19,1331(1988).

zffi

MersrY(II)sulfrte

Mercury(Il) chloride. treated with Cyifizatfon of 8,e-unsaturatedamines' Theseamines(1) ' when trans-2'5-disubstiHgCl, or Hg(oAc),, can cyclizepredominantlyto either cis-ot predominatesin t,itea pyrroiiaines(2), dependingon the solvent'The cls-isomer reactionswhenTHForCHClristhesolvent'whereasuseofTHF-HrO(1:1) yield in some providesmostly trans-2,The presenceof water also improvesthe reactions. \ ' : C H . +-

/

4-,1

C.Hi

\H

I

CH, I THF THF/HrO

l) Hgcl2 2)NaBH4

fl

/

cuu,\/"'cu, I

Methanesulfonicanhydride. F riedel-C rafts methanesulfonyla tiot -' with methanesulfonylchloride, but this n halo- or nitroarenes.Reasonablygood 1'r nesulfonylanhydrideand a catalyticamou CI

-ff +(CHrSOr)rO

\

* cuufl^cu, I

CH,

CH,

trans-2 36Vo 64Vo

cis-2 10:90 8 7 :1 3

S. Sato,andl. ltotr.( M. Ono.Y. Nakamura,

(1988)' I M. Tokuda,Y. Yamada, Chem'Letters,1289 andH' Suginome, Mercury(Il) sulfate. or elim' Hydration or elimination of glycats' Glycalscan undergo hydration acid.' acetic ination when treated with Hgso4 in dilute sulfuric acid or aqueous (2)'' This However,o-glucalL is convertedonly into the (1,2-dihydroxyethylxuran Thus 2 can be convefied producthasbeenusedfor a short synthesisof L-hexoses. is convertedinto product This (Mitsunobu). inversion with 3 io the monobenzoate

"€>Bqk""fPObG 3

2, ao+38"

Brzin cHroH f

nzoHp/\o?oH

c-Methoxyallene. Cyclopentannelation(U, 310). Thrs methoxyallene,which.failsto undergoc1 ditions. Actually, the reagent is (methor etherscan be used,but all musthavea dcg cation.t

M. A. Tius.J.-B.Ousset. D. P.Astrab.A H 30,923(1989).

B-Methoxydiisopinocampheylbonnc( I ). I syn-p-M ethoxyhomoallyI alcohok.t - 78'of lithiatedallyl methyletherwith l. aldehydesto providesyn-B-methoxyhom CH. I ' .A,...)rnOCH,

l\*l \l-l I

o 4

l-glucosc the l-hexenulose 4, a known precursor to several L-hexoses including and L-galactose. rF. Gonzalez,S. Lesage,and A' S. Perlin,CarbohydrateRes',A'267 (1975)' 2 F. M. Hauser, S. R. Ellenberger,and w. P. Ellenberget,TeftahedronLetters,29' 4939 ( 1988).

+ CHr:CHCH:OC}q

B-Methoxydiisopinocampheylborane

T': !-e amines(L), when treatedwith llr :,,crther cis-or trans-2,5-disubstire:r: The cis-isomerpredominatesin ; 6 i . * h e r e a su s e o f T H F - H r O ( 1 : 1 ) li(: .:i.o imProvesthe Yieldin some

Methanesulfonicanhydride. Friedel-Crafts methanesulfonylation.r This reaction is commonly conducted with methanesulfonylchloride, but this reagentgivespoor yields in the caseof halo- or nitroarenes.Reasonablygood yields can be obtainedby use of methanesulfonvlanhvdrideand a catalvticamountof acid. CI l

)

r"

+

cH,

'

-

1 T-cgt -

cuHi \'

/

CH,

uI & &

cis-2 10:90 87:13

t:2

cr-Methoxyallene. Cyclopentannelation (l2, 310). This reactionwas mistakenlyascribedto amethoxyallene,which fails to undergocyclopentannelation under the cited conditions. Actually, the reagentis (methoxymethoxy)allene. A few other allenic etherscan be used,but all must havea departinggroupcapableof forminga stable cation.t M. A. Tius,J.-B.Ousset, D. P.Astrab,A. H. Fauq,andS. Trehan,Tetrahedron Letters, 30,923(1989). (1). Preparation.I B-Methoxydiisopinocampheylborane syn-p-Methoxyhomoallyl alcohols.z The reagent2, preparedby reaction at - 78'of lithiatedallyl methyletherwith 1, derivedfrom ( + )-a-pinene,reactswith aldehydesto providesyn-B-methoxyhomoallyl alcohols(3) in 887oee.

a.HrcooH, RC6H')l

g e2qo

{ 3

F

inorron Inrz

BzoH,c/\olou

in,

#...rtocH,

\1,/

scc-BuLi -"" + CH,:CHCH2OCH3 ' tHr $..

Li-

\l./

o 4 L-hexosesincluding L-glucosc

,r-rr* | .."o J OH

t

b ...:.rrc Res.,42,267(1975)' [:. :1'crser. TetrahedronLeuers,29, 4939

R-

t ocH3

-OCHr

,,t-

t

I x'irr.tl

n Y

'M. Ono,Y. Nakamura, (1988). S. Sato,andI. Itoh,Chem.Letters,395

i1r..,.. can undergo hydration or elim!-.:.-nc acid or aqueous acetic acid'l b< . l-ttihydroxyethyl)furan (2)'' This o: . :rc\oses. Thus 2 can be converted u:r' ^r r This product is converted into

rll

?

so2cH3

'?r. : .:i.rs. 1289(1988).

\ -,

/\ ll \?

CI

CI l .s-(^-H 1Mo Ln3)ern' rw'> $4sotc"' I + (cH,so.),o ll | 8500 \?

I

}i

201

cH. '

3 (88-907oee)

_'

oa",

2U2

MelhorY(PhenYtlhb)mettrne

OH

1H. C. Brown and B' Singaram,I' Org',49' 945 (1984)' 2 H. C. Brown, P. K. Jadhav,and K' S' Bhat, Am' Soc', 110' 1535(1988)'

*"ro "*"4r.*lt', -\

T

[(Methoxydimethylsilyl)(trimethylsilylmethy[lithium,

(CE)r?i-CHSi(CH3L (1) 3 + (C.H'),P:CHCOOqIL

ocH3 Thereagentispreparedfromthecorrespondingsilanewitht-butyllithium' ketonesprovides vinylsivinylsilanes,. The reaction of 1 with aldehydesor reaction' lanesvia a Peterson-type Rt-.

_?8. _ * I -3*

Rt-..

*rrc:""t(cH'), (ElZ= 2-3:r)

*r-":o

rT. F. BatesandR. D. Thomas, J' Org',54'1784(1989)' (E,Z).l.Methoxy'2'methyl'3'(himethylsilyloxy)-1'3'pentadiene' ImProved PreParationt: HCo2c2HlNrH

-#.r"''\ll c,4Cc,H, ?

13' 180-181'

3

of the double bond (t-BuOK) prorrd compound(4), which is convertedrnt comp roaceticacid. 1,4,7-Tricarbonll estergroup of 4 to an aldehydegrou 1,3- or 1,4-Diketones.: The to aldehrd t phenylthio)methyllithium alyzedby a Lewis acid to form P-nr migrationof the phenylthiogroup. 1 as shownin thc 1.3-or 1.4-diketones l) BoLr

OH

z),r"ct rrcxl(co(cH2),oH ----i---*l ll ll I \AcotcH2)4oH

stco

'M. Yamaguchi, (1988). Letters,29,5671 T. Takata,andT. Endo,Tetrahedron (MAD, 1), 13, 203. Methylaluminumbis(2,6-di-r-butyl-4-methylphenoxide) Conjugatereduction of enones.r This reduction can be effectedwith 2 equiv. of Li(Bu)(r-Bu)rAlH (2) and of MAD. The choiceof solventscan affectthe selectivity. Stericallyhinderedketonesundergo1,4-reductionvery readily.

|,.2,

,\

o

85Vo yield by reactionof c,B-enalswith 1 in pyridine catalyzedby dimethylaminopyridine.

\acoocH3

+

€ther

","YA"

-1%

/') CH,

",c;,A.Aocn, * 1 -ry:PY1lIlCH, (E)-2

r n , \ n c ( l ) a f f o r d sa 3 : l m i x t u r eo f

CH,

QH,

,

CHt

+

/ tii :li

rJ. Rodriguez (1988). Synthesis,534 andB. Waegell, Methyl (R)-3-hydroxybutyrate' (1). Chiral S-lactams.t The reactionof l with (CrH,)rZnin THF providesa, which providesb, which reactswith the on treatmentwith lithium hexamethyldisilazane (3), an intermediateto thienamycin. imine 2 to provide a singlecrs-azetidinone

3:1o OH

r^i \, r

submitted(1988).

t cH-!coocH3 (R>r

LNtSi(CHrhl, ---:+

,zcHt CH,)2NCH2COn-O"

cil.

C-CCeHs

|n..:.ct\lationunder neutral 3 (r'R,3R,45) b .zCHt rClt r.\CHTCON.

-ococH3

|

-o"

t

I + CHTCOOH

|

. r\!

)

I N. OguniandY. Ohkawa, (1988). Chem.Comm.,1376 "/.C.S. (L). Synthesis.' CH:CH:C:NAr Methylketeneimines, 12+2lCycloaddition with aldehydes;2-iminooxetanes.2 Lewis acids are not usefulfor this cycloaddition,but tracesof lanthanideshift reagents,Yt(fod)3,Yt(hfc)r' or Eu(hfc)3are very efficient catalystsfor cycloaddition to a mixture of (cr.s)-and (2) in the caseof both aliphaticand aromaticaldehydes' (trans)-2-iminooxetanes

208

Methyl (E)4uethoxy-2.oxo.&buteno&te

TheZlE ratio is largelyindependentof the lanthanidecatalystand of the aldehyde, except in the case of methylketeneN-benzylimine.Dimethylketeneiminesalso

1+RCH:O#

c",

c", . /*

,L;

R''

:

-1:l

(z)-2

ot l

cH,o&o , I

,aoC'Ht

+ l l CHt

ocH3 I

o

(E)-2

undergothis cycloadditioninT0-90Vo yieldeventhougha quaternarycarboncenter is formed at C, of the adduct. 'Typicalpreparation: A. Battaglia, A. Dondoni,andP.Giorgianni,J. Or9.,47,3998(1982). 2G. Barbaro,A. Battaglia, andP.Giorgianni, ibid,53,5501(1988). Methyllithium. Decarboxylation of carboxylic acids.t Reaction of methyllithium with nonenolizablea-phenyl-or c-phenythiocarboxylicacidssuchas L in HMPT resultsin a Haller-Bauer type fragmentationwith lossof CO2.The intermediatecarbanion can be trappedby variouselectrophiles. COOH I

l) cH3Li, HMPT

CH3(CHr)5-i-cH3 2!9:----, 83qo I sc6H5

CH3(CH2)5qHCH3 -l

to{

"""

_ /*

^R " l _ J

ll rn 5'

ocHs e n d o - 2( 6 : l \

? (ot" r+ll \oo.

tr*oucHro\uY rr ; )v/o Y

I octt

endo-4(>15'lt W. Trowitzsch,Z. Naturforsch.8..328. l(| : D. L. Bogerand K. D. Robarge.l. Org -S

sc6H5

si(cH3)l

l) cH3Li.HMP.

2)crs(cH3)3> cH3(cHt5-c-cH3 r

(l pMethylphenylsulfonyldiazomethrnc (l). Preparation.' sec-Homoallylic alcohols.z Reactx vides the sulfone 3, the anion of which ,

sc6H5 'J. P.GildayandL. A. Paquette, (1988). Leuers,29,4505 Tetrahedron

o il

Methyl (E)-4-methoxy-2-oxo-3-butenoate, CH3O2CC-CH:CHOCH: (1). Preparation.t Diels-Alder reactions; carbohydrates.' This B,^y-unsaturateda-keto ester undergoesDiels-Alder reactionswith electron-richdienophilesto provide proreactionof 1 with ethyl vinyl tectedsugars.The thermal and pressure-promoted ketone providesthe endo-adduct2, which can be convertedin two stepsinto the 3. The samereactionof I with (Z)-\-acetoxy-2-benzy' ethyl p-mannopyranoside and givesthe endo-adduct4, which can loxyethyleneis even morc endo-selective, be convertedinto a derivativeof benzylDL-mannopyranoside.

OH

oA--cH' t.

I, HBFd + 13qa

ocHl I

nnl

d

R'

3

2, R = (CH2)2C6H5 R'= CH:

u r ti : ." t R

s

p-Methylphenylsulfonyldiazomethane

n:hanidecatalystandof the aldehyde, also z\.rmrne.Dimethylketeneimines a\R )

4",

o rlkbt

a"ro\o \

,

/* + l l ..1-O -l:1 R''

I

8",

+

ocH3

o

(E)-2

|

-'*-

,/.OC2H'

l. Org.,47,3998(1982). r.:: i' (iiorgianni, u 5-t 5501(1988).

R;.:Jrrorof methyllithiumwith nonrfi- ,.:dssuchas1in HMPT resultsin r : ( O.. The intermediatecarbanion

oc2H5

.",o lilol,f,l?":;"

*r\7ot'",

rc- :hougha quaternary carboncenter

ocH3 or--3

e n d o - 2( 6 : l )

l) H.. PdC, 57qo

(o"' I + ll \oo.

OBzl

,roo. cH3o --+ 5uva

zt r-ierH..

'

AqO. Pv, 689o

A ^n

) nLv

OAc Dr--5

endo-4(>45:l)

n *

I W. Trowitzsch , Z. Naturforsch.B.,328, 1068(1977). 2 D. L. Bogerand K. D. Robarge,J. Org.,53,5793(1988)

'tt,rCHJs$HCU, I

sc6H5

7 -

(tosyldiazomethane), p-CH.C.H.SO2CHN2 p-Methylphenylsulfonyldiazomethane (l). Preparation.' sec-Homoallylicalcohols.2 Reactionof a sec-allylicalcohol(2) with I providesthe sulfone3, the anion of which can be trappedby an alkyl halide to give

si(cH,). l ,II,(CHJs-!-CH, I

so2c7H?

sc6Hs .:: '

OH

19 -1505(1988).

o I

Ci: r CC-CH:CHOCH:

|

"p.\z-uHrl R' (1). Prep-

a-keto ester I::. p.1-unsaturated dienophilesto provideproJr,':-r-rch on: '::J reactionof L with ethyl vinyl a: ': convertedin two stepsinto the Ir,.: ,,i I with (Z)-1-acetoxy-2-benzy4, which can hxl:::r.'r the endo-addttct rt:.,::r,rpvranoside.

^-_

-t ,

2, R = (CH2)2C6H5 R'= CH:

HBFd

r;-.

QCH2SO2CTH? r) BuLi,rHF 2)Bul | ^_-

-

n'\zCH' I R'

"\rt", " l 4

.,* | 2BuLi, '- -JrHF. HMPr

Ho-r'Bu I

I

5

Bu

R'

3

R^/

o

I R'

2r0

Methylsutrenyl Hduoronethmesufonote

4. In the presenceof HMPT the anionof 3 undergoesa [2,3]Wittigrearrangement to provide an unstablealdehyde,which is trappedby an alkyllithiumto give (E)homoallylicsecondaryalcohols(5). 1A. M. vanLeusenandJ. Strating,Org. Syn.,57,95(19'17). 2R. BrticknerandB. Peiseler, Tetrahedron Leuers,29,5233(1988).

9-2 3-Cletnaty

Methyl (Z)-3-phenylsulfonyl-2-propenoate, C'HTSCH:CHCOOCH3(1), m.p.51".

d This vinyl sulfone can be obtained in 70-85Voyield by reaction of methyl propiolate,sodiumbenzenesulfinate, andboricacid(1.5equiv.)in THFi HrO (1:1) catalyzedby BuaNHSOa.' B(oHh,

Hc-ccoocH, + cnHrSorN.JqIHq- 1

?o.

I

/ | CH-CH,

+ l

; * l l

+

AcO

o tl

OAc

(oo' o'oM\,sc2H5

9A. +

.,.\....COOCH3

/\*/COOCH3

r : r l lI

I

CH(-\/\SO2C6H5

protectedderivative (c - 3) of glucosc exclusivelybecauseof the 2-acyl sube

rF. Dasgupta andP' J' Garegg.Carboht

Methyl p-tolyl sulfoxide' 14, I l5' u,P-SulfinYl ePoxides. The'Y90Voyield with only tracesof the corresponding sulfones.'

o *#L 2-o2NC6H4SoCl + KOr+C.HTSCH,

cuH,3cH,

I L. C. Vishwakarma, O. D. Stringer. arr 2F. A. Davis,S. G. Lal, andH. D. Durr

Nitrogendioxide,NrO.. N-Nitrosation.t N-Nitroso-and warmingto lactones.A reviewof thrs concludesthat the route via nitrord lactamsproceedsin almost quanttta CHrCl2at - 10".

f

C:6

(cH,)i -" xn \ \__-/

trzv.' " tn'*n', C, I , (iH.)| " e2-tffi%

I, n -- 4-14

\

\.

\_-/ !

I Y. H. Kim and D. C. Yoon. Tetrahedron Letters.29.6453(1988).

r N. Torra,F. Urpi, andJ. Vilarrasa.fa

o

tl

(1), m.p. 722' dec. peroxide,(p -OTNC.H.SOL p-Nitrobenzenesulfonyl

I Halogenationof arenes,r Chlorinationor brominationof arenescan be ef' fectedwith (C,H.).NHCI or (CrH5)3NHBrin CH.CN or CH,CI in the presenceof p- or r??-nitrobenzenesulfonyl peroxide.The effectivereagentsevidentlyaresulfonyl hvpohalites. C6H,CH3+(CrHr),NHCtf:#j-

+ (CrH,),NHBr C6H5OCH3 --

CIC6H4CH3 (plo= 58:42) p-BrCuHoOCH, (P/o= 100:0)

I M. Yoshida, (1988). andN. Kamigata, Chem.Letters,2017 H. Mochizuki, 13, 23. C.HsSOzN:CHCoHTNOT-p, N-(p-Nitrobenzylidene)benzenesulfonamide, Preparation.t Catalytic oxidation of R$ to R6S=O.' This sulfonamidecan function as a catalystfor oxidation of sulfidesselectivelyto sulfoxidesby Oxone@(potassium peroxymonosulfate). The net efiectinvolvestransferof oxygenfrom an N-sulfonyloxaziridineto the sulfide.This catalyticsystemis useful becausesulfonesare formed if at all only in traces.

l-Nitro-2-(phenylthio)ethylenc. C-H. Indolizines.2 The reagentreact of N(C:H.). to give the indolLrne dc formed.

R:.,A*-R

i l l Br-\*2 I

cH2cooc2H5

c

2,R=H,CH:

N. Ono,A. Kamimura, andA. Ka1..l : Y. Tominaga, Y. Ichihara, andA. Horr

( 1S,2R).Norephedrine, C6H.CH(OH Enantioselectivealkylation oI q, amountof the N,N-dibutylderiratirc of esterssuchas 3 or 4 to form (SH cvclizeto opticallyactivealkvl-sublt

(1S,2R)-Norephedrine 219 a ; rhosphodiesterbond to the 5'-

l.:.. ( him. Scand.8,,37, 857(1983). c r ( : . \ . v a n d e r M a r e la, n d J .H . v a n

r bypotassium superoxide s ,'rrdrzed ; .r.ndesto sulfoxides at -25" in

rL. C. Vishwakarma, O. D. Stringer,and F. A. Davis,Org. 9yn.,66,203(1987). ' F. A. Davis,S. G. Lal, and H. D. Durst,"/. Org.,53,5004(1988).

Nitrogendioxide,NrOr. N-Nitrosation.t N-Nitroso-and N-nitrolactamsare known to decomposeon warmingto lactones.A reviewof this methodfor conversionof lactamsto lactones concludesthat the route via nitrosolactamsis preferablebecausenitrosationof lactamsproceedsin almost quantitativeyield with NrO, and sodium acetatein CH2CI2at - 10".

ini.ulfones.'

o - \ ' i r l l -----_ --------rc6H5scH3

,€F"#*F,C::" c.t A

ft:o

-4(CH")1s-Bs% U

I, n = 4-14

|

+N=N+O

3

t ^ - : < .(r1 9 8 8 ) .

I N. Torra,F. Urpi,andJ. Vilarrasa, Tetrahedron,45. U63(1989). li. 1l l. m.p. 122o dec.

:: slnation of arenescan be ef{ ( \ (rr CH:CI2in the presenceof evidentlyaresulfonyl :t:r: r-.dgents

I l-Nitro-2-(phenylthio)ethylene, C.H.SCH:CHNO: (1). Preparation. Indolizines.' The reagentreactswith the pyridiniumsalts(2) in the presence of N(C.H.). to give the indolizinederivatives3 and 4. When R : CH., 4 is not formed.

R:-\zR L

-

clcuH.cH, : ' = 58:42) I-BTCoH.OCH: ,. o = 100:0)

t: ,.:::r'r-t. 2017(1988).

i l l B.\r{ry' cH2cooc2H5 2,R=H,CHr

c2H5o2c 4 (0-397o)

L N .O n o ,A . K a m i m u ra n, dA . K a j i ,J . O r g . , 5 1 , 2 1 3( 199 8 6 ) . :Y. Tominaga, Y. Ichihara, andA. Hosomi, (1988). Heterocycles,27,2345

.ll SO,N:CHC6HaNO1p, 13, 23. h:. -ulionamidecan functionas a su.:.,rrdesby Oxone@(potassium n-t.:: tri oxygenfrom an N-sultonc: t. useful becausesulfones are

(eryrhro) (1) . (l.S,2R)-Norepheilrine,C$,CH(OH)CH(CH)NH. Enantioselectivealkylation of a-formyl esters,t In the presenceof a catalytic amountof the N,N-dibutylderivative(2) of 1, dialkylzincsadd to the formyl group esters.Theseesters of esterssuch as 3 or 4 to form (S)-4-or -5-hydroxyalkanoic lactones. cyclizeto opticallyactivealkyl-substituted

(1S,2R)-NorePhedrine

o il

t" # nilcur;pooc2H5 + (cH3)2

H-c(cHr)rcooc2H5 HO

CH,

,rofo"-

Organoaluminumreagents. Review.r Use of these reagen (130references).

ff cu,z\oAo

1 K. Maruoka and H. Yamamolo. Terrc

S, 907o ee

o t" # + (crH5)2 HJ(cnr),coocH, 4

#

crg,AoAo S, 887oee

and K. Ebihara,chem'Letters'843(1988)' I K. Soai,S. Yokoyama,T. Hayasaka,

chiral. Organoboranes, of Synthesis Purc enantiortcrtobtainedfrom ( - F organoboranes opticallypure amines,halides.hrdt aldehydes,a-chiralacids.esters.nt ' H. C. BrownandB. Singaram. .{i(-'

OrganoceriumcomPounds. RCeClr. The reagents.Prepa than RLi in 1,2-additionto cartro (I ) alkoxypropionoyl-1,3-dithiane hen obtainseven'* tereoselectivity

R'e il-

CH.YS/ il

o I, Rr= SiMez-t-Bu cHrLi CH3CeCl,

{ 6

T. Imamoto,T. Kusumoto.\' Tarl J. Org.,49' 39Ol(lgttrt Yokoyama, rT. Sato,R. Kato, K. GokYu.and T

OrganocopPer reagents. Role of BF3'O(CrIItlt in rtr.' the beneficial effect of BF. ethen activation. Lipschutz et a/.' conclu Spectroscopicstudies of the efiect

HC CH.)rcooc2Hs \

O

,1i

CH, I

Organoaluminumreagents. Review,t Use of these reasentsin svnthesissince 1984has been reviewed (130references).

\,,4

I K. MaruokaandH. Yamamoto, Tetrahedron. 44.5001(1988).

9^; ee

I

4

|

c,u,

|

oAo S, 887oee

r:

, , : r ' f n .L e t t e r s ,8 4 3 ( 1 9 8 8 ) .

Organoboranes, chiral. Synthesis of purc enantiomers. Brown and Singaramrhavereviewedthe chiral organoboranes obtainedfrom ( + )- and ( - )-pineneand their usefor synthesisof opticallypure amines,halides,hydrocarbons, lithiumalkylborohydrides, ketones, aldehydes, a-chiralacids,esters,nitriles,alkynes,and alkenes. 1H. C. BrownandB. Singaram, (1988). Acct.Chem.Res.,21,287 Organoceriumcompounds. RCeClr. The reagents,preparedin situfromRLi + CeCl.,raremore reactive than RLi in 1,2-additionto carbonylgroups.An exampleis the reactionwith 2(1), preparedfrom methyl(S)-lactate.' The alkoxypropionoyl-1,3-dithianes diastereoselectivity obtainsevenwhen the protectinggroup is incapableof chelation.

Rro $a i I

*'"

+

l---+

anti-2

CH,YS/ o 2 (syn)

l, Rt= SiMez-t-Bu cH3Li CH.CeCl,

407o l ll"/o

80:20 94:6

'T. Imamoto, andM. T. Kusumoto, Y. Tawarayama, Y. Sugiura, T. Mita,Y. Hatanaka, Y o k o y a ml a . ,O r g . , 4 9 , 3 9 0( 149 8 4 ) . I T. Sato,R. Kato,K. Gokyu,andT. Fujisawa, (1988). Tetrahedron Letters,29,3955 Organocopperreagents. Role of BF;O(CrIIr), in reactionsof R2CuLi.t It is generallyacceptedthat the beneficialeffect of BF. etherateon cupratereactionsresultsfrom substrate activation.Lipschutzet al.l concludethat BF. etheratealso modifiesthe cuprate. studiesof the effectof BF. etherateon (CHj)rCuLi indicatethat the Spectroscopic 221

2?f2

OrganocoPPerreagenrs

into a mixture of four components: Lewis acid converts the homocuprate is more cH3Li'BF ' and BF'' In general'(cH')'cu'Li fttH,lcrr-il2, (cH.):curli, then 2 CuI' 2 + CH'Li 3 preformedfrom reactivethan (CHJ:Cut-i, unA can be about to etherate BF' with (CH:):CuLi BF.. It can alsoU" g"nt'uttO by warming L0' beforeaddition of the substrate' more thermallystableand alsomore RCuIS(CH)2. Variousalkylcoppersare reactiveindimethylsulfidethaninetherortetrahydrofuran.Thissolventcan in alkylationof acid chlorides'l improveyieldsin .oniugut" additionsand reductionof the Cul-triCoupling with ROil: The lithium naphthalenide activeCu(0)' This speciesreactswith phenylphosphln..ompt"x resultsin a highly to reagentthat reactswith acid chlorides alkyl bromidesto give an alkylcopper nitriles, esters' as such functionalgroups furnish ketones.This synthesi,tot"iut", canbe a competingreactionwhen Homocoupring haride,and evensomeepoxides. than bromidesand with phosphinesother alkyl iodidesare used in place of the

o cl(CH2LMTB' CUB!.S(CHIl BF,.O(C,H 977o) from 4

,(' '

o sff-'

I

Vinyllithiums (cf. 13, t421.. A couplingof vinyl and aryl triflaresrrri formula (R,Sn),Cu(CN)Li,.prepared -50o to -60". The higher-order cup - 20oto providea vinyltin intermedia providesa vinyltin, with brominea rir

Reaction with p-propiolactones.t Theselactonesare cleavedto 3-substituted propionicacidsby a numberof organocopperreagentsincludingRrCuMgX, R.CuLi, RzCu(CN)Liz,RCu'Bu,P.The reactioninvolvesselectivecleavageof the B-carbonoxygenbond. \

R2CuLi,

oH

CH.

c2H5-_z

Pentvl

(Z,E> 977o)

osiR3oH BzlO_...LzL,,1

(cHJ3Si

(E)-4

Cr,t\:r/

: CH,

BF3.qC2H5b,

50% frcm I

(z,z > 97%)

osiR3oH nzfo-.r\_,i_,{

orf ,\

t

\./

I) @u3sn)2CffrL2 2) ArOAc - l 91%

l

/ I \

Benzylic organocopper rcatcrc,

(

Zn@rcH2cH2Br\

I

R(cH,),cooH T

(111, Polypropionate1,3-diols.e The method for synthesisof syn-1,3-polyols 139)of the polyacetatetype has beenextendedto polypropionatesmerely by use of an (E)- or (Z)-propenylcuprate,(CH.CH:CH),Cu(CN)Li (1), in place of a vinvlcuorate.

1r)crH,iHBrd.$-.--

cJ..r

(R = H, CH3)

Theseorganocopperreagents(equan hydes,acidchlorides,enones,allvlicb

Organocopperreagents BF, r::*

o Bzlo ..'\ r# H...

,--1 / (CH3)3Si |

o

OSiR3

l) vo(&rch

H Bzlo-rzL,.1r.CH,

2"-F

Bzlo-r''L''{i'

c2H5-z

3

osiR3 oH .o BzlO...,,,L,,1-.{j.C\

E

osiR3oH BzlO-r,,1r\-.,1r,CH, CH,

CH,

L.

t - :...

t:\:a

.

er* | tcq=cxl,corcnylq

Heptyl

(Z'E > 97Vo)

OH Pentvl

*

osiR3oH oH Bzlo-r2L,\-,\zCH:CHz CH, CH,

H

t ,, /:\:/

f -

r.l

urolcl-r *

OH 1...H 'Heptyl

225

.PentYl

! . I l
974o)

Vinyllithiums (cf, 13, 142).10An improved route to vinyllithiumsinvolves of the couplingof vinyl and aryl triflateswith tributyl- or trimethylstannylcuprates formula (R,Sn)zCu(CN)Li, preparedfrom LDA, R.SnH, and CuCN in THF at -50'to -60". The higher-ordercupratescouplewith vinyl and aryl triflatesat - 20'to providea vinyltinintermediate. with AgOAc Work-upof the intermediate providesa vinyltin, with bromine a vinyl bromide,or with CF.COOH an aryltin.

orf

l:,i,,:t€sarecleavedto 3-substituted !ri: :.r!\includingRrCuMgX' RrCuLi, ofthe B-carbonF. .:.rctivecleavage

,\

t

l

\-,/

1) (Bu3SnbcucNLi2 2) AgOAc ) 97qo

+ RSnBu,

B enzyI ic organocopper rcagents, CoIIsCH zCu(CN Z nB r (l).

Preparation:

cri cooH R I

Zn(BrCH2CH2Br),

(l) CTHTCHBT #* (1lZ' I i,.: .inthesisof syn-1,3-polyols use by merely lgJ :., polypropionates of a place (l), in l:( lI).cu(cN)Li,

(R = H, CH3)

R I

C.H,CFZnBT

CuCN.2LiCl,

rHF'-20' t

R I

curtrcHculcNlznnr I

Theseorganocopperreagents(equationI) react with variouselectrophiles,aldehydes,acidchlorides,enones,allylicbromides,in 85-95Voyield."

cH'

OrganocoPPer reagents

t26

Alky lbis(t-butylphosphidolcttpnata. I obtainedby reactionof RLi with [CuP(tin THF at 25ofor 4 hours,but can be usc ment (particularlyof primary halides).an a-Alkoxyorganocuptates.t5 c-Alkor shown,provide a novel synthesisof tetra

CI CH'Cu(CN)ZnBr + CHr:fllgHzBr

CH,CH'CH:CH, -+ CI

CI

t#4

+ rcHo C.H,CHrcu(cN)ZnBr

c6n5cHrc.tpr OH

tl

|

|

\,,'

t-a\ /'V'cH'cu(cN)znBr + ll ll |

?C Y

cH2cc6H5

+cuH'cocr-------+

ll

I

\./

o tl

(CN)ZnBr

.--\)-\Z'\/CH'Cu

N

8

4O

crsi(cH,)1(car) AYY) t------?l ll

q

C

A

YN

ll

Y

r

O

tH3-Li-o-

3(CH,)rCuLi+ HrO ------+ZCH.+CHrCu+ Cu

t" cH3-Li-cH3 I

asl,andapolymericmethylcopper.Thisnewreagentundergoesrapidanddiasadditionto enones. tereoselective

ll

t

l-t*i-

+ 1 6 :I

l,,Io"orlx&n, "u c.nf

c' si(cHrlr,

O*,

J

,.Li

cuH'.-/Y/\c.g. -'. H' OMOM

l- gsircH,

?

preparedfrom (CH)3SiLi Lithium bis(trimethytsilyl)cuprate'D This cuprate' in moderateto high yield' and CuCN, convertsacyl chioridis into acylsilanes traces of water' lithium Methyloxidocopperlithium (l)'t! In the presenceof tentativelyformulated dimethylcuprateis convertedinto a bright yellow reagent'

o

,OCH"OCH" - r, a.r, ' 2)crc\ -,4-(cH3)rcHCH 'SnBu,

cH(

L

2 in the presenceof TMSCI givesa srng uith TiCL at -78'cyclizesto a crs-fuse at thc can alsoshow diastereoselectivit-v nng. when comtrn c-Alkoxyorganocuprates to preferential1,4-addition c,p-enals r s .elective(45-250:1).The 1,2-addition OMOM

gu\

I

t2

+ euA'/cHo cu(cN)Li, -

j

oMov t t

B,Y

OH (r.2-d l7{

Organocopperreagents

Alkylhis(t-butylphosphido)cuprates,RCuP(t-Bu){,i.ta These cuprates are obtainedby reactionof RLi with [CuP(t-Bu)la.The cupratesare generallystable in THF at 25ofor 4 hours,but can be usedfor conjugateaddition,halidedisplacement (particularlyof primary halides),and epoxidecleavage. a-Alkoxyorganocuprates.tsct-Alkoxyorganocuprates suchas 1, preparedas shown,provide a novel synthesisof tetrahydrofurans.Thus conjugateadditionto

I \_.,.cH.cHrcH:CHz Act H}: t!

rlnur-i,

(cH3)rcHdH 'SnBu,

o tl

f

MoMo "'-- -t I

I | 2)cucN, cutcNyr-t, [cu,l,cHcHlrJ I

,OCHTOCH,

cH2cc6H5

o

ll

I

-l-

77%

H cH(cH3)2 3 (69:31) H '^

a

Yo

('\

preparedfrom (CH3),SiLi 5 . --:'r.rte. to high Yield' moderate rn Ji'.:. of water,lithium traces of p:J-r:rce formulated ; tentatively :c.rgent, Jl. I i

C H .- L i - o /

I Cu Cu I -Li-cH3 I I

l { i - -

Ticl{ CH2C12, ----{

l l +l l

w.'

CH,

I

2 in the presence of TMSCI givesa singlesilylenol ether(a), whichon treatment with TiCl. at -78'cyclizes to a crs-fusedannelatedtetrahydrofuran.The reaction can also show diastereoselectivity at the exocyclicpositionof the tetrahydrofuran ring. cr-Alkoxyorganocuprates whencombinedwith chlorotrimethylsilane alsoundergo preferential1,4-additionto c,B-enals.Of greaterinterest,the additionis syn(45-250:1).The 1,2-addition selective showsno diastereoselectivity.16 QMOM .A. r Bu- )^Cu(CN)Li,+ Br',1./CHO

cls(cHl)r

rsr, -re-io',

r:.r{cnt undergoesrapid and dias-

OMOM

OMOM

,"Ftu I

/27

*

u"\1."o Bu

OH ( 1,2-adduct, 17Vo)

syn-l (30Vo) ' r- *- 1| t2) x) cr or *o l

o

tl

to

,-cli 'c.ll.

+ 1 6 I:

MOMO CuHi

I

BuflBu (crr)

I

rrl,tanti-r

nE

Organocopper reagents

Dilithium(timethylstannyll(2-thienyllcyanocuprate, (CH.):SnCu(2-Th)CNLi, (1)r?.The cuprateis preparedby addition of CH.Li (2 equiv.) in ether to a THF solutionof [(CH).Sn], (1 equiv.) and thiophene(1 equiv.); the reagentis formed after additionof CuCN (1 equiv.). The reagenttransfersthe trimethyltin group to the B-positionof a variety of esters,includingacetylenicesters.It is generallysuperiorto the cr,$-unsaturated lower-ordercuprate[(CHJ.SnCuSC6H,]Li(10, 289).

--r. THF. ,*-

CH,

orf.

CH". \_^

E

tB.!' -r _\) _ 6:-r

/

C.Hi

o

-20'

CH,

CH,

RCU-ISi(CH)s.n This reagen agentfor 1,4-addition to enones.(Zf

cH't

CH,

CH,

Sn(CHr),

,\

."4y't U"*ooc2H5,'OdJ::'*'u' CH.

t "

(cH3)3cliocHrc-c-coocrH' .-.--> I &siocH2 CH,

r

95:5

Z-3 (65Vo)

)

2

H

l) r HMPT 2)CHll, ' > 65%

(CH:)rSna__-COOC2H5 cH,

R3SiocH2 4

(r)." rhis cucopperlli thium, (\"",.*,r, 12-Th i enyI (cyano'1 -18 ---> prate is preparedby reactionof 2-lithiothiophenewith cucN in THF at -40.. It is relatively stable, but can be convertedto higher-ordercupratesby reactionwith RLi or RMgX at - 78".Thus reactionof 1 with vinyllithiumprovides (cH,:cHx2-thienyl)cu(cN)Li,(2), whichismoreusetuIthan(cH,:gH)cu(cN)Li for cleavageof epoxidesand for conjugateadditionto enones'1"

F

,CHtOBzl

* 2 +#

CH,:CHCH,CHCH,OBzI OH

CHt

CH;

+zfi-

B. H. Lipshutz,E. L. Ellswonh.and T : S. H. Bertz and G. Dabbagh, Tetrahcd ' R. M. Wehmeyerand R. D. Rike. Icrr 'J. F. Normant, A. Alexakis,A. Ghnh. i 'J. D . B r o w n ,M . A . F o l e y ,a n d D . L C ' M. Hulce, TetrahedronLetters.t). S?y< A. Alexakisand D. Jachiet,Tetrahedra ' M. Kawashima,T. Sato,and T. Fu.;isar B. H. LipshutzandJ. C. Barron..1.Orr S. R. Gilbertson,C. A. Challener.Il E 1795(l988). S. C. Berk, P. Knochel,and M. C. p li :A. Capperucci, A. Degl'Innocenri. C t ors., 53, 3612(1988). 'E. J. Corey,F. J. Hannon,and N. \,\' I ' S. F. Martin, J. R. Fishpaugh.J. t\t por and A. H. Cowley,Am. Soc..ffO. -:J6 ' R. J. Lindermanand A. Godfrey-.rbd . ' R. J. Lindermanand J. R. McKenzr. I E. Piersand R. D. Tillyer, J. Org.. 53. I '8. H. Lipshutz,M. Koerner,and D. .{. 'B. H. Lipshutz,R. Moretti,and R. Cro : M. Bergdahl,E.-L. Lindstedt, M. :\ibso

cu,

CH:CHz

CH;

CH,

Organocopper/Zinc reagents, RCu(C )ubstituted by a chloride, ester, or enoi *ith CuCN and LiCl (2 equiv.)., Tb enones,even B,B-disubstitutedones. u r e q u a t i o nI ) . 2

Organocopper/Zincresgents

tontcupmte, (CH.),SnCu(2-Th)CNLit o: r ll Li (2 equiv.)in etherto a THF tt:'rr r I equiv.);the reagentis formed p -.:' lrr the p-positionof a variety of r ..:Jr\. It is generallysuperiorto the rlll lr9).

/29

RCU-ISi(CH)yn This reagent,when solubilizedin PBu, is an excellentreagentfor 1,4-additionto enones.(Z)-Silyl enol ethersare formed preferentially. cH3cu,Isi(cH3b "Fo#5.",,

OSi(CH.)"

CH,.

)7-ci,.n-r

t coHi

5:l

c.H; z-l

* , i i ,

o

CH, Sn(CHr),

t ll,

a\

."p

a----a,Sn(CH),

I

Sn.

r( ii

R . x--ll.

,COOCzHs H

+ E-3

95:5

Z-3 (65Va) I

cooc2H5

ll.

cH, l

(

t It lc

7

Y)%

t

rAl

l

cH|/"cH3 (translcis = 5:l)

l-t"zcooc2H5

_

osi(cH3)3

'-cu(cN)Li (l)." This cu. - - ' r r n i t h C u C Ni n T H F a t - 1 8 ' - - > . -:tcd tt'rhigher-ordercupratesby -: ,'n of I with vinyllithiumprovides -, uretuIthan(cH,:gH;6u(CN)Li . . : : r ( \ nt o e n o n e s . l ' r

r B . H . L i p s h u t z , E L. . E l l s w o r t ha, n dT . J . S i a h a a nA,m . S o c . , 1 f 1 ,1 3 5 1( 1 9 8 9 ) , r S. H. Bertz and G. Dabbagh,Tetahedron,45, 425 (1989). 'R. M. Wehmeyerand R. D. Rike, TetahedronLeuers,29,45l3(1988). 'J. F. Normant,A. Alexakis,A. Ghribi,and P. Mangeney,Tetrahedron,45, 507(1989). j J. D. Brown, M. A. Foley,and D. L. Comins,Am. Soc.,110,7445(1988). ^ M. Hulce, Tetrahedron (1988). Letters,29,5851 ' A. Alexakisand D. Jachiet,Tetrahedron,45, 381(1989). 'M. Kawashima, T. Sato,and T. Fujisawa,Tetrahedron,45, 403(1989). 'B. H. Lipshuta z n dJ . C . B a r t o n l,. O r g . , 5 3 , 4 4 9 5( 1 9 8 8 ) . "'S. R. Gilbertson,C. A. Challener,M. E. Bos, and W. D. tVulfr,Tetrahedron Letters,29, 4795(1988). " S. C. Berk, P. Knochel,and M. C. P. Yeh, J. Org..53,5739(1983). r: A. Capperucci, A. Degl'Innocenti, C. Faggi,P. Dembech,G. Seconi,and A. Ricci,,/. O r g . ,5 3 , 3 6 1 2( 1 9 8 8 ) . 13E. J. Corey,F. J. Hannon,and N. W. Boaz,Tetrahedron,45,545 (1989). 'S. F. Martin,J. R. Fishpaugh, J. M. Power,D. M. Giolando,R. A. Jones,C. M. Nunn, and A. H. Cowley,Am. Soc.,ll0,7226 (1988). 15R. J. Lindermanand A. Godfrey,ibid.,ll0,6249 (1988). 16R. J. Lindermanand J. R. McKenzie,Tetrahedron (1988). Leuers,29,3911 17E. Piersand R. D. Tillyer,.I. Org.,53,5366(1988). l'B. H. Lipshutz,M. Koerner,and D. A. Parker,Tetrahedron (1987). Leuers,2E,945 l'B. H. Lipshutz,R. Moretti,and R. Crow, Org. Syn.,submitted(1988). r"M. Bergdahl,E.-L. Lindstedt,M. Nilsson,andT. Olsson,Tetrahedron,45,535 (1989).

il :CHCHzCHCHTOBzI I

OH

{,,

Il. i ll

CH:CHz CH,

Organocopper/Zinc reagents, RCu(CN)ZnL These reagents, in which R can be substituted by a chloride, ester, or enoate group, are prepared by reaction of RZnI with CuCN and LiCl (2 equiv.).r These reagents undergo l,4-addition to o,Benones,even B,B-disubstitutedones, in high yield when activatedby BF. etherate (equation I).'

Organolithium reogents

!"'

o

ll

A

0)l

\AI

Cl(CHzLCu(CN)ZnI THF, -30'

ll

E4%

Pl"o-iH(cnrbcu(cN)z^ttI -13+r BF:'O(CzHsh' r 86%

, (cHr)4cl

CH"

t -

(cHr)rcHOPiv (cHr)4cl such as 1 can be bicyclic difluoroboron enolate In some casesan intermediate a bicyclic ketone '"uttion and converted into 'solated from the BF'-p;;;;; (equationII)'

o il

or)fi

F-..

,F

dt*

r l BFr'o(czHsh ' + rZn(cN)cu(cH)3cN82qo -n \r+-./

\,^cH3

l

CH, t .

*Htg

r

o

H

proceedsin 90-99% yield at -45" with and vinyllithiumsfail to add to 1. Howev in situ ftom the correspondingtetrasubsu addition also in high yield. The reactivc r and CH.Li, or it may be nonaggregated prc are reagents RoSn also is helpful. The of Mg with RCI in THF to form RMgCl. M agnesium2-ethory ethoxide, M glOC the activityof RL alkoxide(L) decreases be preparedin THF in the presenceof 0 ce are that someunstableorganolithiurqs supp'r be directed ortho-metallationcan (D ialkoxy methYI) I i thi um, (ROI{, n this type havebeenpreparedby lithiatio metalationof (RO),CHSnBurat I ltr' -95', but cycliconesare relativell st at this type are shownfor the lithiodiorar electrophilesto give acetals.It forms ll

o o.

,\

I''.(,

(1988)' Talbert'l' org'' 53' 2390 ,p. Knochel,M. c. P.Yeh,s. c B9'I'^il9 J' 29' 6693(1988)' "d^,,-iririn"dron Letters' dihyOrganolithium 'Generationt:"C":tt; (12' 310-311) of 1,1,2-trisubstituted in situ't A synthesis 1the to of alkyllithiums as the first step addition (2) products dronaphthalenes(3) involves The lv t'"ppi"c.w:th';n electrophile' of RLi naphthyloxazorin"r toill*"i l"quaiion I)' Addition can be convertedto tormyl-l'2-iihydronaphthalenes

(I) 2 (>100:l)

L+CuI.PBur*2

h'

yield.The derivedcopperreagentwheni by conjugateaddition. Unlike most or reactwith alkyl halides,often in high y (a-H aloalkenYl) I i th iums, |X rc n ) (t halo-f -iodo-1-trimethylsilyl-l-alkene (2) in 65-&s beredcycloalkenylsilanes groupis not essentialfor the cyclizauon crs-relationshipbetween Li and the r,> Cyclizationis alsopossiblewith (ro-b is Al. Zn, Zr, or Si' In this cyclizatio

Orgonolithiumreagents CHr

t -

PivG{H(CHz}:Cu(CN)ZnI B F " ' O ( C r H < h- ,1 3 + 0 ' 86%

{-,.c1 CH"

t -

(cH),cHoPiv (CHJ4Cl h\r{,boron enolate such as L can be J c,rnverted into a bicyclic ketone

F

F

/.8... O N NaOCHr, CHrOH _-.------:-.-1 7t%

231

proceedsin 9\-ggvo yield at -45'with n-, sec-,and r-Buli, but alryl-,benzyl-, and vinyllithiumsfail to add to 1. However,these organorithiums when generated in,situfrom the correspondingtetrasubstituted stannanewith cH.Li, undergothis addition also in high yield. The reactivespecies may be an ate complexof R.Sn and cH.Li, or it may be nonaggregated reagent.In somecasesadditionof HMpr alsois helpful.The RrSnreagentsare preparedin about 70-90voyierdby reaction of Mg with RCt in THF to form RMgcl, which is then addedto snct. in benzene. Magnesium2-ethoxyethoxide, Mg(OCHTCHTOC{Is)r. preparation.3 ., This metal alkoxide(1) decreases the activityof RLi reagentsto suchan extentthat they can be preparedin THF in the presenceof 0.5 equiu. of 1. The advantages of this fact are that someunstabreorganorithiums can begeneratedby this techiique and that directedortho-metallation can be suppressed if desired., (Dialkoxymethyr)rithium,(Ro)rcHLi.s Both cyclic and acyclicreagentsof this type have beenpreparedby lithiation of (RO),CHSC.H, _ at 95. or by rransmetalationof (Ro)rcHSnBu. at -r10". The acycricreagents decompose rapidry at -95', but cycriconesare relativelystabreat -45 to -7g". Typicalreactionsof this type are shownfor the lithiodioxanereagent 1, which reactswith a numberof electrophilesto give acetals.It forms r,2-adducts with ketonesand enonesin hieh

ci''. I Or9.,53,2390(1988). N lT seqo \,/....._r1_,a0",

HcooH "r*o , 3s%

i l - l

O.......Mn(CO)n

d";,

L. S. Liebeskind, J. R. Gasdaska, and J. S. McCallum,J. Org., 54,669(1989) P De Shongand D. R. Sidler,ibid.,53,4892(1988).

216

Organosilanes

Organoosmiumcompounds. (1). Preparation.' Dialkylnitriloosmium chromates, Ibur[N-Os&1(CrOJThesemetal chromatesare efiective catalystsfor oxygenationof primary and secondary alcohols.2Primary alcoholsare oxidizedexclusivelyto aldehydesand no estersare formed from secondaryalcohols.Primary alcoholsare oxidizedmore rapidly than secondaryones.

' M. E. JungandK. T. Hogan,Tetrahedroa It

Organotin reagents. a- A I koxya I ly I tributyI tins, Bu.SnCH undergoPd(d)-catalyzed couplingwirh A vinyl ethers(equationI).

1P.A. Shapley, T' 928(1988)' H. S. Kim, S. R. Wilson,Organometallics, ' N. Zhang,C. M. Mann,andP.A. Shapley, (1988)' Am' !oc,,110,6591

il

(I) C.HrBr + I (R= C'HJ + Organosilanes. Optically active binaphthylsilacycloheptanes. Jung and Hogan' have preparedthe opticallyactivebinaphthyliccyclicsilanes1 and 2, in which the chirality

In the presenceof BF. etherate.I ism with aryl aldehydesto form mainlv s-r.na

(lI) I i!g*+

(R)-l

Bu,SnclIrCH:CltoC (ZlE = t5: t5\

(s)-2

residesin the binaphthyl groups.These silanes(X = OCH.) can effect partial asymmetriccatalytichydrogenationof enonesand ketones.The highestenantioselectivity(35Voee)is observedwith (S)-3in an aldol reaction(equationI).

ever,thermalreactionsof I with arvl aldet vinyl ethers. l,l- D i meth oxy -3- trime thy I starr! l, tl). The reagentis preparedbr

(cH3bsioTf cH'cl'. -78'

+ C.HTCH(OCH')r-=#-

ryot"t""'*t-[( (s)-3

(179oee)

o

ocH"

i l H l

AYl-.^". t l \-/ (35Vo ee)

TMSOTf BF, Tic14

&% 27% ffi%

Organotinre&gents

237

'M. E. Jung and K. T. Hogan, Tetrahedron Leuers,29,6199(1988). t,lrCrO.)- (1). Preparation.' n e.nation of PrimarY and secciu.rrely to aldehYdesand no n .rcohols are oxidized more

Organotin reagents. a-Alkoxyallyltributyltins, Bu.SnCH(OR)CH:CH, (1).' These reagente undergo Pd(0)-catalyzed coupling with ArBr to give a mixture of (E)- and (Z)vinyl ethers (equation l).

cr 1 e:8 (1988). l l 0 " 5 9 1( 1 9 8 8 ) .

Pd(o),

(I) CuHrBr+ I (R = Crrf; -lurg and Hogant have Pre; I ;rd 2, in which the chirality

,\:

v

*5

C'HTCHTCH:CHOC2H5 (E/Z= 95:5)

In the presenceof BF. etherate,1 isomerizesto 1-alkoxyallyltins,which react with aryl aldehydesto form mainly syn-c-glycolmonoethers(equationII). How-

^.,.cHt tt-*

BFl.O(C'H.:.{, EIZ = 2.6:1

a

I

:().\C

At

By useof this simpletechniquethe enantioselectivity can be increasedas much astenfold.Thusthe eefor dihydroxylationof 1-phenylcyclohexene canbe increased from 8 to 78% in a reactionof 78 hours. ' J. S.M. Wai,I. Mark6,J. S.Svendsen, M. G. Finn,E. N. Jacobsen, andK. B. Sharpless, Am. Soc.,f11, 1123(1989). Osmiumtetroxide-Dihydroxyphenylborane, OsO.-C.H,B(OH)r. Dihydrorylation of alkenes. c6H5B(oH), is useful for capture of the diols formed on osmylationwith osoo and N-methylmorpholineN-oxide, particularly unstableor water-solublediols. osmylationwith the boranecan alsobe conducted in a nonaqueousmediumwith enhancedrates.r

-Bu n

=r*J,c$*no

o oroo,cxrlr]o

qHjB(ol{h

CH2C12

I :9 :\69 (1988). estl). r,.-i :1" Lc . 111, 366 (1989). f i - , . . i r o n L e t t e r s , 2 9 ,3 8 2 1 ( 1 9 8 8 )

r lr i r:-239). Furtherstudy'of this R\r..-r.can be markedlyimprovedby at 0'with ilr: - ,i.rlrstin acetone-water tetraethylamof addition by .,.cd rn,: | : .mat€ esters.The report suggests to provide n.:r::\\ .rsecondosmylation . ' : : r l a t i o n . I

't'l{:-8'-:}l]

O-etlr..', ' N. Iwasawa, T. Kato,andK. Narasaka, Chem.Letters,l72l(l9gg). Oxazaborolidines,chiral, 14, 239-2A. (s)'2-Hydrarymethylindoline (l)t reactswith borane.dimethylsulfideto form the oxazaborolidine2, which functions as a catalyst for reduction of ketones by

BH3.:1sH3h)fr---i."

af--

-l' 'cH2oH

\A,

H

| / .,B-o 2

, | ",o J -

Ho/

\A*4.,

tl t

R

-2H2

R toH

BH3'S(CH3)3, but whichis requiredin stoichiometricamountto achievehighoptical yields.Alkyl aryl ketonescanbe reducedin this wayin 84-93Voee to (R)-alcohols, but dialkyl ketones are reduced in only 45-ffi% ee. I I. K. Youn,S. W. Lee,andC. S. Pak,Tetrahedron (1988). Letters,29,4453

U2

2-(Oxoalkyl)triphenylattoniumbromides

Oxazolidines.chiral. 3-Arytsulfunyloxazolidines.rTheopticallyactiveoxazolidinel,preparedfrom (R)-(N-toluenesulfonyl)phenylglycinoland2-hydroxymethylenecyclohexanone'

,-CHN "\,,/ I 4

additionof metal nucleophilesto the carbonyl undergoeshighly diastereoselective the chiral auxiliaryis group. on treatmentof the adductwith 1,3-propanedithiol, 4' releasedwith formation of the dithiane(3) of the aldehyde

Deoxygenation of cyclic peroxides.t o obtainedfor the first time by deoxygenatio peroxylactones (2) obtained by photosem (1). derivatives

rI.Hoppe,D.Hoppe,C.Wolff,E'Egert,andR'Herbst'Angew'Chem'Int'Ed''7A'6'l (1989).

SCHTCORBT-(1)' 13' 137; bromides,(C6Hs)rA 2-(Oxoalkyl)triphenylarsonium t4, t70. (E)-u,p-Enones.|Thearsoniumylidesformedfromthesesaltsreactwith conditionsto form (E)-a,p-enonesinTl-99% yield phase-transfer aldehydesunder particularly useful for reactionsof unstable lequaiion I). This Wittig olefination is aldehydesbecauseof the mild conditions'

'T + R'cHo :7]:"' '- ^1* (I) l[R = cH(cH,),, n-c,H111 (1988)' rY.-2. Huang,L.-L. Shi, and S.-W.Li, Synthesis,975

o

tl tn'-ioH ll R H

ll;%. H,cV R+ ;;* T

I,R=CHroreHs

,

Y. Siitbeyaz, H. Seqen, andM. Balci,I.C.S O ' Idem,J. Org.,53,2312 (1988). W. Adam,L. Hasemann, andF. Prechtl.Aarrr

Ozone a-Hydroperoxy carbonyl compouils.r ablytoo unstableto preparedirectly.but ca morestablet-butyldimethylsilylperoxidcs.

Ozone

from irc ,'razolidine1,,PrePared dr,' r r methYlenecyclohexanone, C A

?'"'

Oxygen, singlet. Endoperoxidation. Conduritol-A (5) can be preparedlstereospecifically from cyclohexa-1,4-diene via 2 by singletoxygenation(tetraphenylporphyrine), which providesthe anti-endoperoxide 3. Reductionof the endoperoxidewith thiourea2 followed by dpketalizationgivesthe cyclohexenetetraol 5.

r&ir'o"",,, _ O GK: GX",

,\so:c,H7 HS(CHr)rSH ---:----:-:--1

't{

43

3 I n,NcsNtr,, 8o7,JcH3oH,25-.

OH ; ^

a'Yu" i l r

cllo

ll

\lon : on

a\

to the carbonyl |e:.:.nucleoPhiles ra:rcJrthiol,the chiral auxiliaryis e . . J c h v d 4e '

o

t"'>Ao" ) \ . C - H , C O R B T -( 1 ) ' 1 3 , 1 3 7 ; rncJ from these salts react with yield n r [: r-cr.B-enonesin7l-99Vo rlr u.eful for reactionsof unstable

':


u%

c.H.sCH:CH lrcH,osiR3 I OH

3 I l) Hg(OAclz,HgO,CH3OH 70% 2) NrBHl I Y

. r , ' i . 5 3 ,5 3 8 9( 1 9 8 8 ) .

gNGM rli cH. (1). f ::rr.andotherB-hydroxy sulfones ianr,.nof (S)-1is alkylated at the whichcanbemarkre,..electivity,

),-r t

^ t l cH,o^g^cH2osiRl 4

carried out by alkoxymercurationfollowed by reduction and concomitantring closure.

OH I

cn, '

+

anti-2

CH.CH:CHz 73: 2 7

' T. J. Lee,Tetrahedron (1985). Letters,4995 ' A . H . D a v i d s o n , C . D . F l o y d , C . N . L e w i s , a n d P . L . M yCe hr se,m " /..C Co. S m.m . , l 4 l 7 ( 1988).

syn-2

58:42 8 5 :1 5 i ::rrrlarto that with alkyl halides c n er . :

Phenylthiomethyl(trimethyl)silane, C.H,SCH,Si(CH,),(1), 10, 313-314. p-Hydroxyalkylphenyl sulfides.t In the presenceof BuoNF(0.1 equiv.) this silanecan effect phenylthiomethylation of aldehydesor ketonesto provide silyl ethersof B-hydroxyalkylphenylsulfidesin moderateyield. The solutionof Bu,NF in THF shouldbe dried with 5-A molecularsievesbefore use. Yields are usuallv

2U

(Phenylthio)nitromethane

improvedby useof 1 equiv. of BuoNFin the caseof aryl aldehydessubstitutedby group. an electron-withdrawing

R ing- enlarged a-ph cnyII of I (2BuLi,THF/HMPT)ri (2 equiv.)to a-phenylthioc

Bu4NF,25"

tuCHO11JIl-*4t

cHCH2SC6H5 OH

1",

CH, + CoHrS-:lrJC

C6H5!CHrSC6H5

C.H,COCHT+| --

CuH,

/'cH2sc6H5 /\ * 1- N*-,.Q,, j_o"

(.e?.:

I F. G. BordwellandJ. E. Baru I S. Kim andJ. H. Park.Chcm

IA. Hosomi,K. Ogata,K. Hoashi,S. Kohra,and Y. Tominaga,Chem.Pharm,Bull''36, 3736(1988).

Phenylthionitrile oxide (1). Generationand trappingwith an alkene:

Phosgene. cis-Oxyamination of dh tion with phosgeneand then which cyclizeson treatmen Debenzylationfollowed by-h

I c6H6' N(qH')r-

cuHrNCo c6H5scH2No2+

[cuHrSC:N-+o] + cuHrNHCxncuH, I 30soJcH3(cH2hcH=cH2

\i-9 il

-

|

c.ursA4cor6 o

2

Br

'oH

l)ctrLxaJ 2)qH'cn t{rr 7rt

crc6!r.co1H \i-? il | e1% cuH,s^}coHn r ,

This route providesa two-stepsynthesisof 3-(phenylsulfonyl)-A' -isoxazolines (3). The phenylsulfonylgroup can be displacedby variousnucleophiles.r

I J. Das,Syn.Comm.,ft. 9(}?(

I D. P.CurranandJ.-C.Chao,,I. Org.,53,5369 (1988)' (1). (Phenylthio)nitromethane,C6H5SCHTNO, Preparation': l) KoH

{

iiscuH,* NorcHrcooc ,s, 2#

|

Phosphines,chiral. H y drogenation catatyto: have been developedfor sc aminoacidprecursors,includ and the novel ligand3. in ri hasbeen usedas a Rh(I) co

phosphines

a:c trf aryl aldehydes substituted by

26

^ ,Ring-enlarged a-phenyrthiocycroarkanones.2The adducts(2) of the dianion of I (2BuLi, THF/HM'r) with cycloarkanones rearrangein the presenceof Arcl. (2 equiv.) to o-phenylthiocycloalkanones.

vcHCHrSC6H5 OH

i"'"'

CH, I

CHr+ C.HTSC:NO,-

l.H.ccHrsc6H5

85%

OH

o tl

74qo ft-scrH, ",n5cn,

I

CuH,

l H .r . C

HO _ CHNO, 2Arcr, > (,}"", CuHt t

/,cH2sc6H5

lF. G. Bordwelt andJ. E._Barrmess, J. Org.,43,3l0l(197g). I S. Kim andJ. H. park,Chem.trttru, tii flqs8i.

-oH

I,,minaga,Chem.Pharm.\uil..36.

ot l

Phosgene. cis-Oxyaminationof alkenes.t trans-1,Z-Bromohydrins . on consecutivereac_ tion with phosgeneand then benzyramine are convertedinto a bromo carbamate, which cyclizeson treatment with NaH (2 equiv.) to a cls-oxazolidinone.NDebenzylationfollowed by hydrolysisp.ouid", a crs_1,2-amino alcohol.

SC:N -rOl + CuHrNUCuuCuH,

Bzl

I t +

t H3(CH2)3CH=CH2

V"'o"

llff:iiilif',ft'' 73%

'#'f

I

A

N,.

".- (r" oFo

V...o"o*"r,

,ooJr,, "",

CoE : C-

HCI THF qumL

I' rhenylsulfonyl)-ALisoxazolines I r.rriousnucleophiles.'

"o!o

' J. Das,Syn. Comm.,lg,907(l9gg).

:

KOH \H,OH 92%

Phosphines,chiral. Hydrogenation catarysts. A numberof new opticalryactivephosphinerigands have been developedfor selectiveenantioserective reductionof N:c bonds of aminoacidprecursors,includingDpCB(l)r, the methylenehomolog(2), of dipamp, and the novel rigand3, in which the sourceof chiralityis a Re uton.,.,e ligand4 hasbeenusedas a Rh(I) complexfor hydrosilylation.a

I D. P. Simmons, D. Reichlin,andD' Sku'v'I

Phosphoric acid

o-CH.OC.H....

(CuHJrq.

/P1 c.H,-

(CrH,)rP!

CuHt.. "p-J /

)

I (DPCB) o-CHTOC$/

!",

,

(CrH,)rP-(A)

P...rtc,H,), (c.Hr)f/Re\No 3

.."ro'l-

dl Phosphorusoxychloride (Phosphoryl studit early Although Dehydration. lit shownto involve an anti-elimination' (Z)-alke (E)or of appliedto preparation and i "t tg> and (Z)- A22-or A2lsterols' trisubstitur of alkenesfor isomerization

CHt\or)\/

: CuH,

CH' -s-!

4

,T.Minami,Y.Okada,R.Nomura,s.Hirota,Y.Nagahara,andKFukuyama'chem' (1986). Letters,613 'C. R. iohnsonandT' Imamoto,l' Org'' 52,2170(1987)' chem.,lnt'Ed.'26, andJ.A. Gladysz'Angew. 3B. D. Zwick,l. M. Arlt, A.-i. puuo"n, 910(1987). 'A. F. F. M. M. Rahman andS' B' Wild,tbtd"39' 155(1987)' Phosphoricacid. The enol acetate(2) Cationic olefin cyclizationof aldehydeenol acetates't ofcitronellal(l')undergoescyclizationtodihydrocyclocitral(3)inthepresenceof

CH, A, CH,

o

I J.-L.Giner,C. Margot'andC' Dlerass

CH.

H

KOAc, AcrO, N(CrH), 80%

,

A z', I CH,l \

cH,

3 = 18:1 49-52Vo (translcds) SnClo,CHrClr, " = 16:1 42Vo 0o cH"so"H, c6H5CHr' " e.l 8o4a H"Po";c.HrCH3,1o0"

2 G I Z= 2 : t )

eitherLewisorBrdnstedacids,Cyclizationisachievedinthehighestyieldwith obtainswith Lewis acids, g57oaqueousphosphoricacid. Hilher stereoselectivity of 4 to the drimane 5 is but the rate is slower, and the yiJtd lower' Cyclization provides5 in I4Vo yield' best achievedwith Snclr. In this case,use of H:PO4

PhosphorusPentoxide,P2O'' 1' i-A^fno'6-arylaminoPurincs' p be can haveusefulbiologicaleffects' and P with an arylaminehydrochloride

o tl

rlr HrN

ANt

N

)

* *ttq

N H

I

R=C.}l R = p-FQ p =;-Cll

OAc ..CH,

I E.-S.M. A. Yakout,H' M Soe'and E

4 (Elz= 2:r)

PhosPhorusPentoxide

267

I D. P. Simmons,D. Reichlin, and D' Skuy, Helv',71, 1000(1988)'

Phosphorusoxychloride (Phosphorylchloride)' POCI.' were iehydration. Although earlystudiesof dehydrationof tertiaryalcohols been has shown to involve an anti-elimination,little use of this stereoselectivity

9",

.,"ro'1ff

appliedtopreparationof(E)-or(Z)-alkenes.Thisreactionisusefulforpreparation of oi (n)- and (Z)- A22-or An-sterols,and in combinationwith syn-hydroboration alkenesfor isomerizationof trisubstitutedsteroidalalkenes''

\ CHr\,OrA-y' /* .P(c,ur), tt-ao CuH, 4

\riahara, and K. Fukuyama,Chem.

,,u,J*',,.,

l'vr- 1

Int. Ed.,26, Angew.Chem., C;.,'Jvsz.

CH,

l r : r1 9 8 7 ) .

CH,

ol acentes.t The enol acetate(2) !r ,i.'clocitral(3) in the presenceof CH'

o \ : -.----, ;

3 = 18:I :9 -524o (translcis) " = 16:I 42Vo C" " =8:1 8 0 9 o O , :;:reved in the highestYieldwith e .:;:rvity obtainswith Lewis acids, lr;.izationof 4 to the drimane5 is H PO. provides5 \n l4Vo Yield. Cll.

rJ.-L.Giner,C. Margot,andC' Djerassi,J. Org',54'369(1989)' Phosphoruspentoxide,P2O.. i-Amino-6-srylaminopurines. Theseinterestingpurines(2)' many of which reaction haveusefulbiologicaleffects,canbe prepareddirectlyfrom guanine(1) by at 200''l (CrH')'N'HCl of presence in the PzO, and with an arylaminehydrochloride

N(qH,,

T\\

H,NAN

\,+\ ",*A*Ail' NHR

o + RNHT.HCI

t'o'

,

I R = CoHs p = p-FC5II R = m-CH:Cell

SOVo 6l7o 82Vo

I E.-S.M. A. Yakout,H. M. Soe,andE. B. Pederson, Acta Chem'Scand''B,42'257(1988)'

26

Platinum(IV) oxide

Caution: explosiveand toxic. Picric acid (2,4,6-trinitrophenol). Picrates.r At one time organicbaseswere isolatedand identifiedas the picrates,which are often highlycrystalline.Picricacidis generallysuppliedas a moist solid containingwater, which hinderscrystallizationof picrates.The water can be replacedby ethanolfor storage.Picratescan be preparedby reactionin acetone, in which picric acid is fairly solubleand then allowedto crystallizeby addition of ether.

Polyphosphoricacid trimelhylsilyl cstc

(1). Preparedas a mixture of four col in CHrCl2.Solublern t methyldisiloxane It efiectsa synthesisof amidinesfron

I D. LloydandH. McNab,J. Chem.Res.(S),18(1989).

(PDB), 1-Piperidino-3,3-dimethyl-2-butanol

I D. W. Cameron,G. I. Feutrill.and P. G (

* / - - \ (CH3)3CCHCHTN / |

(1).

\___J

OH

+ C.H.N{ C6H5COOH

I wittr piperidine The B-aminoalcoholis preparedby reactionof (CH3)3CCCU,Br acid followed by reductionwith LiAlHa. Resolutionwith ( - )-dibenzyl-t--tartaric provides(-)-1, oo -72" (98Voee). Enantioselective addition of (C{IslzZn to C,II'CHO.I In the presenceof ( - )-1, diethylzincaddsto C.H.CHO to providethe (R)-adduct.The opticalpurity of the catalyst(1) has a marked efiect on the rate and also on the optical purity of the adduct.Thus (-)-PDB of only l0-20Voee provides(R)-l-phenylpropanol in 80-90% ee and about 95Vochemicalyield. This nonlineareffectin catalyzed asymmetricoxidationsand aldolizationshas been noted previously.2It may be a resultof the molecularityof the reactionor of the aggregationor ligandexchange of the catalyst. ' N. Oguni,Y. Matsuda, Am. Soc.,1f0,7877(1988). andT. Kaneko, I C. Puchot,O. Samuel, E. Dunach,S. Zhao,C. Agami,andH. B. Kagan,Am. Soc.,l0E, 2353(1986). Platinum(IV) oxide (Adam's catalyst,1, 890). 1-Deoryanthracyclines.r Hydrogenation of anthracyclinesla or lb catalyzed by Pd/BaSOagives7-deoxy-l(97Voyield), which on further hydrogenationis converted into a 5,7-bisdeoxyproduct. However, hydrogenationof I catalyzedby Adam'scatalystin methanolcontainingchloroaceticacidaffordsthe 5-deoxyproduct 2 in aboutTIVoyielc.

This reagentis both a Lewis aod of sulfoxidcrr Pummererrearrangement via an epoxide.2 OH

I

(c^H.)"cH-cH(c^H.),t.r,l.'i.

l - " -

OH

800 150"

I S. Ogata, A. Mochizuki, M. Kakimoto. e

( le86). r M. Kakimoto.T. Seri.andY. Imai.ibrd. t

Potassium. Demethoxylation.t 1-Alkyl-3.{.>t on trealn alkyl-3,5-dimethoxybenzenes sodium or potassiumcan be used to t zene(85% yield). dimethoxyben

o

o o H cocH,R

l(TU

"oH

OH

c

O Sugar

la,R=H

rb.R=OH

o )

O Sugar

ocH3 r u . Azzena,T. Denurra, E. Fenude.G.

Il

Potassium

269

rD.W.Cameron,G.I.Feutrill,andP'G'Griffiths'TetrahedronLetters'29'4629(1988)'

fe ,rndtoxlc. rL:cJ .rndidentifiedas the Picmoist r. rcnerallysuPPliedas a be can water n .,t ni.rate.' The acetone' in rcl.rrcd bY reaction of ,".i ,,, .rYrtullizebY addition

f/s \l) l{ il

ester(PPSE)'(cH')rsio-k$-o7f-lstttn"' acidtrimethvlsilvl Polyphosphoric

l_ ositctti,l, of PtO' with hexa(1). Preparedas a mixture of four componentsby reaction solvents'l aprotic in CHrClr. Solublein most methyldisiloxane It effectsa synthesisof amidinesfrom simplecarboxylicacidsand amines':

I

:1{ cqHcH,N I OH

)

(1)'

NC.H.

r-----v

o

ll I r ( I I,).CiCHrBr with PiPeridine acid rrlh ( - )-dibenzyl-r--tartaric

c.H,[r'mc'u'

+ cuH,NH, c6H5cooH ffiff'

agent' Thus.it effects This reagent is both a Lewis acid and a dehydrating pinacolto pinacolone of rearrangement and pummererrearrangement of sulfoxides via an epoxide.2

In the Presenceof (fl,CHO) f,. *t-uOOu.t'The oPticalPuritY ,,. .,n,.talso on the oPticalPuritY r rr,,, ides (R)-1-PhenYlProPanol catalYzed Tl'- nonlineareffectin It maYbe a Bnrrrtcd previouslY'2 exchange h. r{gregationor ligand -rr7 (1988)' 'Kagan' llo Am' Soc'' 10E' ,"] .,"0H. B

La or lb catalyzed ri .,nthracyclines is conch ''n further hydrogenation bY catalYzed 1 of . hrJrugenation prod5-deoxy the *.,,. o."idaffords

o T"

I

H ^"

* c6Hid-c(c6H5)3 cuH,

617a

800 1500 I S. Ogata, A ( 1986).

lol

o

(ctlcr)r c'Hs-f\'tu't ) (c6H5)rcH-qH(c6H5)2 I c6H5 OH

26Vo 977o

Soc'Japan' 59' 2171 Mochizuki, M. Kakimoto, and Y' Imai' Butt' Chem'

: M . K a k i m o t oT, Seri.and Y. Imai, ibid.'61,2643(1988)

Potassium. Demethoxylation.tl-Alkyl-3,4,5-trimethoxybenzenesareconvertedintolon treatmentwith potassiumsand in THF Either alkyl-3,5-dimethoxybenzenes sodiumorpotassiumcanbeusedtoconvertl'2'3-trimethoxybenzeneintol'3(85% Yield)' dimethoxvbenzene

K. THF, 20" '12-81%

O Sugu

ocH3 28 (1989). G' Melloni'andG Rassu,Syntftesis, T. Denurra,E. Fenude, Azzena,

270

Potassium3'aminopropylamide

Potassium-l8-Crown'6. in THF cleavageof p-lactones.r The blue solutionof potassium-18-crown-6 protonation on -20" (1) which to furnish a dianion cleavesB-propiolactoneat usedto obtain givesmethyl acetate.A similar reactionof the p-lactone2 canbe isopropylproPionate(3)-

.

o

o

.

f

r

-@, x'l)-ocr,@# cH,E-ocH,

A"

Potassiumt-butoxide. Haller-Bauer reaction.t A studl o activetertiaryc-phenylketone(l)'stx with metal amidesin benzeneand all
nitrones,r This oxidation is possiblewith KMnO. under phasetransferconditionsin aqueousCH2CI,in 15-90Voyield. The best catalysrsare BuoNClor (n-CrH,r)oNBr.

n4

Potsssiumpersulflte

C.HTCH:NC(CE),

o ll

* .,c(cH3)3

Ylo;l"l;X'' ..j]:%%: C.H,CH:N'

+C.H.CNHC(CH3)3

\o-

I K. Shimamoto and Y. Ohfune. Tetrahcd r C. S. Pande and N. Jain, Svn. Comtn . I

,r,a\ (89Vo) 2-Hydroxy-3-oxocarboxylic esters.2 B-Alkyl-a,B-unsaturatedesters (1) are oxidizedto theseesters(2) by KMnOo in mildly acidicaqueousacetoneat 10" in 60-857oyield.

Potassiumsuperoxide,KO:. Arene oxides.t KOr convertsl-n sulfurradicalthat effectsepoxidationr solventsat -30'. Anthraceneis conr l(

CHrCH:C-COOCH3 I CH,

o tl-,C

CH.C -::--' - , / 8 0 %

\

I

\./

;- COOCH,

ct

OH

CH, )

I

rD. Christensen J. Or9.,54,126(1989). andK. A. Jorgensen, r D. H. G. CroutandD. L. Rathbone, (1989)' Synthesis,40

PotassiumpersulfaterK2S2O{i. Benzylic oxidstion (11, 441).' Oxidation of the N-Boc-L-tyrosine1 with with cuSo, as catalystgives the syn-cycliccarbamate2, which can be K2S2O8 convertedto the p-hydroxyamino acid 4 as shown. O-C:O

Desulfuration 2 Thioamides arc (13,260).The req tassiumsuperoxide caseof N-(2-hydroxyphenyl)thioam vield.

cHroAc rff-acH'oAc i

l

|

NHBoc

KS,o.,cuso. 76qo

cH.o)V

S

Hll

' cHro

NCC6H5

I ty na1oul, l0o7o B@,o I2)

OH

' H. K. Lee, K. S. Kim, J. C. Kim and \' :Y. H. Kin, Y. I. Kim, H. S. Chane.and

\ cH3o

4

OH

COOH

l) Po,, q 2) TFA ra459o

cH3o

o + 4KO, -

2 (37:l)

3

RCOOH -'+ RCOOOH.2 This oxidant convertswater-insolublecarboxylic acidsto the peracidin ether or CHrCl2under the influenceof benzyltriethylammonium chlorideor polyethyleneglycol (PEG-400).

Pyrazinium chlorochromar". f ) \'/ H yield pyrazine by reaction of in ( 80Vo of alcohols. The rea Oxidation alcohols.'

Pyrazinium chlorochromste

o tl

/ - t H r

+ C6H5CNHC(CH3)3

275

' K. Shimamotoand Y. Ohfune, TetahedronLetters,29,5177(1988). ' C . S . P a n d ea n dN . J a i n ,S y n .C o m m . , 1 8 , 2 1 2(31 9 8 8 ) .

(IIVo)

esters(1) are .e-unsaturated rJr. aqueousacetoneat - l0'

Potassium superoxide, KO2. Arene oxides.t KO, converts 2-nitrobenzenesulfonyl chloride into a peroxysulfur radical that effects epoxidation of polyarenes to give arene oxides in aprotic solvents at -30". Anthracene is converted into the 9,I0-quinone (70Vo yield).

foct

[^rno' \r'

4'\

I _=+_%(Y

-coocH" -( '.. /

,Ko,

OH

ll

"r-<J

:

o

a

9

cuH,+

K,Soo

I H. K. Lee, K. S. Kim, J. C. Kim and Y. H. Kim. Chem.Letrers,561(1988). rY. H. Kin, Y. I. Kim, H. S. Chang,and D. C. Yoon, Heterocycles,29,213 (1989)

-ClCrO,

Pyrazinium chlorochroma n, a

\fr

(1). The reagent is obtained in

H

carboxylic n. \\ater-insoluble amn:lurnceof benzyltriethyl

80Vayield by reactionof pyrazinein 6M HCI with CrO.. Oxidation of alcohols, The reagentis comparableto PCC for oxidationof alcohols.'

n6

Pyridiniump-toluenesulfonate

I G . J . S . D o a d , J . C h e m . R e s .( S ) , 2 7 0 ( 1 9 8 8 ) .

Pyridinium bromide perbromide. can be obtained in a-Bromo-arp-enones.r cr-Bromo-a,B-cyclopentenones with this reagent(about 3 equiv.) and good yield by reactionof cyclopentenones pyridine(3 equiv.) in CHzClz.In the absenceof pyridine,yieldsare lower because of polybromination.

a

o

o

Py.HBr.Br. PvrcH,CL

R

R = CHr R = CHzOBzl

A-_",

q

Quina alkaloids. Ch iral sulfinates, (CH. ).C5(O by reactionof r-butylmagnesium I carriedout in the presenceof an op active.The highestenantiosele.c with (-)-quinine (1). Examole:

R

(PrO)rS:O + r-&

57Vo 86Vo

' W. G. Dauben Syn.Comm.,lE, 1323(1988). andA. M. Warshawsky, Pyridinium chlorochromate(PCC) 1,2-Diketones.t Alkyl benzylketones(L) are oxidizedby PCC in combination (2) in 80-85Voyield.This oxidationfailswith dialkyl with pyridineto 1,2-diketones ketones.

+rcc ffi c5H5cH2coR

Asymmetric redaction of trlct with quinidine(1) asa proton sour of HMPT increasesthe rate and tl

o il

o o

c6Hr-c-ccrl

c.n,l-[n

o

ll

I (R = CH,, CrHr) I F. Bonadiesand C. Bonini, Syn.Comm.,18,1573(1988).

Pyridinium p-toluenesulfonate. Selective cleavage of t-butyldimethylsilyl ethers, This reagent cleaves t-butyldimethylsilylethersat 22-55' in 80-92Voyield in the presenceof l-butyldiphenylsilylethers. rC. Prakash,S. Saleh,and I. A. Blair,Tetrahedron Letters,30,19 (1989).

' J. Drabowicz,S. Legedf. and !1. Mrl r S. Takeuchiand Y. Ohgo. Chem Ia

en:.:t()nes can be obtained in tr. r'..rg!'nt(about 3 equiv') and ir:.irrc. f-ieldsare lower because

o ll

\

-Br

t'

R

Quina alkaloids. can be prepared Chiral sulfinates,(CH3)3CS(O)OR.' Alkyl r-butylsulfinates chloride with dialkyl sulfltes.If the reactionis by reactionof t-butylmagnesium carriedout in the presenceof an opticallyactiveamine,the productscanbe optically active.The highestenantioselectivity is observedwith aminoalcohols,in particular with (-)-quinine (1). Example:

(CH3)3CsoPr

@rO),S:O+ r-BuMgCl #

o (R,747o ee)

. l r r . r l 3( l 9 8 t t ) .

I ,.rrJrzedbYPCCin combination d I hr. oxidationfailswith dialkyl

Asymmetricreductionof benzil.2 Reductionof benzilwith SmI,in C.H./THF with quinidine(1) asa proton sourceyields(R)-benzoinin about40Voee.Addition of HMPT increasesthe rate and the enantioselectivity to 56Voee.

o ll

.

:.

tvrs

l

o o l l l

C^H5C-CR

I

I ethers. This reagent cleaves i rrcltl in the presenceof r-butyl-

1 . ,: : ." . 3 0 , 1 9 ( 1 9 8 9 ) .

o

stnl. I,

ll

C6H5-C-CC6H5 + i

o

tl ll

uMr

l

o

.

C6H5C-CHC6H5 l

H

(R,567oee) I J. Drabowicz,S. LegedZ,and M. Mikolajczyk,Tetahedron,4,5243 (1988). rS. Takeuchiand Y. Ohgo,Chem.Letters,403 (1988).

propane,which rearrangesreadi\ pane(2) canbe isolatedin the cas by a l% H,SO. solutionto the ke

t'"'*+No2

(cHJ'rcHoH ) "'"'*+NH'+

o

a-\--n

Raneynickel (1). Transfer hydrogenation o;f nitroarenes.r Transfer hydrogenationof the nitroarene2 with Raney nickel and isopropanolas the hydridedonor resultsin the

9oA1cH;,J*x,

(ct[)'c:o

*#Fu,*ON:c(cH{

A typicalreactionis formulate amine5, formed via the unstableimine 4. Other alcoholscan be used,but increase in the bulk resultsin lower yieldsof the final product. A similarresultobtainson transferhydrogenationof 2 with Pd-HCOOH in the presenceof isobutylmethyl ketone (equationI) to provide6.

rv orr

tt' C\,"H2),cocHN2

cHrr

r.su)c=o'p*c, o 2-1g9i999r,3 F",*-G.:.(::l xcmx rm* Jearc,

.,",*eFfi-E{:, 6

p-Lactams.2 Decomposition with Rh,(OAc), in refluxingbenec acetylgroup on the diazo carbon i bond ratherthan reactionof the ce

o (cH3)3c\ lL -coc -Ntl

Brl/" I A. A. Banerjee (1988). l.C.S.Chem.Comm.,1275 andD. Mukesh, Rhodium(Il) carboxylates. Cyclopropanationoffuranyl diaZo ketones.r The reactionof o-diazo ketones of furanylpropionicacidswith Rhr(OAc), involvesformationof an unstablecyclo27E

N. I

rsalsoessentialfor high yields.Ins over insertion into a 1-C-H bon rhodium(Il) benzoateas caralvsr.

Rhodium(Il) carboxylates

2T,

propane,which rearrangesreadily to a cyclicketone.The intermediatecyclopropane(2) canbe isolatedin the caseofthe diazobenzofuran1 andcanbe isomerized by a lVo H'SO, solutionto the ketone3 or rearrangedthermallyto 4'

of the nl1r.rnsferhYdrogenation in the results donor ,. the hYdride

I

rro" I---rr"1

(cH')'c:o

,..nONH,+

'[o,*O*:",t*'] 4 increase (l:r;r alcoholscanbe used'but [:..' rroduct' Pd-HCooH in the ;r,'..^;i;" of 2 with t r r ' : r I ) t o P r o v i d e6 '

A typicalreactionis formulatedin equation(I)'

&!?'lil" t"(\,.H,),cocHN2 lW]

-'

S"" o

[,''"+*:'(::1 '*'" I *""' "t*n *

l-\

4 \7cH' t.rr.ru{ ) " t-"u-, \-./ 6 ' h ,"

( o t n m, 1 2 7 5( 1 9 8 8 ) '

of a-diazo ketones t Letttnes.t The reaction cycloformation of an unstable :. .'';';i".t

(1) p-Lactams,2 Decompositionof N-benzyl-N-t-butyldiazoacetoacetamide yield. The 2 in 98Vo xitrr Rh,(oAc). in refluxingbenzeneresultsiq the B-lactam g-C-H rcetyl group on the diazo carbonis necessary'forthis insertioninto the group t-butyl The ring' aromatic bondratherthan reactionof the carbenewith the

o *%l{"",""'l- ' to Rh'(oAcL ? tcH,),c--NA.cocH3 | -r. e8% Bzr/

Jt, t

c.Hr"'-N-.c(cH3)l 2

favored rsalsoessentialfor high yields.Insertioninto a B-c-H bond is generally of a use r)\,erinsertion into a 1-c-H bond and can be further enhancedby rhodium(Il) benzoateas catalyst.

2E0

Ruthenium(Ill) chloride-Tributylphosphite

I K.-T.Huh,Y. Tsuji,M. Kobayashi. F.O\ud..

o

.

(,-P,),N\H---* *" N,

Rhr(OAc)o Rhr(OCOAT)4

cHr't-N\pr

ffo

Ruthenium tetroxide. RCHrNH2 + RCONHz.| The tramf, can be effectedby oxidationof N-Boc alkl eratedin sitrzfrom RuO, (catalytic)and \ Deprotectionis effectedwith TFA in CH,t

cHrh*-*r-,

-i 4.2:l 6.2:l

95Vo

c-Sityl estersor ketones.s Decompositionof a-diazoestersor ketonescatalyzedby Rhr(OAc),,in the presenceof a trialkylsilaneaffordct-silylestersor ketones in 85-95Voyield. + (CrHr),SiH#-NTCHCOOCTH,

NaIO. ? C,H,CH,NHBo. C,H,iNIBoc I #

(czHs)3sicH2coocrHs + BocNH(CHr)rCHrNHBoc

Diazo ketone cyclization to hydroazulenones.a This reaction can be accomplishedin high yield under high dilution and efficientstirring to minimizebimolecularreactions.

#"oq @**:foql cHN,

L

'bl

I A. Padwa.T. J. Wisnieff,and E. J. Walsh,./. Org.,54,299(1989). : M. p. Doyle,M. S. Shanklin,S.-M.Oon, H. Q. Pho,F. R. vander Heide,andW. R. Veal, ibid., s3,3384(1988). 3 V. Bagheri,M. P. Doyle,J. Taunton'and E. E. Claxton'ibid',53,6158(1988)' r L. T. Scottand C. A. Sumpter,Org Syn',submitted(1988)'

Ruthenium(Ill) chloride-Tributylphosphite. N-Methylation of anilines.t This system activates methanol for N-methylation of anilines. RuCl.[P(CuHs):]. is more effective for N-methylation of N-alkylanilines.

G*,+

*o"Li"oP"", cH,oH $*,.n,,,* 807o

C6H5NHCH3+ CHrOH -+ RuClr/P(OBu[ RuClr[P(C.Hr)r] z

C64N(CE), 60Va 829o

GNHCH3 6Vo

Boc\}lt(

' K. Tanaka,S. Yoshifuii.andY. Nitta.Chca

Ruthenium tetroxide

' K.-T.Huh,Y. Tsuji,M. Kobayashi, F.Okuda,andY. Watanabe, (1988). Chem.Leuers,449

avo \ /

Ruthenium tetroxide. RCH,NII, --->RCONHz.I The transformationof primary aminesto amides can be effectedby oxidationof N-Boc alkylamineswith rutheniumtetroxide,generatedin sit, from RuO, (catalytic)and NaIO, (excess)in aqueousethyl acetate. Deprotectionis effectedwith TFA in CHrClr.

cH.|N-pr-: : J:.:z,restersor ketonescataf.,rJ o-silylestersor ketones

O Natol

C,H,CH,NHBo. C,H,iNTIBoc # ff

BocNH(CHr)rCHrNHBoc

Thr. reactioncan be accomIt .:rrringto minimizebimo-

.e s 9 ) . r J.'rHeide,andW.R. Veal, : . s 3 .6 1 5 8( 1 9 8 8 ) .

for N-methYlar:.. methanol of N-alkYlh.r \-methylation

i,cH,r,+( \:./

llrucH, 6Vo

c,H,coNH,

o

l. S:CH,COOCTH,

9^.

281

tl

;+

o

tl

BocNH(CHr)rCNHBoc ----+ H2N(CHJ2CNH2

I K. Tanaka,S. Yoshifuji,and Y. Nitta, Chem.Pharm. Bull.,*.3125 (1988).

-l

J Samarium(Ill) chloride. Pinacol condensationl This reaction can be effected with stoichiometric amountsof SmXr, which is not availablecommercially.The samereactioncan be carriedout with SmCl, a stableand relativelyinexpensivelanthanide,in catalytic reaction.Evidently,electroamounts(5-I0Vo) if conductedas an electrochemical species. active divalent the regenerate synthesiscan

Note that similar cleavageof I with sodium,which givesalmostp or the tr4r?s-isomer. Reductive cyclization.2 Red in THF/HMPT (20:1) at ff efec disubstitutedcyclopentenesvsteu high cis-anti-cis-stereoselectivin _ H

c

:1

CH. CH,

o

HO

l

, ll . --;_r8%,'.r. ntr, *"

OH

l

R,C _ Cl _ R " t l ^ 1 , R" R'

2 R'CR'

meso (+)

o!

I

Cyclopropanols,t Reaction o acid chlorides(1) resultsin doub cyclopropanering.

I E. L€onard,E. Duflach,and J' P6richon,J.C.S C h e m . C o m m . , 2 7 6 ( 1 9 8 9 )

2r:,a,COCt Samarium(Il)iodide. Cleavageof p-chlorotetrahydrofurans.r SmI2cleaveseither cis- or trans-P' (1) at reflux to give the (E)-unsaturatedalcohol chloro-cr-methyltetrahydrofurans (4) and (E)-enynols(6)' (E)-dienols provide 2. This cleavagecan

CI f
CH3 smrr.

/H

1s-.,%{l:;;t""

(4o."..,, t

Decarbonylation of a-alloty acid chloride with a ketone medu and liberationof CO. The necess SmIr.a

o il

I

O + CH,OCH,CC

cl /

\

-

\oAa":an,

)'0" CHr:9116t:CH(CHJzOH 4 (E' >97Vo)

u,p-Enones.s a-Haloketoncs o.B-enones(equationI). Praaical

3 CI /

2,Ei2

/

\ -o'

\

'c:cc5Hil

84qa

C5HrC=C - CH: CH(CHz)zOH 6 (E, >99Vo)

o tl

c.HrccHrBr

Samerium(ll) iodide

.,1:, be effectedwith stoichiometric The samereactioncan be nn-..rcially. rl', ::e rpensivelanthanide,in catalytic N::mrcalreaction.Evidentlv.electro-

Note that similarcleavageof c-alkyl-B-chlorotetrahydropyrans is best effected with sodium,which givesalmostpure (E)-unsaturated alcoholsfrom either the crs_ or the /rdlxs-isomer. Reductive cyclization.2 Reduction of the unsaturatedaldehyde r. with SmI, in THF/HMPT (20:l) at 0'effects a tandemradicalcyclizationof the trans-3,Sdisubstitutedcyclopentenesystemto a linear triquinaneunit (2) with surprisingry high cis-anti - crs-stereoselectivity.

cH.

! lr Jlc-5.

HO

o; t".1frilr., ""sB%

oH

J

. R C_C_R2

2

I

R- R, neso (+) ,

293

cyclopropanols.s Reactionof SmI, (2 equiv.) at 25" with 2-allyroxybenzoic acid chlorides(1) resultsin double cyclizationto tricyclic productscontaining a cyclopropanering.

:,,'r Comm..276 (1989)

cocr t

:nrll cleaves either cls- or trans'Ptr :.'give the (E)-unsaturatedalcohol | . , r J ( E ) - e n y n o l s( 6 ) .

li r('il,'.OH

OCH,CH:CH,

,nil!,"dx -;-\4",J

I

Decarbonylation of a-arkoxy acid chrorides. The reaction of an o-alkoxy acid chloride with a ketone mediatedby SmI, resultsin a r,2-grycol monoether andliberationof co. The necessary molarratiosare2:r:4, acidchloride/ketone/ SmIr.a

o

G".

rHF. ll CH.OCH"CCI + Sml,' -i1+

ll{('tt:CH(CHr)rOH 4 i >97Vo)

:=C -CH:CH(CHr)rOH 6 (8, >99Vo)

OH

53q"

cHrocH,

+ co

urp-Enones.s c-Haloketonesreactwith aldehydesandSmI,(l equiv.) to form c,B-enones(equationI). Practicallyno enonesform if 2 equiv. of SmI, are used.

o ll

f

t) Sm!,rHF

cuH,ScH,Br #

l

c'H'c:aH E, t00vo

Semicarbezide

'L. CrombieandL. J. Rainbow,Tetrahedron (1988);L. CrombieandR. Letters,29,6517 D. Wyvill,J.C.S.Perkin1, 1983(1985). 2T. L. Fevig,R. L. Elliott,andD. P.Curran, (1988)' Am. \oc.,110,5064 3M. Sasaki, (1988). Letters,29,6105 J. Collin,andH. B. Kagan,Tetahedron aldem,ibid.,29,4847(1988). 5\. Zhang,T. Liu, andR. Lin, Syn.Comm.,18,2003(1988).

N_N

N_N

"",{r\r-r4r\*,

Samarium(Il) iodide-Tetrahydrofuran-Hexamethylphosphorictriamide. Deorygenationof oxides.t Sulfoxides,sulfones,N-oxides,and phosphineoxides can be deoxygenatedby SmI, in THF/HMPT at20-65". HMPT is essential for high yields. 1Y.Handa,J. Inanaga, (1989). Chem.Comm.,298 andM. Yamaguchi,./.C.S.

rS. N. Mairi,M. P. Singh,p. Spevak. R G y (s),256(1e88).

(SeCN)r.Preparation.r Selenocyanogen, (13' 286) via selenocyanates of selenoaldehydes Selenoketones.2The synthesis selenoketones Electron-deficient of selenoketones. hasbeenextendedto a synthesis are simplypreparedby reactionof halideswith KSeCNfollowedby base-induced eliminationof HCN (equationI). However,this routefailsin the caseof precursors

Silica Hydroryisoxazolidines,t The rerto tonaldehydein methanolresultsin a minr and 2) in which the former isomer pred

X a

o) n'Ern'#

Ks"cN,

SeCN I

--+ CH,CH:CHCHO + C.HTCONHOH

Se ll

R'Cnn'-Yc'Ii5P'lP'

llB*'i'.

-ffi (rDcH3cHrsorcu",

/ \ H3C1o,:

lecN

cH,iHsorcuH, #

fr'

cH,cso,cuH,

groups.In this case,the selenocyanate is obtained containingelectron-accepting preparation with as shown for the cyanocuprates, reaction of selenocyanogen by (equationII). of phenylsulfonylmethyl selenoketcine TheseketonesundergoDiels-Alder reactionswith dienesto give selenopyrans good in to excellentyields. ' L. Birckenbach andK. Kellermann, &er.,58,786(1925). 2P.T. MeinkeandG. A. Krafft,Am. Soc.,110,8679(1988). Semicarbazide. Cleavageof disulfides.t Diaryl disulfidesare cleavedto thiols by semicarbazide in CH2CIr-CH3OHat room temperaturewithin 2 hours. Cleavageof di-

proceeds morereadily thanthatof diaryldisulfldes, disulfrdes heteroaryl

CH3OH,5-7 hr.60Vo SiOr,30 min.80-9OVo DEAE-cellulose, I hr. " 6 hr.95-98% Cellulose, 437o

I

markedlyincreasedwhencarriedout on ao i conductedon SiO, is completewithin 3O-{ only. Reactionsconductedon diethylaminc in a mixture of 1 and 2 in the early stagcsr Apparentlythis adsorbentcan convertI ifl itself has slight efiect on the rate and provil yieldand in the ratio 75:25. I I. A. Motorina,L. A. Sviridova, G. A. Golcb 30,117(1989),

2E5

o tl

I "ii- (1988);L. Crombieand R' N_N . llo s061(1988). z : : . , ' .2 9 .6 1 0 5( 1 9 8 8 ) .

TLNCNHNH,(r)

N_N

-----___----__< Ea%

.t./r\r-r{r\"r,

N_N

"r4r\"r,

: - \ \| flphosphorictriamide. oxe.. \-oxides,andPhosPhine [ ": ]0-65'. HMPT is essential tr'.( ,,mm.,298(1989).

(13,286) 1c.'.r ia selenocyanates E.r'.tron-deficientselenoketones Sc('\ followedbY base-induced u:e failsin the caseof Precursors

I, THF_CHpH

ct-
."."o

rn,.il,o",a."r;a"an,o 48qo

Sodium(potassium)amide. Haller-Bauef cleavageof u'silyl ketones. Paquette'sgroup2has shownthat reactionof Na(K)NH, with optically active ct-silylphenyl ketonessuch as I in refluxingbenzeneprovidesthe correspondingsilanes(2) with 88-927oretention control is observedin the cleavageof of configuration.The samestereochemical as 3. such chiral c-silyl benzoylcycloalkanes

c6H5c-_ cH2cH2c6H5 HL (cH3)3si/"'cH3

o ll

c6H5cv^/'cH3

(cH3)3si1JDH 3

--------)

Sodium azide-Dimethytror Selective cleavagc of RO. alcohol by NaN, in DMF ar , phenylsilylethers.

I S.J. Monger,D. M. Parn..and

Sodium benzeneselenohtc.r..t Cleavageof oxetana.t O 1-phenylselenenylpropanol ar lanes)are cleavedonly ar () attackedby the reagent.Clcarr

Hv,cH2cH2c6H5 (cH3)3si7"'cH3 2 (87Vaee)

| (897o ee)

' C. R. Johnson andO. [:r.cr!c r C. R. Johnson, Aldrichim.Aclr

cHi

'S. T. Purrington (1988). Leuers,29,685l Tetahedron andJ. H. Pittman,

o tl

o tl c4scl{' -

H>/

d_*

'x'cH3

rcH.)"Si1_,r/\H 4 (98:2)

$.no

rReview:E. M. KaiserandC. D. Warner, (1975). Synthesis,395 ' J. P.Gilday,J. C. Gallucci, L. A. Paquette' J. Org.,54,1399(1989); andL. A. Paquette, C. S. Ra,andM. Hoppe,ibid.,54,1408(1989). G. D. Maynard, Sodium anthracenide(1). The reagentis obtainedby sonicationof sodium and anthracenein DME. Sulfoximines, R';{OX'.' Review.2 The mostattractiveroute to theseimines NH is reaction of a sulfoxidewith tosyl azide in the presenceof CuXt or with Ointermediate. (MSH) to givean N-tosylsulfoximine (mesitylsulfonyl)hydroxylamine Cleavageof the tosyl group is then effectedwith a sodium arenide,in particular with sodiumanthracenide.

I K. Haraguchi, H. Tanaka.H. Hr

Sodiumbenzyloxide,C.H.CH:C benzylalcoholand NaH in Ttil Conjugate addition to io zyloxideundergoes4r?!i-seled

Sodium benzyloxide

o l

o l

o

l

l

l$t cn,frc", cH3ScH3 #

t r rr.rctionof mercury(Il) fluorrJc. bv reductivedesulfurization

l

l cH,frcH, NH

NTS

:l' l

....r.o" '

';]>"".'*

)--;-," r

(1988)' le. 61151

group2hasshownthat P.:.luctte's rlr rhenyl ketonessuchas I' in , d : r . ( 2 ) w i t h 8 8 - 9 2 7 or e t e n t i o n r.. :. rrbservedin the cleavageof

I C. R. Johnsonand O. Lavergne, J. Org.,54, 986(1989). r C. R. Johnson,Aldrichim.Acta,18,3 (1985).

Sodium azide-Dimethylformainide. Selectivecleavageof ROSi(CHrl(CuIIr)rJ These ethers are cleaved to the alcohol by NaN. in DMF at 40owithout effect on r-butyldimethyl-or t-butyldiphenylsilylethers. 'S. J. Monger, D. M. Parry,andS. M. Roberts, (1989). J.C.S.Chem.Comm.,381 Sodiumbenzeneselenolate, NaSeCuH,(1). Cleavageofoxetanes.t Oxetanesare cleavedby this salt to the corresponding at room temperature,whereastetrahydrofurans(oxo1-phenylselenenylpropanol lanes)are cleavedonly at 60-100". In each casethe less-substituted carbon is attackedby the reagent.cleavageof oxiraneswith thisreagentis not regioselective.

,. llxilfH2c6H5

r-o

2 (817o ee)

,:lt/.f' 1 (98:2)

:

.< le75). 5{. 1399(1989);L. A. Paquette. -, . r1989).

2E9

| | 4"",

"X"fn' f"'

-#

&%

HOCH(CH,)'SeC.H,

cH2oH

f]

-+T--'uoCH1cH,;,secuH,

\6^cH,oH cuHrse -_--+ 86qo

nr.i hv sonicationof sodiumand o . ' . r t l r a c t i vreo u t et o t h e s ei m i n e s

' K. Haraguchi, H. Tanaka,H. Hayakawa, andT. Miyasaka, Chem.Letters,g3l(1988).

thc presenceof CuX, or with G intermediate' n \ -rosvlsulfoximine in particular arenide, .odium .r th

Sodiumbenzyloxide,C.HTCHTONa (1). This alkoxidecanbe generatedin situfrom benzylalcoholand NaH in THF at 25". Conjugate addition to nitroalkenes; anti-p-amino alcohols.' Sodium benzyloxideundergoesanfi-selective conjugateadditionto 2-nitro-2-butenes to give2-

Sodium borohydride

(2). Theseproductsare convertedinto P-aminoalcohols benzyloxy-3-nitrobutanes (3) by catalytichydrogenationin acidicethanol. t

R

t

I){O,

NO, |

l)l.THF

,

ziHorq-re.,R:An, Not

5o-1Mo

*

R*nt

I

Sodium borohydride-Ceriur( Ilfl Reduction of diphenylphol thesesubstrateswith NaBH. aloa cohols,whereasLucheconditionsr

:

ocH2c6H5

ocHrc6H5

o tl

2 (85-94:15-6)

,_,*l[;ffi'".,

(C6HJ/-y pr-,

oA..*,,

;,

R\4n'

NaBH. NaBH.+ ese,

6" = 80-90:20-10) 3 (antilsyn ' A. Kamimura (1989). andN. Ono, Tetrahedron Letters,30,731 Sodiumbis(2-methoxyethoxy)aluminum hydride (SMEAH) (1). Reduction of 2,3-eporycinnamyl alcohol (2).1 This hydride can effect selective reductionof 2,3-epoxyalcoholsto 1,3-diols,probablyby initial attackof the free hydroxyl group followed by intramoleculardeliveryof the hydride. The regioselectivityis decreasedby useof excessreductantor increasedby the presence of a free alcohol(methanol).

...4 crH}hoH )

o tl

(c5H5)2P- cH3 _ I l -

o4^w,.

{

NaBHo + CcCl.

Selective reduction of lrlolrl,. sodiumborohydride reduceso-fnx to a mixture of o-mannitotand >g

OH

t'o"u , excessI,

c,nlion 3 (22:l) 4-9:l

lY. GaoandK. B. Sharpless, (1988). J. Org.,53,4081

Sodium borohydride. Chemoselectivereductions. The reactivity of NaBH,,can be decreasedby use of a lower temperatureor by a mixedsolventsuchas methanolor ethanolicmethylene chloride. This simple strategycan be used to effect selectivereductionof ketonesin the presenceof enones,'and of aldehydesin the presenceof ketones.: 'D. E. Ward,C. K. Rhee,andW M. Zoghaib, (1988). Tetrahedron Letters,29,517 ' D. E. WardandC. K. Rhee,Syn.Comm.,18, 1927(1988).

J. Elliotf, D. Hall, and S. Warren. Ia R. Roy, S. Gervais,A. Gamiean.aod

Sodiumborohydride-Cerium(Ill)chloride

into p-aminoalcohols r .,)nr'€rted

NO"

)

'P' * "

R-lR'

I

l ocHrc6H5 c.H. | .: 9'1: 15-6) I u, parc, s: - *fc,npu, Hct

Sodium borohydride-Cerium(Ill) chloride. Reduction of diphenylphosphinoyl ketones qnd enones.t 1,2-Reduction of thesesubstrateswith NaBHo alone normally reducesthesesubstratesto threo alcohols,whereasLucheconditions(NaBHoand CeCl,)canresultin erythroalcohols.

o l

l . oAc.H,

-:l (1989).

le :\IEAH) (1). This hYdridecan effectselecl: rl. :.robablyby initial attackof the a: .icliveryof the hydride'The reiu;:.,ntor increasedby the presence

-

-

Ho

-

o (C6H5)f

cuH,

l

o tl (c6H5)2P

tl

(c6H5)rPY'CH3

I oU\pr

---4 Tteo

Pr-t

threo -5 :95 95:5

907o

o

y

+ l Ho"'\c.H,

erythro NaBH4 NaBHo + CeCl,

I

)

o l(C,HJrPy,Pr-, l

l

(C6H5)rP-yPr-i

\TI, I R-'Ant OH rr = 80-90:20-10)

291

Y | go*pr

CH3 + threo-isomer

50:50

NaBHo + CeCl,

Selectivereduction of ketoses, In the presenceof a large excessof CeClr, selectively sodiumborohydridereducesD-fructose(1) in the presenceof D-glucose to a mixture of D-mannitoland o-glucitol(2).'

OH a

c.n:^*oH 3 (22:l) 1-9:1

^.

bYuse t\ ,,r \aBHi canbe decreased :u!h as methanolor ethanolicmethu.(J to effectselectivereductionof of ketones'2 dcnrdesin the presence tt :,..,:t'tlron Letters, 29, 517 (1988)' c-- ie88).

f

Nox., ccct,

2

J. Elliotf, D. Hall, and S. Warren, TetahedronLetters,30,60l (1989). R. Roy, S. Gervais,A. Gamiean,and J. Boratynski,CarbohydrateRes.,l77, C5 (1988).

2n

SodiumdichloroisocYsnunte

Sodium borohydride-tifluoromethanesulfonic acid, NaBHr-HOTf (1)' Ring expansion. Alicyclic groups attachedto a hydroxymethyl (-CHTOH) or in an ethecarboxylgroupundergoring homologationon exposureto NaOSOTCF, -78" ion't carbenium to 25' via an intermediate real solventat CH.OH

#(,

r J . Z a k r z e w sS k iy, n .C o m m . . l t . : l - 1(51

Sodium O,O-diethyl phosphorotclr Debromination.r The reagentc 74-89Voyield.

(

n; ..C.tL(qlqo{ I H..hH r.l

The samereagentconvertsunsaturatedpolycycliccompoundsto diamondoid cagehydrocarbons.2 I G. A. Olah,A. Wu,andO. Farooq,l.Org.,54'1452(1989). ' G. A. Olah,A. Wu,andO. Farooq, ibid.'54,1450(1989)' andG. K. S.Prakash, Sodium borohydride-Zirconium(IV) chloride. r The combinationof NaBHoand ZrClo Reductionof C:O , Q:ltt , anl (-:N. (4:1) reducesketones,oximes,and nitrilesin THF at25'in85-96Vo yields'ReReductionof oximes duction of c:N and GN is slower than that of Fo. as reductant). BrHu with (obtained hydroxylamines than rather amines affords rS. Itsuno,Y. Sakurai, (1988). andK. Ito, Synthesis,995 Sodiumbromite, NaBrOr, 12, M5. Oxidation of ROH.I This oxidant can be usedto oxidize alcoholsin CH2CI2 when it is supportedon alumina;yields are generally>90Vo.It is also usefulfor oxidationof sulfidesto sulfoxides. rT. Morimoto,M. Hirano,Y. Aikawa,andX. Zhang,J.C.S.Perkin1,2423(1988)'

? ctttAN-t.la. --l Sodiumdichloroisocyanurate' |

(1).

oANAo CI Supplier:Aldrich. Chloramines.l This reagentchlorinatesprimary and secondaryamines,but is most usefulfor chlorinationof hinderedamines.The reactionis carried out in water or benzene-water.The co-product,cyanuricacid, is removedby filtration.

o

o tl CH"-I

,\

-i-.#{..I!X,

I-CH.

cHIN H

crr,

CI

coH,

Br

The debrominationcan also bc el

o tl

(CrHrO)rPNa, and a catalyticamounr X. HuangandY. Q. Hou,Syn.Comn .

Sodiumhydrogen selenide. Dealkylation of esterc.t NaHSc. DMF, is effective for cleavageof este {75), but this reagentis more difrcult

F. Kong,J. Chen,andX. Zhou.Srn. Ca

Sodiumhypochlorite,NaOCl. Oxidative decarboxylation.t Sod decarboxylationof o-hydroxy carbon hydroxylgroup is not essentialsinceu thisoxidation.Thustriphenylacetic aor andbenzophenone. In the presence ofe

(C6H')3CCOOH

"ttt,C,

and the ketone becomesthe major prc oxidation of 2,2-diphenylpropanoicaor acetophenone in the approximate ratrc

P.R. Elmore,R. T. Reed,T. Terkle-Hrx t O r 9 . , 5 4 , 9 7(01 9 8 9 ) .

SodiumhYPochlorite

(1)' d. \aBH.-HOTf (-CH' oH) or l, n'aro*rttthyl in an etheJtlr. ,o NaOSO2CF' ,,=*n1g6 ion'r

a^) i

rJ. Zakrzewski, Syn'Comm''lE' 2135(1988)' E' 455;10,362. Sodium O,O'diethyl phosphorotelluroate' into alkenes uic-dibromoalkanes converts reagent Debromination't The 74-89VoYield.

l

Br

-\

('

q\9 ).

l,^.'tt'

'iUia' ' Sq'1450(1989)'

of NaBHoandZrCL c ;.,nrhination Re.tli'.'t ,t ,:i' \n 85-964oYields' oximes of ., C:O. Reduction reductant)' as B2Ho La'r..twith 9\\

alcoholsin CHzCI: : u-cJ to oxidize It is also usefulfor .".titt t**' l' 2423(1988)' 11; ,/ ('.S.Perkin

I

H')-tg '8,

comPoundsto diamondoid

t;.ri

,l)

c^H.

cuH,

!-

H

cuHr. " "\:1

. : - l - - ' 1--*"6,np;itena-

+Te

ctHt

H

Thedebrominationcanalsobeeffectedwithsodiumo,o-diethylphosphite'

o il

and a catalyticamountof tellurium' (CrHrO)rFNa, (1988) rX. HuangandY. Q. Hou,Syn.Comm',18,2201

SodiumhYdrogenselenide' in generatedin situ from Se and NaBHo Dealkylation of esterc'r NaHSe' (11' reaction this CuH'SeNaalso effects DMF, is effectivefo. .f"unugt of esters] and handle' prepare to difficult +ZS;,'Uu,this reagentis more lF. Kong,J. Chen,andX' Zhou' Syn'Comm''18'801(1988)'

Sodium hYPochlorite,NaOCI' hypochloriteis knownto effectoxidative Oxidativedeco'boryiotio''L Sodium a acidsto form ketonesand CO" but decarboxylationof o-hyJroxy carboxylic hydroxylgroupisnotessentialsincetrisubstitutedaceticacidsarealsosubjectto is oxidizedby Naocl to triphenylmethanol thisoxidation.Thustriplenylaceticacid andbenzophenone.Inthepresenceofaphase-transfercatalyst,therateisenhanced

I

Naocr + (c'Ht)'c:o + cot ' (cuH5)3coH (c6HJ3ccooH "Ti",":: :l:tn | .nmarv andsecondarl out carried is reaction ,r.,";.. The by filtration' ,"""tt. acid,is removed

o >.rr

a\ I

l-CH,

.,,)ooActt' CI

(13-201o)

(24-421o)

product (g\-g4vo yield). A similar, catalyzed and the ketone becomesthe major and providesa mixture of benzophenone oxidationof 2,2-diphenrfpl"p-Lit acid ratio of l:2:5' in the approximate acetophenone J' S Welch'S' M' Young'andR' G' Landolt' P.R. Elmore,R. T. Reed,T Terkle-Huslig' (1989)' J. Org.,54,970

294

Sodium phenylseleno(triethoxy)borate

Sodium molybdate(Vl)-Hydrogen peroxide' Na2MoOo-HrO'. Singlet orygen.t This combinationresults in sodium peroxomolybdenate, NarMoO6.This reagentcan be generatedon a macroreticularresin suchas Am10. berlystand usedas a chemicalsourceof singletoxygen,

Sodiumtetraborate(borax), Na:B.O-:rl.. Hydration of cyanohydrins.' Thc undergohydrationwhentreatedwith bora in 65-85Voyield. In somecasesadditiono

RCHC\#

ffYo"--*ffi

OH

65%

\,.\2

ooH ooH

I J. Jammot, R. Pascal, andA. Commerras li

I

(CHr),C:C(CHJ, J;+

(cH3)rc-ccH, tl

CTL : E. C. McGoranand M. Wyborney,Tetrahedron Letters,30,783(1989)'

Sodiuft periodate. Gtycol cleavagelquinones.t Glycol cleavageand oxidationof hydroquinones to quinonescan be convenientlycarried out in CHrClt with sodium periodate supportedon wet silicagel. Water is essentialand the amountis the most critical factor. The procedureovercomesthe problemof insolubilityof NaIOoin organic solventsand shortensthe reactiontimes to generallylessthan 15 minutes.

Sodium tetracarbonylhydridofernte. \a' I ArNO, --+ ArNHz.t Na-[HFe(COl.l medium.However, the bis(triphenr.lptro in combinationwith a strongBronstedrc ticularlyfor nitroarenes,even in the prcse

C.HrNOr+ppN'[l{F(CO

' P.L. Gaus,S. W. Gerritz,andP.M. Jefincs : M. Y. Darensbourg, D. J. Darensbourg. an ( 1978).

64 (1989)' I M. Daumas, andF LeGaffe,Synthesis' L' Vo-Quang, Y. Vo-Quang, (l')' L4' 284' Na*[C6H,SeB(OCzH'):]Sodiumphenylseleno(triethoxy)borate, substratesto pthese Reiuction of o,rp_epoxyesters.t The reagent reduces

Sodiumtungstale,NazWOr. Oxidation of sec-aminesto nitroet. drogenperoxideoxidizessecondaryaminc

hvdroxyestersin 80-907oYield.

A

cH3(cHr)3N(cH)3cH3 H r

I

lqor orrol rir'\ro' e

r

/ \ cooc2Hr C2H5OOC c$ or tro'ns

f

o

H

l

| .,",oo"\cooc2H5 l t=;-

L

o H c,Hsooclcooc'r!

lecuH,J

r M. Miyashita,M. Hoshino,T. suzuki, and A. Yoshikoshi,chem. Letters,507(1988)'

H. Mitsui, S. Zenki, T. Shiota,and S.-1.Ill Org. Syn.,submitted(1988).

Sodium tungstate

). ll o.. i(\.llum peroxomolybdenate, orrircularresinsuchas Am?n.().

Z9S

Sodiumtetraborate(borax),Na,BoOT; 4, 46I. Hydration of cyanohydrins.t The cyanohydrinsderived from aldehydes undergohydrationwhentreatedwith boraxin waterat g0.to giveo-hydroxyamides in 65-85voyield. In somecasesadditionof a traceof KCN can increasethe yield. NA,BAq' 80'}

RCHCN |

65-85qo

OH

RCHCONH. I

OH

rJ. Jammot,R. Pascal, andA. commeyras, Tetrahedron Letters,30, 563(19g9).

OH -ccH3 I

ct{. 1

-..i (1989).

I ,.udationof hydroquinones I ( I u'ith sodium periodate is the most critical e .1m()unt o o i u \ r l i t v f N a I O oi n o r g a n i c lc.. than 15 minutes. . r . , : t l e s r6s 4, ( 1 9 8 9 ) . f r t ) ( . H . ) . 1 ( l ) , L 4 ,2 8 4 . rluccr thesesubstratesto P-

Sodiumtetracarbonylhydridoferrate, Na- [HFe(CO).]- (l). ArNo2-"> ArNHz.t Na.[HFe(co)o]- is a known reducingagent in a basic medium.However,the bis(triphenylphosphine)imine (ppN-) saltof HFe(co)a-r in combinationwith a strongBronstedacid (TFA) is also a reducingagent,particularlyfor nitroarenes,even in the presenceof aldehydesor acid halides. Ja'' 5i CuHrNO, + PpN-[HFe(COynl-

C6H5NH2

'P. L. Gaus,S. W. Gerritz,and P. M. Jefries,Tetrahedron Letters,29,50g3 (l9gg). : M. Y. Darensbourg, D. J. Darensbourg, andH. L. C. Barros,Inorg.Chem.,17(Zg7) ( 1978). Sodiumtungstate,NarWOo. oxidation of sec-aminesto nitrones. In the presenceof this tungstate, hydrogenperoxideoxidizessecondaryaminesto nitrones.r &q, cH,oH

CH3(CHr)3N(CHJ,CH, #* H

OH I

. c'.H.ooc&cooc'Hr

. (,:crrr.Leuers,507(1988)

6rw

CH,(CH'),Ii:CH(CH,),CH3 -"1

o- . + | l 7a-114

N H

cH,

-T^an, |

|

o-

H. Mitsui, S. Zenki, T. Shiota,and S.-L Murahashi,J.C.S. Chem C o m m . , 8 7 4( 1 9 8 4 ) ; Org. Syn., submitted(1988).

296

Squaric acid

(f )' Sorbic acid (2,4-Hexadienoicacid), CH:CH:CHCH:CHCOOH dianion (2) of The acids.t Pentadienyl hydrory acids;7-hydroxy-2,4-dienoic acids (3) hydroxy pentadienyl 1 reactswith carbonyl compoundsto afford either Reaction conditions. the reaction acids(4), dependingon or 7-hydroxy-2,4-dienoic

N-Sutfinyl-p-toluenesulfonamide.Ts\:S I ntramolecular cycl ization of ll -tosvl rated aldehydesinto N-tosyliminiumcoo to homoallylicamines. cyclization

COOH

"+*

1uN(c'H'\' l,r^,-'-;"1 ,

"I*."

nJ..1^[ \G/

t

ur* | t.,",I.-o, ro"

+

'i";fiz-'z-*o 4

o '*

"r)'-=/"-""t,

l- ? f,", ^^^.:l gl.n/#f-cooHl CH:cH, J

L

ry t

H' l clt,

' M. J. Melnick,A. J. Freyer,and S. M. l'lcro

t

l'" q

9.H5

*r|/--(\AcH, COOH 6 which graduallyrearof 2 with a substitutedenoneaffordsinitially a 1,4-1-adduct, (6). rangesto a 1,4-ct-adduct J'C'S'PerkinI'2797(1988)' rP. Ballester, andR' Mestres' A. Costa'A. Garcia-Raso' Squaricacid. 1,4-Benzoquinones(13,284).Fulldetailsoftheuseofadialkylsquaratefor are now available'The route to highly substitutedbenzoquinones a regioselective comparableto allerginicity report includesa note of caution:Theseestersshow that of the activeprincipalof poisonivy'' S' L' Xu' S' Patil'andH' W' Moore' I L. D. Foland,J. O. Karlsson' S' T' Perri,R' Schwabe' (1989). 975 111, Am. ioc..

Sulfur. O-Carbonylationof alcohols.t Rer presence of a tertiaryamine(DBU) in Tl with CoHrCH2Br afiords9b esterification

o

DBU'80%) tl RocS . ( D RoH + co + s I

can hardly involve carbonylsulfide.rrhrc at high temperatures(>250"). The lreld beingabout 5Vowith Bu.N and zero rith

T. Hirashima. A. Og T. Mizuno,I. Nishiguchi, 29,4767(1988). Letters,

ts( I'lcooH (1).

k acids.t The dianion(2) of rntudienYlhYdroxYacids(3) rc.ictionconditions.Reaction

o

COOH I H\,)-',-4/-..-/cH,

,

-

TsN:S-O (1). N-Sulfinyl-p-toluenesulfonamide, Intramolecular cycliZation of N-tosylimines.r The reagent convertsunsaturated aldehydesinto N-tosyliminiumcomplexes,which undergo intramolecular to homoallylicamines. cyclization

c-tl/-ou 3

rsrir-sr;-l ' " t L- - ' l | "c),,]'J,ton,r,"\ l-

|]

11

IA

\-f.t-/

|

l\r|--lCH,

CH.

L

I

J

t r"l NHTs H :

NHTs H'l'^

x'""1 \,,,,\CH, Dl{

?-V\ t - t t * t l l CH,

r'rVtV CH, -

(1988). rM. J. Melnick,A. J. Freyer,and S. M. Weinreb,Tetrahedron LeUers,29,3891

Sulfur. of an alcoholwith CO andS in the of alcohols.t Reaction O-Carbonylation presence of a tertiaryamine(DBU) in THF at 80' resultsin a product(1) thaton (2)' The reaction carbonothioates affordsS-benzyl with CoH.CHrBr esterification

o

o tl

il

c'H'cH'Br DBU' 8o7o r RocscH,c^H. , ROCS-(DBU.H). RoH + co + S 12-85qo 1-.rJduct,which graduallYrears .r ( S. Perkin1,2797(1988)'

lhc ure of a dialkYlsquaratefor are now available'The Lurnr)nes Dos allerginicitYcomParableto i i \u. S.Patil'andH' W' Moorc'

I

)

can hardly involve carbonylsulfide,which can be made from CO and S but only at high temperatures(>250'). The yield of 2 is highly dependenton the amine, beingabout 5% with Bu,N and zero with pyridine. Tetrahedron N. Kambe,andN. Sonoda, A. Ogawa, T. Hirashima, T. Mizuno,I. Nishiguchi, T), 4767(1988). Letters,

f(fi

molecularsieveand yieldsare loser. SE presence of a MOM etherby this merlx

I T. Kan, M. Hashimoto, M. Yanagira. and ( I 988).

Tellurium. Tellurobenzaldehyde. This aldehyde (a) is formed in situ by reaction of Te to form the Dielswith (cuHr)rP:CHCuHsandtrappedwith 2,3-dimethylbutadiene reagentto form Wittig the with Alder adduct1. In the absenceof a diene,a reacts stilbene (61.Voyield).

f"'f"'

c.HpH,

(CrHr)rP:CHCuHr+Te

ro5' )

[re:cHCuH,t#

cH,:lt"

"r$.,",

Tetrabutylammonium(tricarbonyhitoo crystals,m.p. 56". The salt is prepare NaNO, and with BurNBr in H,O ar li'. Alkylation of allylic carbonotes.t I the alkylationof allyliccarbonates\r'itht reactionoccursselectivelyat the carbo retentionof configurationof the doublc of configuration,possiblyby two consd

1 CH"' rG. EikerandR. Hock,Angew.Chem.Int. Ed''28' 179(1989)'

l. co. THF

|

cH,:cHC-oco.c.H. ' l l

t

N€H(CGJ'A p a

I

(1)' Telluroniumylides,Bu,Te= CHY (Y = COOCH.' COC6H.'or CN) preparation (.f., 12, 159-160). cyanomethyldibutyltelluroniumchloride bromide(Y: COC6H5)are preparedby (Y = CN) and phenacyldibutyltelluronium respectively'followed by CuHrCOCHrBr, and CICHzCN with reactionof BurTe KOC(CHr)r. with reactionof the salts give wittig reactions.t Theseylidesundergowittig reactionwith aldehydesto reactions, two latter of the case the In nitriles. or ketones, a,p-unsaturatedesters, the ElZratio is I2-I24:1. It is more convenientto carry out this reactiondirectly or with BurTe and the aromatic aldehydeplus XCH,COOCH3, XCH'COC.H" the than 907o) (usually about yields gives higher reaction xcHrcN. This one-pot two-stepreactionthrough the telluroniumsalts' THF,

+ BurTeandXCrIY ;i RC5HICHo

nC.u.CH:CHY

(1988)' rX. Huang,L. Xie, andH. Wu,t' Org.,53,4862 Tetrabutylammoniumfluoride-Hexamethylphosphorictriamide, Bu4NF-HMPT. Clea:vageof SEM etherc.t (Trimethylsilyl)ethoxymethyl (SEM) ethers are I' hour cleavedby BuaNFin combination with HMPT and 4-A molecular sievesin of the absence in the hours 15 requires reaction yield. The at 100oin 90-98Vo 4n

CH,

9H'

I CHt:QtlQ-O{ I

cH.

oco2cH3 CuHs,r.-

CH, _ I ocorcH3 .-t, NaCH(COOCH,\ 78%

('13Voee\

,,\.,.2

r7l

Y. Xu and B. Zhou, J. Org.,52,974(l98a

Tetrabutvhmmonium (tricarbonvlnitrosvl)ferrate

molecularsieveand yieldsare lower. SEM etherscan be cleavedselectivelyin the presenceof a MOM ether by this method. I T . K a n , M . H a s h i m o t o , M . Y a n a g i y a , a n d H . S h i r a h a m a , T e t r a h e d r o nL e t t e r s , 2 9 , 5 4 1 7

( I e88).

is i.rrmed in situ by reactionof Te rneth\lbutadieneto form the Diels1;'. rrith the Wittig reagentto form

_j_c&r x_,it'!n'^.. ::t

cH,-.,-t ll i_ cH-crH5

-e (

I

BuoN[Fe(CO.)NO](1), yellow Tetrabutylammonium(tricarbonylnitrosyl)ferrate, crystals,m.p. 56". The salt is preparedby reactionof Fe(CO).in benzenewith NaNO, and with Bu,,NBrin H,O at 25'. Alkylation of allylic carbonates.t In an atmosphereof CO, this saltcatalyzes the alkylationof allyliccarbonateswith the sodiumanion of diethylmalonate.The reactionoccursselectivelyat the carbon substitutedby the leaving group with retentionof configurationof the doublebond. The reactioninvolvesnet retention of configuration,possiblyby two consecutiveSx2reactions.

CH" 1989).

CH,

:lt COC.H.,or CN) (1). n:crhrldibutyltelluronium chloride bY are PrePared nrJc tY: COCoHs) by followed respectively, ll.Br, 0(

QH, + (cH,)rc:cHcHr(coocrH5), CHr: g11a-cH(CoocrH5), 92:8 cH.

l.rt:rgreactionwith aldehydesto give rhc .'rie of the lattertwo reactions. ir'ti'rr,coffYout this reactiondirectly \( tt.coocH3, xcHrcoc6H5, of rrc.J: (usuallyabout 907o)than the L\

'

i+

l

-

75%

oco2cH3 cuHs

THF

'!\\

r RC^H,CH:CHY

I, CO, THF

t "

NacH(COOC.H.L ------------:--: CH,:CHC-OCO,C,H. '18% l

-r."

, I

cH(coocrH5),

CH,

6corcH,

I' NacH(coocH'L t

(731oee) l

CuHs _r.-

*

I

CuHt',r1..CH,

CH,

'

*

eH(coocu.)2 locphoric triamide, Bu4NF-HMPT. [\.rcthoxymethyl(SEM) ethersare I ,n,l -l-A molecularsievesin t hour !rc. 15 hours in the absenceof the

(73% ee)

9j:7

I Y. Xu and B. Zhou, l. Org.,52,974(1987);ibid.,53,4419(1988).

l

cH(coocq), ('t39oee)

300

Tetrakis(triphenylphosphine)palladiun(0)

TetrachlorophthalicanhYdride. This conversioncan be effectedinT0-90voyield RtcooH.l RrcoNHRr ---> water or of a by tetrachloro-or tetrafluorophthalicanhydridein the absenceof Conversionof solventin a melt at 135-170".This reactiondoesnot affectesters' with tetrafluoronitriles to carboxylicacidscan be effectedby a similar reaction yield. 60-85Vo in days 4-6 135-180'for at acid or tetrachlorophthalic Letters' andG. w. Gribble,Tetruhedfon rJ. T. Eaton,W. D. Rounds,J. H. Urbanowicz, (1988). 29,6s53,65s7

(TCA). 2,6,9,l0-Tetracyanoanthracene Diels-Alder reactions,t Diels-Alder reactionsbetweenelecPhotosensitiZed But in tron-rich dienesand electron-richdienophilesare generallyunproductive' reain occur can cycloaddition this the presenceof TCA or dicyanonaphthalene ,onubl"yield.Thusl,3-cyclohexadieneundergoes[4+2]cycloadditionwithpclol2.2.2foct-2-enewith retenmethylstyreneto form endo -6-methyl-5-phenylbicy tion of the styreneconfiguration'

a\\^,Jffin, /ht"'

C.H,CH:CHCH'* V

P1

MoMo

o\-.,'4,

(c,H,),NfifttlYV o *2&

Cyclizative Heck coupling. Thrs rc of c,B-unsaturatedcarbonylcompound

a>a\acoocHj |

i

\,A,

l

i

l

.

/ coocH3

*;s

-

-

I

n

.-\-->-

. ll)---l-ctt, + 12+2l I

cis CuH,

trans CuH, SlVo lVo

trans cis

Example:

617o

57o l07o

I D. Hartsoughand G B. Schuster, l. Org.,54' 3 (1989).

Tetrakis(triphenylphosphine)palladium(0)' I on deprotonatton Intramileculir arytation. Aromatic substratessuch as (NaH)furnishstabilizedenolatesthatundergointramoleculararylationwhenheated

z, z'

f'^fl \o,''ry(l\^rn^ 4a-6s% \,ry

VariousalkenylethersundergoHec\ of a Pd(0) catalystto form cyclic ethen zopyrans.l

."r-rfg

,-".*A, lCH,

\Z!.(cH)"

1@,2'=CN, COOR,C0R)'n=l'2

n,?,*

2

atl40"inthepresenceofaPd(0)catalysttogivebenzo-fused,five.orsix-membered CH''' rines.Yields are poor when Z (or Z') is H or

Aao-^

/ il

|

(Y = COOCH3)

Ts

PdrP(c.H,)rr.,HoAc, A

-

/

Ts. -Ts

Ts

$q'

t/

t"o)

crL cH, Ts

Ts I /N\

t

I

l

fc4\cH, OAc

a*\ t l

+ 63%

cH,

3-Aza-Cope rearrangement.l This rs by Pd(0) and a strongprotic acid, parrior fonic acid. This isomerizationis involved iminesfrom allylamineswith carbonvlcq

o)C6HsNH ^...ft"'. "q{ Lcr

(Y

cH,

lcx,r

lCH,:g116",Sn(IV)l #ft+

CH,:6116n,i"*

Example:

C6H5CHO+ CH'\4\/OH

P{lfL

'

OH

=,.,u,,Xilo" 2 (2R, 3R, 98Voee)

oH

RcHo

I

u,c]

?H

cun, * H,cfcuH,

CH,

CH, 49:51

310

Tin(II) chloride-Chlorotrimethylsilane

of I r3-dienes.2 These1,4-endoperoxides D eorygenationof 1,4-endoperoxides are reconvertedto 1,3-dienesby Snclr.

quH,

C^H.

io l l

t"-

3"'h

l +

v,o I

CuHt

C.H.

A 2 I + l

vIo

k

CuH,

CuHt l5Vo

fu", 116

(33Vo)

?,"' 4-\

v*'v c.H,

' T. Mukaiyama, K. Wariishi.Y. Sarto.I ( 1e88).

cuH,

rY. Masuyama, J. P. Takahara,and Y. Kurusu,Am. !oc.,110,4473(1988). 2 S. Kohmoto, S. Kasai,M. Yamamoto,and K. Yamada,Chem.Letters,1477(1988).

Tin(II) chloride-Chlorotrimethylsilane. Aldol-type reaction of acetals with alkenes, Mildly activated alkenes can undergoaddition reactionswith acetalsin the presenceof ClSi(CHr)sand SnClz, as in the reactionwith dihydropyran.However, the correspondingreactionwith styrenerequiresa full equivalentof ClSi(CHr),and a catalyticamountof SnCl,for a satisfactoryyield.

A I \o/

c6H5cH(ocH)2 -- c.ll;

crs(cH,)I ffCuH, C.H,CH(OCH,), * 84% | | ll+ \oAo." |

?'",

2

cl + I + ClSi(CHrt CTHTCH:CH, #

ocH"

CrHr$CrU,

Thesereactionsmay involve the activespeciesa.

Tin(I9 chloride. Regio selec tive O -debenzylatia is the most effectivefor this readrc BzlO BzlO BzlO

Bzl( Bzl( -cHac\.2s' ltr

OBzl OBzl OBzl

hr.) 1 TiCL(O.75 1 SnCl.(7 hr.) 2 SnClo ;OBzl fOBzl LOBzI

;OBd FOH t-OBd

SnClo

86%

ricl

6E%

requiresat least three groupscape order of complexationis priman > 2- O -Organosily I g lycosidcs; CI densationof furanosidesand orgnn furanosides.Thus the reactionof lh

Tin(lV) chloride

Ecnes.zThese1,4-endoperoxides

+ (cHr),SiocH, t' ceHscHaot"' c6H5cH(ocH:)z -cl

CuHt

.

311

(.'Jl

O

v

f .ocH;l | ^-./"---'l RCH=CHCO2CHy.| O uratedesterscan be effectedby reactro equiv.) catalyzedby zinc powder. Thrs heteroarylaldehydes.

o /--"'

t

+ p-BTC.H.CHO + Bu,Sb-ft,

l

RCHO + BCHTCOOCH,-! R = C.H, R = CHI(CHJs

n-BrCrHi

I Y. Shen,B. Yang,andG. yuan..l.C.S CiL

(synlanti= 7l:29) rY.-2. Huang,C. Chen,and Y. Shen,J.C.S.Perkin1,2855(1988).

Tributylphosphine-Zinc. Wittig-like reaction.t The reacrron promotedby Bu.P (1 equiv.)and Zn rl

Trialkyltin hydrides. Cyclopropropylmethyl radicals.r Generation of a radical center adjacent to a cyclopropane can result in ring opening of the cyclopropylmethyl system. This reaction can be used to convert allylic cyclohexenolsto alkylcyclohexenes,as shown for conversion of I into 3 via the phenyl selenide 2. When the cyclopropyl ring is

I Y. Shen,Y. Xin, andJ. Zhao,Terrahedro I

SeCuHt

OH

* .cr'i'lrjilY' A ;;ilrf,l: a\ -cr=*= '#9., +' ?''\4s,.,, :?J.-.,,t;.i vrr3

vrr3

cH,

r

I

CH3(CH),'CHO+ BrCtlCOOC{ -

cH,

cH,

2

3

ring expansionis a competing,but minor, pathway fusedonto a cyclopentane, (equationI). Photolysisof a benzoateor bromiderather than a selenidecan also

Tributylstibine,Bu.Sb. a,p-Unsaturated nitriles.t The rce and Bu.Sb (1 equiv.) resultsin theseunr /rcrs-isomers. n-C'H,,CHO+ CICILCN+ BurSb+ ncl tDla

SeCuH, BusSnH ,tv, 0'

+

86co

+

isomeric cyclohexene

8 4 :1 6

be usedto generatethe radical.The Simmons-Smithreagentis suitablefor cyclocan be controlledby the hydroxyl group. propanationsincethe stereochemistry Intramolecularcyclopropanation(1i1,52) is also useful. The advantageof this systemis the regio- and stereoselectivity. I D. L. J. CliveandS. Daigneault, (1989). l.C.S.Chem.Comm.,332

i Y.-2.Huang,Y. Shen,andC.

Chen.Srn C

Tributyltin hydride. Regioselective cleavoge of gcll.a{ methyl)cyclopropane is cleavedby Bu.So -CH"Br ' v

n

F F

BrJ.tl

^Ds.cJ{

Tributyltin hydride

() + (Bu'SbBr)P f^t", cH, _ RCH=CHCO2CHy,| Conversionof aldehydesto (E)-c,B-unsaturatedesterscan be effectedby reactionwith methyl bromoacetateand Bu,As (1 equiv.) catalyzedby zinc powder. This reaction proceedswith alkyl, aryl, and heteroarvlaldehvdes.

Tlibutylphosphine-Zinc. wittig-like reaction.t The reactionof an aldehydewith methylbromoacetate promotedby BurP (l equiv.)andzn (1 equiv.)provideso,B-unsaturated esters.

i .: :.rdrcalcenter adjacent to ;l,,rr()pvlmethylsYstem.This r .r.i.r lcvclohexenes,as shown \\ hrn the cycloProPYlring is

BulR Zn

g--+ CH3(CHr),.CHO + BrCtlCOOCq

Cq(CrD,oCH9CgCOOCn,

I Y. Shen,Y. Xin, and J. Zhao, (1988). Tetrahedron Leuers,29,6119 rh..-H. i

:-+

l

.,,\.,

l

CH"-l I .H"\-'4cHcL

CH,

3 n : \ t r n g . b u t m i n o r ,P a t h w a y t!r.(r thana selenidecan also

-

Tributylstibine,Bu.Sb. a,p-unsaturatednitriles.t The reactionof chloroacetonitrilewith aldehydes and Bu.Sb (l equiv.) resultsin theseunsaturatednitriles as a mixture of crs-and /rdrrs-isomers. n-C'H,,CHO+ CICHTCN + BurSb+ n-CrH,,CH:CHCN [+ BurSbCl,+ BurSb(OH)r] = 62:38) (translcis ' Y.-2.Huang,Y. Shen,andC. Chen,Syn. (1989). Comm.,19,83

isomeric cYclohexene

.-1 t6 I

h :..,rcnt is suitablefor cycle r' .r.i bl the hydroxYlgrouP. sr':,r, The advantageof thb ::' 'l9li9).

Tributyltin hydride. Regioselective cleavage of gem-difluoropropanes, 1,1-Difluoro-2-(bromomethyl)cyclopropane is cleavedby Bu.SnH/AIBN to 3,3-difluoro-1-butene as the ''CHrBr X F F

BurSnH

^'BN'c6H' ) cHrcFrcH:cH,

326

TributYltinhYdride

comcanbe usedto obtain(E)-difluoroallylic onlyproduct.rThisradicalreaction of the C'-C' bond'2 cleavage preferential io,i"i, o".".se of n "?V:" -

X

l

'

o

2-Deoxy sugars.a Reductiono bY rearraq Bu,SnHis accomPanied center.The migrationis cri-select br thr Bu.SnH is not accomPanied

CH, z *n-HexcH'cF'cH:cHcH: ' o

(E)

rnr i

-.&

qHCHrcHrC6H5 |

{

F

OAc

cH'cF'cH:cHcH2cH'c6H5 (E)

;

ToAc

F

In reactionswith atom tray{er cyclizations'3 Intramolecular l,S'hydrogen canundergo (14' 313.)'an originalvinyl radical low concentratlon,of tt'" iin nio"a" bond' which then " ne* taAicutfrom a C-H a l,5-hydrogenshift t" p'"l'i"t I)' undergoescyclization(equation E---,8

Bu'sncl.ArBN NaCNBHT' (cHt)rcoH

I fl) cH.oI - _/cHnrA6U,

FO

A c o (

OAc

AcO

Allyl radical cYclization.' A but can undergocyclizationu'rth I

)

HzC.r \ ,

/ \,/

CH,

G = coocHJ

) u

.",tn.i H2

fHCHrBr

(

l

\

""t * ABli

r

r

cH,oocncoocH3 (E or Z)

cH3ooc

""1

X

cH3O \

(

clocll

-CH,

CH: = 18:82) (cisttrans

c ExamPle:

om /

,),._)

v\,,cooc,H5

?cHrC6H5 cHrcoocrH5 s6%

\J = l:2'5) (cisltrans

^

/

;#("

Tributylrin hydride

com) r'rr.un(E)-difluoroallylic - (

bond.l

327

2-Deoxysugars.a Reductionof acetylatedor benzoylated glycosylhalideswith Bu.SnHis accompanied by rearrangement of the estergroupat c, to the anomeric center.The migrationis crs-selective. Reductionof 6- or 4-iodoglucosyl iodide by Bu.SnH is not accompaniedby this rearrangement.

HeTCH.CFTCH:CHCH: (E)

,zOAc

)"'n. -S* s2% o.o

A.o' {

\__/ / AcO OAc

3F,CH:CHCH2CH2C6H5 (E) r.cli:ations.3

ft'

In reactions with

)rrirnul vinyl radicalcan undergo Ir,r:'. .r C-H bond, which then

6OAc

Bu.SnH,

FO

o.o.( AcO

/

FO

\

\

onc

r)

AcO

f:'

t'-,*-*o.o..(

)

OAc

Y AcO

foo.

Allyl radical cyclization.s Allylic radicalsare lessreactivethan vinyl ones. but can undergocyclizationwith Bu,SnH/AIBN. ECrr Y I /

.//CHCHTBt,ornn,

Y \l

AIBN ----'

\-/

cH"oocncoocH,

rr,-""r:/\.j ".1

(E or Z)

cH3ooc coocH3

coocH3 5 9 : 3 1: 9

X '"1"X.",

f":"u cH,ooc\/\-/ cH3ooc

(cisltrans= 18:82)

CHrBr

z I)C.H5

cH3ooc coocH3

H ,CH:CH,

ay,

---------) | ) 86%| \.-.1--_1 .COOCH3 H /

cH3ooc ( 2 . 4 :l )

Tributyltin hydride

CH,BT

"o^l\

ov\.tH'y'" (-\,

;

Acyl radicals.t Tributyltin hrdndr eslen. r acylradicalsfrom phenylselenol or phenylthiolestersfor acyl radicalsfo

CH:CH,

(-,f.t-/ H (0/a= 5: 1)

B''

c

z^/4.

lt . i r l I ll anti-Radicalelimination.6 Reactionof nitroalkeneswith lithium benzenethiolate and then with aqueousformaldehydeprovides anti-1-phenylthio-B-nitro alcohols(1), which undergo radical elimination (Bu.SnH, AIBN, 110') to (E)allylic alcohols.

B-"r91I,^^ CHrTO' r)c6H,sLi lloo, -)C:Cf ,H AIBN, z)Hcno,CHr:rA.zOH -.,*CH'CH:CHNQT-.'* H-"-"-C'LOH | sc6H5 2 ( E l Z= 9 : r ) = 87:l3) | (antilstn RI --->RCN,1 One step required in a recent synthesisof 9,11-dehydrodigiexchange toxigenin(3) is an iodide/cyanideexchangewith the steroid 1. Direct yteld' 40Vo only ,.q,iir", protectionof the 14p-hydroxylgroup and proceedsin Bu.SnCl, by The exctrangecan be achievedby a free-radicalreaction initiated NaCNBH..and AIBN in82VoYield'

\./

-cos"c.tl

Z*coS€c6tL t t l

\A,S.-coocH.'

Acylation of isoquinolincs.t A mrr chlond at -78'with a 3-halopropionll quinolinesin 80-95Voyield (c/.. Li. ll with Bu,SnH/AIBN to furnish benzorr

o tl

+ CICCH.C}IJ

CN r-BuNC,NaBHTCN Bu,SnCl,AIBN 825.

Acylamino cyclization.t' Th€ ind by radicalcyclizatimt beensynthesized 2m acid,to providethe indolizidinones includedremovalof the keto groupbr c reagent(97%) followed by desulfunee

Tributyltin hydride

C H : CH, CH.,

.---1,,^) l

l

t'--,rf\.r'

329

Acyl radicals.s Tributyltin hydride in combinationwith AIBN can generare acylradicalsfrom phenylselenol esters,whichare a bettersourcethanacylchlorides or phenylthiolestersfor acyl radicalsfor intramolecularcyclization.

H ;r,r=5:1)

l l l o.:.icneswith lithium benzeneor :J cs anli-J-phenylthio-B-nitro t t s uS n H , A I B N , 1 1 0 ' )t o ( E ) -

\_/

I\aor.au",

H

,i:.,l,l;tfl_ - *E2% ' t

t t

Y)/ = (tro^tri? 62:38)

", cH,-..^ i'j ^./H -------------> u:u -'+ -c4on H/

4?cosecoH'

z>/\

\A-=-coocH3-(Af" cH2coocH3

2 (Elz = 99:r)

I . \ n r h e s i so f 9 , 1 l - d e h y d r o d i g i iii .teroid 1. Direct exchange rJ :.r\)ceedsin only 40Voyield. :i.i.tion initiatedby Bu.SnCl,

Acylation of isoquinolines.eA mixtureof an isoquinolineand Bu.SnH reacts at -78o with a 3-halopropionyl chloridein cH,cl, to give N-acyl-l,2-dihydroisoquinolinesin 80-95% yierd (c/., 13, l0). Thesecan undergoradical cycrization with Bu.SnH/AIBN to furnish benzoindolizidin-3_ones.

z\.'^\

\'\

CH. ,CN

R+ ll \r\zN

fr

B^::s:I'

.,4.

"''! | + CICCH.CH,I ' R* ll 8s-esqo \/\/,Y

/-\L4

L - l l l ) /'\,4< I on

/.r

|

|

o l5-8O%

BursnH,AIBN J

,, -ot \_/

Fo Acylamino cyclization.t, The indolizidinearkaloid( (3) has )-swainsonine beensynthesized by radicalcyclizationof the acylamineI, derivedfrom o-tartaric acid, to providethe indolizidinones 2 in Tlvo yield.conversionto the alkaloid(3) includedremovalof the keto group by conversionto the thiolactam by Lawesson,s reagent(97vo)followedby desulfurizationwith Raneynickel (96% yield).

Tributyllin hydride

(cHr)rSi\€r"rrJo. | | \-*{

*a"tt

OAc

)"'oe'c

BqSnH, AIBN c.H., A 't1%

'

'

Bo'Salt AIBN

SeC.H,

."OAc

)

O.,CHTCH:CHC6Hs I 2 ( - 1: l )

G" 3 p-glycosideshas relied heavily on the S-Glycosides.ttThe constructionof anomeric effect (equatorial cracetoxy substituent). A recent approach relies on generationof a radical at an alkoxy-substitutedanomericposition. The precursors (I). The samestrategycan be appliedto if; .un be obtainedas shownin equation p-linked disaccharides. constructionof

*-to'tt SeC.tl

(II)

ozCHzCH:cHc.4 4

1)Lrwessm'sregmt(62%) Bzlol

BZIOI

.ur4;,,fL-\ naoL t

BzlO

il'''#{:'i13?,n'"'*' , tt?e{\,*", \ ^-O

-

BzlO

i"r.

I nu,snn,elBr't --o'- | c.uPtt' loe |

Thioimidates can undergo similar rrl Deamination of RNH..B A new mctl amines(1.)involvesconversionto an at(f, verted to the hydrocarbonby Bu.SnH ro isfactoryin the deaminationof benzl'lamn of simplealkylamines.

.

ocH3 Bdo 2 (Plrr= 12:r) l with Bu$nH cyclization of selenoimiilates.D Reaction oi the selenoimidate (AIBN)generatesanimidoylradicalthatcyclizestothenitrile2andtheimine3 on nitrogenis changed of u.h.on,unone. Only 3 is oitained if the benzylsubstituent toanalkylgroup.Thereactionfollowsadiffer,:ntcoursewhenanN-tolylsele. noimidate (4) is the starting imine (equation I)'

l) cr! 2)socL

N,

r

R = CeHsCHz = CcHr:-c = CrHn-z

) C.H4:S

l

O I

Stereoselective radical cyclizltia Sridartahave noted transannularefiecrs< theseoctadienes(equationI). Thus rxlc spondingketone (3) is highly rraru-sckxt of the monosubstituteddiene 5. Cvclizat

Tributyltin hydride

331

*t""

SeCoH,

#

BursnH, AIBN

o..CHzCH:CHCbH5 2 (-l:l)

CN

,.CII.CH:CHc6H5 2 (s0%)

>ris has relied heavily on the tt , .-\ recentapproachrelieson tr,:Idnc position.The precursors I ..:nrcstrategycanbe appliedto

3 (50Vo)

CH, *'-TolYl

tl TD (rSECUH'

\Ao-cH,cH:GHC.H,

BzlO-r

^I J Z I^,l--\-----q U \ \ scH, Bz ro L \ \ urto 6c", I ABN ^-- | su.snH, o'to I c.tt.cx., lo'

l) c.Hpocl

BzlO--r

.^/rl--.-q IJZIU \ BzroL

Thioimidatescan undergosimilar radicalcyclization. Deaminationof RNH,.8 A new methodfor reductivedeaminationof primary amines(1) involvesconversionto an aromaticimidoyl chloride(2), which is converted to the hydrocarbonby Bu.SnH and AIBN (10, 412-413).Yields are satisfactoryin the deaminationof benzylamine,but are only moderatein the reaction of simplealkylamines.

RNH, 4!-.} \

o c H, \ \

BzlO 2 (Bls= 12.r)

l with BurSnH rhc.elenoimidate s :.' rhe nitrile2 and the imine3 ltr.lr!ueot on nitrogenis changed n: iourse when an N-tolvl sele-

1

R = cctLCHz = cF.nr-c - QH,,-z

C.Hr$:rVn

B'rsnH'AlBN,

RH

+ C6tIsCN

l

cl 2

G2%) 6lqd (3E%)

(Bz%) (ffi%) (37%)

Stereoselective radical cyclization ol 1,S-cyclooctadienes. Winkler and Sridarrahave noted transannulareffectson the stereochemistry of cyclizationof theseoctadienes(equationI). Thus radical cyclizationof crs-l and of the correspondingketone (3) is highly trans-selectiveand is more trans-selective than that of the monosubstituteddiene 5. Cyclizationof a 3,S-disubstituted cycloocteneis

Tributyltin hydride

2 (99:l trans) 2 (5: I trans)

cis-1 trans-l

A

o

p

.\"

8 D. L. Bogerand R. J. Mathvink.rDtd..fl.. e R. Yamaguchi,T. Hamasaki,and K. Udm r0J. M. Dener. D. J. Hart. and S. Ramesb.J " D. Kahne, D. Yang, J. J. Lim, R. Millcr. r '2M. D. Bachiand D. Denenmark . ibid..lll '3T. Wirth and C. Riichardt,Chimia.{1. ll0 'a J. D. Winkler and V. Sridar, TetrahedronL 1708(1986). 's M. D. Bachi and E. Bosch,J. Org.. {. l1t

Tributyltin hydride-Tributylphosplir r Reduction of carbonyl compl*.r duced to chlorohydrins by Bu.SnH in < HMPT.

V",tI \+

I I. Shibata,T. Suzuki,A. Baba. and H \llt

trans-4(95:5) Tributyltin hydride-Triethylborrnc. Deoxygenation of alcohols.r Dithr sponding alkane on treatment with BUS benzene.

(7:l) trans-6

5

S

can be correlatedwith The observedtrans-selectivity completelytrans-selective. rings' transannulareffectsin unsaturatedeight-membered acid derivativesof 4-phenylof thionocarbonic reaction The Thionolactones.B as the major product thionolactones provide (AIBN) can BurSnH with 3-butenol via a radicalcyclization.

tl

ROCSCH

Butyrolactones.2 The samereagent homopropargylicor homoallylicalcohob

S

fir r c6H5A.

nu,snH,,n*N BdJ^ c'H"A

./ocscH3 #

\ \-J l " + B u . S n S C H ,

lW. R. Dolbier,Jr., B. H. Al.Sader,S' F. Sellers,and H. Koroniak'Am, Soc.'103'2138 (1e81). t i, Morikawa, M. Uejima, and Y. Kobayashi,Chem' Letters,1407(1988)' 3 D. P. Curran,D. Kim, H. T. Liu, and W. Shen,Am' Soc',110'5900(1988)' a B. Giese,s. Gilges,K. S. Groninger,c. Lamberth,and T. vlitzel,Ann.,615 (1988);B. Gieseand K. S. Grdninget,Org. Syn.,submitted(1988)' r G. Storkand M. E. Reynolds,Am. \oc.,110,6911(1988)' 6 A. Kamimuraand N. Ono, t.C.S' Chem.Comm', 1278(1988)' 7 A. R. Daniewski,M. M. Kabat,M. Masnyk,J. wicha, w. wojciechowska,andH. Duddeck. l. Org.,53, 4855(1988).

c^H.scH" f :5

'li 'Ld

p't tnt""'tctJ'"' ; -Bu"SnscH' L

cr"r-,

fl scu"

c2H:\cE

( P'.-; a \-o

I

\-o

I K. Nozaki. K. Oshima,and K. Utimoto. Ic ' ldem, ibid.,29,6127(1988).

Triburyltin hydride-Triethylbonne

ED. L. Boger and R. J. Mathvink, ibid.,53,3377 (1,988). 'R. Yamaguchi,T. Hamasaki,and K. Utimoro, Chem.Letters,913(1988). r0J. M. Dener, D. J. Hart, and S. Ramesh,J. Org., 53,6022(1988). 'r D. Kahne,D. Yang,J. J. Lim, R. Miller, and E. Paguaga, Am. Soc.,ffO,8716 (1988). '' M. D. Bachiand D. Denenmark,ibid.,lll, 1886(1989). 'r T. Wirth and C. Riichardt, Chimia, 42,230 (1988). 'oJ. D. Winkler and V. Sidar, TetahedronLetters,29,6219(1988);Idem, Am. Soc.,l0E, 1708(1986). 15M. D. Bachiand E. Bosch,J. Org.,54, 1234(1989).

H I w t

o I

Tributyltin hydride-Tributylphosphine oxide. Reduction of carbonyl compounds.t ct-Chloro aldehydes or ketones are reduced to chlorohydrins by Bu3SnH in combination with I equiv. of Bu.PO or HMPT.

H

I I. Shibata,T. Suzuki,A. Baba,and H. Matsuda,,/.C.S. Chem.Comm.,882(1988).

i

l9


( c i s ,1 2 : 1 )

,r*f.u*c"r,u ln=3 = 5 =6

c.H.ooc CHr._/

(

(

)(cHr)"

) (cHrL_,

457o 317o 3l7o

o

CH;

6

l4Vo 78Vo ffi%o

'"'X, #d,='"'2ArCN. This Ni(0) catalu KCN in HMPT or CH.CN at 6{f . Cou! to only a slightextent.l

cl ,\.oc

f

3

il

N(orHxPr *xcN s ,l q6

'

\,,/

I Y. Sakakibara. F.Okuda,A. Shimobavas Bult.Chem.Soc.lapan,6l' 1985(l9BE)

Ttityl chloride (triphenylmethyl chlond N-Tritylamino acids. Direct reac videsN-trityl derivativesin low yield. A reactionof trimethylsilylestersof S-rn in refluxing chloroform, which prorrdc hydror.r yield. Trimethylsilyl-protected

conditions.' 4-Polystyryltritylamino acids can bt methylsilylestersof amino acids.:Thc

Trityl chloride (ftiphenylmethytchloride)

359

by UV photolysisat 40'or by dibenzoylperoxideat 50".Yieldsof RH areessentially quantitative. It is as efficientas Bu.SnH for initiation of intermolecularor intramolecular radicalreactionswith alkenes.3 I, AIBN,

. R.Sio

70-eo" , C6HTCH2CH2CN

CuH,,I + CHr:gggtr1

r, ArBr

CHr:6g,.";,e,l9i 3

9H'

1A1--

\J

93Vo 1) CFTCOOH 2) NH,

\-,J ZVo

rC. Chatgilialoglu, D. Griller,andM. Lesage, J. Org.,53.3641 (1988). 2Preparation:H.BiirgerandW.J.Kilian,"/. Organometal.Chem.,lB,Zgg(1969). r B. Giese,B. Kopping,andC. Chatgilialoglx, Tetrahedron Letters,30,68l (19g9). Ttis(triphenylphosphine)nickel(0). This Ni(0) complexcan be generatedin situby reductionof Br,Ni[P(CoH,),]with Zn-p(CoH.).. Ar{l --->ArCN. This Ni(0) catalysteffectscyanationof aryl chlorideswith KCN in HMPT or CH.CN at 60'. Couplingof aryl chloridesto biphenylsoccurs to only a slightextent.l

.omplex with TDA-1 in ether trp6rationof the solvent.The or cyclohexane. na:rcsolvents, rnnieresreactas regularGrigI re.ictive.The slightdifference )reienceof ketones.The comgrcrrer extentthan a regular

CI y').ocH I ll

Ni(ollrMpr, +KCN

o""'nrlr$fu

quul

\./

I Y. Sakakibara, F.Okuda,A. Shimobayashi, K. Kirino,M. Sakai,N. Uchino,andK. Takagi, Bull. Chem.Soc.Japan,61,1985(1988).

r,:.':. lE, 99 (1970). I a-, ' F Seela,H.-P.Muth, and U. rc (

Reye, Tetrahedron,45, 77l

s Bu,SnHfor reductionof RX The reductionscanbe initiated

Trityl chloride(triphenylmethylchloride). N-Tritylamino acids. Direct reactionof trityl chloridewith amino acidsprovidesN-trityl derivativesin low yield. A superiorroute to thesederivativesinvolves reactionof trimethylsilylestersof N-trimethylsilylamino acidswith trityl chloride in refluxingchloroform,which providesthe N-protectedamino acidsin 88-92% yield. Trimethylsilyl-protected hydroxylor thiol groupsare not cleavedunderthese conditions.l 4-Polystyryltritylamino acids can be preparedin the same way from the trimethylsilylestersof amino acids.2TheseN-protectedamino acidsundergousual

360

TritYl hexachlororntimonrte

couplingreactionswithaminoacidesters,ofteninquantitativeyield.Thepolymeric yield' proi".tiu" group is removedby p-TsOH, HCl, or TFA in 75-90Vo I P.Mamos, Ann', 1083(1988)' andK. Barlos, C. Sanida, andP. Sotiriou'ibid" 1079(1988)' , i. sartos,D. Gatos,I. Kalitsis,D. Papaioannou,

I T. Mukaiyama, P. Leon, and S. Kobal-ahr.

Trityl perchlorate. Addition of silYl enol ertcn rc 4 ditions becauseof the sensitivit;-of dr

Tiityl - Achloride-Tin(Il) l l y l k e t e n e d i t hchloride' ioacetals.Inthepresenceofthesetworeagents,ketene dithioacetals(1)reactwithallylmethyletherstoprovideallyl.substitutedketene and Sncl is an equally dithioacerals(equationI). Th; combinationof clSi(cH),

-"'X cH. (r) H

- i"' ?t"' :fl-*9-! t",^* '

#I *. sH,A.^c4 s / r

c

H

o

(r)

osi(cHr\ + C.HTCH:C}|C

CH,

, 3 ( 9 1: 9 )

effectivecatalystforthissubstitution.Asimilarreactionoflcanbeeffectedwith a,p-unsaturatedortho esters(equationII)'' OCH

(r)1+cH,Jru

O

QH,

tr:l#b'.",oA&tl ts/ cH!

catalyticamountof trityl perchloratclc at Cotend to undergol,Gaddition rrd

rT.Mukaiyama,H.Sugumi,H.Uchiro,andS.Kobayashi,chem'Letters,1291(1988)'

o Trityl hexachloroantimonate,TrSbClu(1)' Reactionofa,p-unsaturatedacetalswithsilylnucleophiles.Thistritylsalt acetal(2) of cinnamaldehyde is an efficientcatalystfor reactionof the dimethyl B-azidoketones'The silyl nucleophilesto form 1'D-unsaturated with successive by the Staudingerreaction'r azidegroup can be reducedto an amino group

9cH' t c6H5

,

.^ocH3' t

N.

9 S R , f c H'l , o o l N's(cH!\ t I ll I ' cuH,c:cH,.+ 85% l_crn,A.,A4crnl - ,- L

A

c,H,A'AAc,H,

H,o P(c6H)',

-#-

NHt

I

cuH,AAAcuu'

tl

/,.,?o ll

|

R/'\/ (R = ,-Bu)

osi(c I

+ C.H,CH ,CH:C

Trityl perchlorrle

a::::.rtiveyield.The polYmertc T \ r n 7 5 - 9 0 %y i e l d . ) : ::rrtr.r. ibid.,1079(1988).

rT. Mukaiyama,P. Leon, and S. Kobayashi,Chem.Letters,1495(1988).

Trityl perchlorate. Addition of silyl enol ethen to o-quinones.l This reaction requires mild conditions because of the sensitivity of these quinones, but can be achieved with a

)! :1.\e two reagents,ketene ketene r,.r :.1eallyl-substituted t( ll t. and SnCLis an equallY

o

(l)

CH"

" l s :- cH,\4=rz")

osi(cHJ3

tl ):-o

ll cH3/'V

oSi(CH3)3

|

r'.ro.

ry + c6H5dH:cHcH3

CH, H

o\

CH,

- - ' J

/

\ _ ,

CuH,

S

CH,

361

3 ( 9 1: 9 )

,rol n.o'

+ '

rlrt'n of 1 can be effected with

on\-

I rcHCoc6H5

"o-{

,"!&,) (1988). h: ( rrcnr.Letters,1291

gH,

4.",

catalyticamountof trityl perchlorate(equationI). o-Quinoneswith a bulky group at Cotend to undergo1,6-additionwith silyl enol ethers.

o

osi(cHJ;

R osi(cH3)l

I nucleophiles. This trityl salt I :,clal (2) of cinnamaldehYde aru:.rtedB-azidoketones.The reaction.t thc Staudinger

).O"

+ cuH'cH'cH:cHCuHs +

o

*),') (R = ,-Bu) -

cH ,I o o \-,,,\-

il

NH"

I

N,s(cx*, | -ss*

cuHl

cH2c6H5

61%

lHlO'

*Yl[-rr"''' Y

O

,.\4A".",

Yo^cH2c6H5 OH

le|

Thityl perchlorate

Aldol reaction betweeno.rp-acetylenicketonesand sityl enol ethers. TrClOo is an efficientcatalystfor 1,2-additionof silyl enol ethersto o,B-acetylenic ketones.2 OSiR3

O

9 CH, OSin,

rrc,o. I ll ,AX. cHrc-C=c-CuHr+C.HrACHrffi c;+, o

l

cu,c-c=c-si(cH3)3

l

-\.

--a.",

osi(cH3)3

r

+ (cHr)rcHCH r-t:CH,

#t

o o H

i l l

-C (cH3)'CHCHTCCH2C I CH,

:

,-CHt

Ultrasound,(((. Diels-Alder reacfions.t Ulu with o-quinones.and also impro obtained in the absenceof a ro pigmentsof Chinesesagerespor exampleis the synthesisof 3. rh reactionof the dieneI *'irh thc gt improvesboth the regioselecrrrr

"YV

CSi(CH3)3

(trarslcis= 65:35) ' Y. Sagawa,S. Kobayashi,and T. Mukaiyama,Chem.Leuers,llli (l9gg). zS. Kobayashi, S. Matsui,and T. Mukaiyama,ibid.,1491(1988).

o

n

\,^t

(

.:

oi'WCH' cH3to CH, c6H6'A, 10 kBar,25" ((t',neaL45o

l5c 7,1{ 16C

o ""\o CH.

Review.2 Ultrasound irradrarr with many organometallic reagent -zinc reagents(64 references;.

' J . L e e a n dJ . K . S n y d e r . , , l m. 5 . r r . _| : R. F. Abdulla,Aldrichim...{cra. !1. _

ol ethers. TrClOo cetrlenicketones.2

Ultrasound,((1. Diels-Alder reactions.t UltrasoundcanpromotesomeDiels-Alder reactions with o-quinones,and also improve regioselectivity. Highestyieldsof adductsare obtained in the absenceof a solvent. This reaction provides a route to some pigmentsof Chinesesageresponsiblefor the biologicalactivityof Dan Shen.An exampleis the synthesisof 3, the acetonideof tanshindiolB. Thus the thermal reactionof the dieneI with the quinone2 gives3 and4 in the ratio 1:1. Sonication improvesboth the regioselectivity and the yield.

-H_

^? f"' "Y^f,

-\^

I

L

A: i5) l!\\ |

-si1cH,;,

| I

\Aol

il ll

-

^"'\A'zcH' -\ : -cH. cHsto

.2

>

1) SiO,,O, 2)DDQ

I

CH, l57o C.Hr, A, l0 kBar,25o 737o ((t.,neat,45o 76Vo

o

q ' ' CH, lro

r

CH

CH, 3

4 1:l 7:l 5:1

Review,2 Ultrasound irradiation improves the rate and the yields of reactions with many organometallic reagents, particularly of organocopper, -lithium, and -zinc reagents (64 references). r J . L e e a n dJ . K . S n y d e rA, m . S o c . , 1 l 1 ,1 5 2 2( 1 9 8 9 ) I R. F. Abdulla,Aldrichim.Acta,21,3l (1988). 363

F(CH,)Si -'

Vanadyl trichloride (Vanadium oxytrichloride)' VOCI. (1)' acids. Oiidative decarboxylation-deoxygenation of 3-hydrorycarhoxylic 1 equiv' with chlorobenzene in heated Theseacidsare convertedinto alkeneswhen [2, 1,8-bis(dimethylamino)naphthalene]' eachof VOCI, and Proton Sponge@

o o H ll

A HO,

|

/"H

x CH;

v6rrs

1 . 2 . c ." H-.\ J c6H,cL^, Bqo

CH3

/ H

o o H ll

X

I-

Ho- Xi.r.rr,.zlt.u

CH;

cH. \ CH,

c^H.. " "\

cw:Nc6H'cH"2

,*%-

/

!H,

__/a^-_ CH,

\_

ascar with Pd[P(C.Hr).1. in couplingof the rinrb I K. Tamao, T. Kakur.\t | lX 98-1 Tetrahedron,39.

Vitamin Bp (H1'droroc Isomerizatioa d qt effectedwith strongba* to opticallyactivealhlrc B,r at 25". Thus clclopc ee. The rearrangemen is more typical.

CH.

Y;;

(1989)' I I. K. MeierandJ. Schwartz, Am. ioc.,111,3069 RCH = CHSiF(CH)z(1). The reagentsareprepared Vinyt(fluorodimethyl)silanes, with copperfluoride' by ieactionof the correspondingvinyl(chloro)silanes much 1,3-Dienes; vinylarenes.rThese fluoro-substitutedalkenylsilanesare iodides vinyl with reactions in coupling more reactivethan trimethyl(vinyl)silanes vimediatedby TASF and a palladiumcatalyst(14, 340-341)' Oddly enough' relonger require and 1 than are slightly lessreactive nyl(difluoromethyl)silanes The actiontimes,and a trifluorosilylgroup is completelyinactivein this coupling. particularly components, couplingproceedswith fetentionof configurationof both Pd cal, TASF

CH.(CH)s-yay'\S(CHJTF* | --7

pur),cH,

#

cHr(cH), _r,ryVr--(cHJ5cll3

CH3(CHJr, ,S(CH3)f + t4 \-'

\:/

lcoCrq

'

_-' ,Yh

.r,(.*L),\_/Crcoctr'

o I H. Su. L. Walder. Z.<J

Vitamin B12(Hydroxocobalaminhydrochloride)

F(cHJ2si

/si(cHr)rF

+ 2IC6H5 ;-

365

cuHrr_rcuH, (ZlE= 4:l)

\()(, (l). ol 3-hydroxycarboxYlic acids. with 1 equiv. c.j rn chlorobenzene lmct hvlamino)naPhthalene].

/ ,F:1 cH3 H c-H. \

r

+

CH,

/

I K. Tamao,T. fatui, M. Akita,T. Iwahara, R. Kanatani, J. Yoshida, andM. Kumada, Tetrahedron,39, 983(1983); Y. Hatanaka andT. Hiyama, J. Org.,54,268(1989). Vitamin B, (Hydroxocobalamin hydrochloride),l. Isomerization of epoxidesto allylic alcohols.t This rearrangementhas been effectedwith strongbasesand variousLewisacids.Enantioselective rearrangement to opticallyactiveallylic alcoholscan be effectedwith catalyticamountsof vitamin B,, at 25o.Thuscyclopentene oxiderearranges to (R)-2-cyclopentene-1-ol in 65% ee. The rearrangementof the crs-2-butene oxide to (R)-3-butene-2-ol in 267oee is more typical.

CH. -

L- \

with Pd[P(C.H,),1, ascatalystandDMF assolvent.TASF canbe replacedby Bu.NF in couplingof the vinylsilaneswith iodoarenes.

cH" ' CH,

OH

O"*ed

h-

I r The reagentsarePrepared I [r;. rrith copperfluoride. are much x:r::rtcdalkenylsilanes with vinyl iodides rp.r:rrreactions It i-lrr--141).Oddly enough,vir\r :hrn I and requirelongerre[c.\ rnactivein this couPling.The particularly | ..! ^rrrhcomponents, i:,r:..

TASF

_* cH,'cH)5'_//'

!

"/^(cHJ5cH!

-!r

cH,cH,),\Jococq

(R, 65%ee)

o

A CH,

CH, (crs)

r H . S u , L . W a l d e rZ , . - d . Z h a n g a, n dR . S c h e f f o l d H.e l v . . 7 l , 1 0 7 3( l 9 S U ) .

Ytterbium(0)' Yb. ketones Reaction of Yb(O) with diaryl Cross'couplingreactionsof ArtOAr' nucleophilic' to group from electrophilic changesthe reactivity oi-'i" tu'Uonyl diaryl ketonescouple with other Thus in the presenceor ;;s tanttranoiJmetal' and 1'3-diols' to give pinacols,a-hydroxyketones, ketones,nitriles, und "po*id.. a' respectively,via the intermediate

)v Org',53' Fujiwara'and H Taniguchi'l. ' Z. Hou, K. Takamine,0' Aoki' H' Shiraishi'Y 6077(1988).

Zeolites. These natural I molecularsievesa someorganicPho zeolitesby treatmc These silicates.dr toP deoxybenzotns

o

i l ^

C,HrytT: cF5 I CrHu + Li-X

of 1 in benzenet zeolite Li-X reer selectivecleava5

I D. R. Corbin.D.

Zinc borohydril RCOCI - | catalyzed bl' Tlv aliphaticac;"Iha bond.The b1-P

' H. Kotsuki.\'. I ( le88).

Zinc-CopPer co of a mixture of , black heavvsuq 1,4-Addida of RI to enon€ H,O (65-25:35

366

r,: \ h(()) with diaryl ketones ririlrophilic to nucleophilic. rl rilir)o€s couple with other d r , , \ \ k e t o n e s ,a n d 1 , 3 - d i o l s ,

Zeolites. These natural mineralsare alkali aluminum silicatesand have been used as molecularsievesand cation exchangers.Recentlythey have beenused to control someorganicphotochemicalreactions.du pont chemistsrhave prepared lithiated zeolitesby treatmentof sodiumaluminumsilicatessuchaszeolite 13x with LiNo.. These silicates,designatedLi-X and Li-y, can effect rearrangement of e-arkyldeoxybenzoins top-alkylbenzophenones in nearryquantitativeyield.Thusphotolysis

o il C.H

/P'g

t

CoH, t l T a n i g u c hJi ,. O r 9 . , 5 3 ,

l CrHo + Li-X

o H c.H.--J-- CH3

L

) CuHi

+ 2:l

2 54Vo

o PrPr c.Hrff c.H, + coH,d-cuHo(cH,),cH,-p HH 3

4

24Vo 4Vo

95Vo

of I in benzeneresultsin 2 and 3 as the major products.photolysis of I in the zeolite Li-x resultsin a trace of 3, with the major product uern! 4, formed by selectivecleavageof the bond betweenC_O and the CHC.H, group. ' D . R . C o r b i nD, . F . E a t o na, n dV . R a m a m u r t h yO , , /r .g . , 5 3 , 5 3 g( l49 S g ) . Zinc borohydride. Rcocl'--> RCHzoH.' This reductioncan be effectedby zinc borohydride catalyzedby TMEDA in ether at 0-40' in g0-95% yield. Both aromatic and aliphaticacyl halidesare reducedreadily without effect on a conjugated double bond.The by-productis TMEDA . (BH,),. ' H. Kotsuki,Y. Ushio, yoshimura, N. and M. Ochi.Bult. Chem.Soc.Japan,61, 2684 ( I e88). Zinc-copper couple.A highly activeZn-Cu couplecan be prepared by sonication of a mixtureof zn andcul (3:1 ratio) in an alcohol-water mixture(-65:3-5).A blackheavysuspension is formedwhichshouldbe usedat once.r r '4-Addition of RI to a.,p-enones.2This coupreand sonication effectaddition of RI to enones.Highestyieldsare obtainedwith r-proH/H,o (4:1) or proH/ H,O (65-25:35-75)as solventfor primaryiodides.C,H,OHiH,O (65;35)is the

36E

Zinc chloride

o

A (/

o

rrb'tr-A

f"'

+ (cH')'cHI :"o

cH'\/ycH,

\^cs(cH,b

* cHl

I CI

solventof choice for tert- or sec-iodides.Yields are decreasedin reactionsof oby a B-methylsubstituent. methylsubstitutedenonesand areparticularlydepressed for this addition. is suggested A radicalreactionoccurringon the metal surface I J. L. LucheandC. Allavena, (1988). Leuers,29,5369 Tetrahedron I J. L. Luche,C. Allavena, (1988). andC. Dupuy,ibid'29,5373 C. Petrier, Zinc bromide. (E)-a,p-IJnsaturatedacids,t Zinc bromide is the most effectiveLewis acid promoting a reactionof C,O,O-tris(trimethylsilyl)ketene acetal (1) with alfor acids.The ketene acetalcan (but not ketones)to form ct,B-unsaturated dehydes (I). in equation be preparedas shown 1) LDA

(D (CH3)3SiCH,COOSi(CH3L #*-

-

(CH,),SiCH:CtOSi(CE)3], I

o Example:

,tol *

Cyclization of giw substitutedat the 2- and G1 and NMR, and can be cenc Ag,O (10 equiv.) in CH.C quinonemethides can undc tors that can survivethe rnr the latter case,the initial p

C.HTCH:CHCOOH (E) CH'

CH,

t M. Bellassoued (1988). Leuers,29,4551 Tetrahedron andM. Gaudemar, Zinc chloride. Cyclopentadienes.tAllyl chloridesthat are monosubstitutedat the central allylic position, such as I, react with 1,3-dicarbonylcompoundssuch as acetyl(3) via an allylateddicarbonylinteracetone(2) to form acetylcyclopentadienes of l with 2 at -78". reactions mediate(a), which can be isolatedfrom

AGo. cltct + lmt H2

(

-s i(c Hr),

369

Zinc chloride

o

"",4.", * L.;-.,&.":l .."Y.", o

9"'

:'

cg(cnr),

in reactionsof orrc .lecreased re--cdbv a B-methylsubstituent. r\ .uggestedfor this addition.

o

;H.L1tn't-'{'tt'

I

I

u*.1-ro'



|

-l'

o2N-cH. C]15 THF 1) LDA 2)Ztf\

%)Io 8O9o

(CH3)TNCHTCOOCTH,rj (cxi sic=ccs:t'ts(ctl')'' cJr' ,

= 47:53 cisltrans = 70:30 (CH,),N

.c=csi(cH3)3

*-r,1a",y, = >99:G t--Glu Gluco Glyca Glyci< Glycc Glycd c-Gly sec4c Glyca C-Gly 9-Gly Glyco o-Glyr Glyco Glyor Glyor Grand Grigl Guan

Hafno (t*Hr a-Hal B.Hd Halo6 Halot Hantz Heck Henci Henrl 3-Hcp It 1,5-H N-Hd Hexa Hexa Hexar Hexar Herar Hexar Herar l( L-Her L-Her Hofm Horm

SubjectIndex D-Glucitol,291 D-Gluconicacid, 139 138 o-Glucono-1,4-lactone, 248 o-Glucosamine, a-o-Glucose.23 200 r--Glucose, Glucosidation,305 Glycals,11l, 200 Glycidicesters,132 162 Glycoaldehyde, Glycol cleavage,294 c-Glycol monoethers,237 sec+ert-|,z-Glycols,92 Glycosidation,119,121,210 312 C-Glycosides, p-Glycosides, 330 Glycosylation,357 o-Glycosyl esterc,2l-22 Glycosylfluorides,l19. 121 Glyoxal,371 Glyoxylate ene reactions,27, 142 Grandisol,28 Grignardreagents,358 Guanine,267 Hafnocene,32 (o-Haloalkenyl)lithiums, 23'l-232 c-Halo carbanions,355 163 B-Halodiisopinocampheylboranes, 218 Halogenation, Halohydrins,163 Hantzschdihydropyridinesynthesis,11 Heck cyclization,248 163 Heneicosadiene, Henry reaction,335 acid, 1633-Heptadecylmonoperphthalic 164 65 1,5-Heptadiene-4-ol, 129 N-Heterocycles, chloride,13 Hexadecyltrimethylammonium triamide,341 Hexaethylphosphoric 164 Hexamethyldisilane, 165 Hexamethyldisilathiane, 269 Hexamethyldisiloxane, Hexamethylditin,42 triamide, 16, 165Hexamethylphosphoric 166 l-Hexenulose,200 l-Hexoses. 200 257 Hofmannrearrangement, 39 Homoallvlbenzenes.

405

Homoallylic alcohols, 83, 209-210, 309 Homoallylicamines,56,247,297 reaction,318 Hosomi-Sakurai Hydration, 197,200 Hydrationof cyanohydrins,295 Hydrazoic acid, 126, 343 Hydridotris(triphenylphosphine)copper hexamer,166 Hydriodic acid, 166 Hydroalumination,137-138 280 Hydroazulenones, Hydroboration,43, 91 Hydrocyanation,103, 130 Hydroformylation,69-70 Hydrogenationcatalysts,250, 265 64 Hydrogenolysis, Hydrogenperoxide,166-167 acid, Hydrogenperoxide-Benzeneseleninic 167 carbonate, Hydrogenperoxide-Potassium 167 fluoride, Hydrogenperoxide-Potassium 167-168 acid, Hydrogenperoxide-Trichloroacetic 168 reagent,13 Hydrogen-transfer 312 cls-Hydroindenes, c-Hydroperoxycarbonylcompounds,243244 Hydrosilanes-Tetrabutylammonlum fluoride, 168-169 Hydrosilylation,33, 135 of 1-alkynes,69 Hydrostannation Hydroxamicacid chlorides,86 hydrochloride,365 Hydroxocobalamin 3-Hydroxycarboxylicacids,364 45 (Z)-4-Hydroxy-l-alkenylcarbamates, 21 2-(c-Hydroxyalkyl)benzothiazoles, p-Hydroxyalkylphenylsulfides,263-264 (Hydroxyalkyl)butenolides, 314 c-Hydroxy acids,149-150 c-Hydroxy carbonylcompounds,21 o-Hydroxycarboxylicacids,41 c-Hydroxy esters,27, 252 o-Hydroxy ketones,92, 366 acids,24 B-Hydroxy-c-amino threo-p-Hydroxy-c-aminoacids,24 B-Hydroxy carbonyl,235 p-Hydroxyesters,294 p-Hydroxyketones,127, 135,148,323 3-Hydroxybutanoic acid, 171

406

SubjectIndex

(R)-3-Hydroxybutyricacid, 171 7 -Hydroxy-2,4-dienoicacids,296 bromide, p-Hydroxyethyltriphenylarsonium r69 Hydroxyisoxazolidines,285 Hydroxy ketones,32 52 Hydroxylactones, Hydroxylaminehydrochloride,170 acid, 170-171 Hydroxylamine-O-sulfonic Hydroxylation, 41, 42, 183-184 Hydroxymercuration,198-199 242 2-Hydroxymethylenecyclohexanone, 241 (S)-2-Hydroxymethylindoline, 139 4-Hydroxy-3-methyl-6-lactones, esters,274 2-Hydroxy-3-oxocarboxylic 2-Hydroxypyridine,152 157 2-Hydroxypyrrolidines, 145 8-Hydroxyquinoline, 55 c-Hydroxysilanes, p-Hydroxysilanes, 223 Hydroxysulphenylation,196-197 vic-Hydroxysulfides,196 1-Hydroxy-1-vinylacetals,312 Hypoioditereaction,151,174 154 Imidazolidinones, Imines, 175-176,273, 317 20'7-208 2-Iminooxetanes, (-)-FK-506,85 Immunosuppressant Indane,57 Indanone,57 Indenols,234-235 Indole alkaloids,254 329 Indolizidinones, Indolizines,219 308 1,2-cyclothiophosphate, rnyo-InositolIodination,70,172 lodine, 172-1'73 Iodine/Alumina, 173 Iodine-Copper(II)acetate,173 Iodine-Hydrogenperoxide,1'13-l'l4 Iodine-Mercury(II) oxide, 174 178 Iodoacetalization, 173 1-Iodo-1-alkynes, IodobenzenedichlorideIPhenyliodine(III) dichloridel,174-175 Iodocyclization,30 39 Iodocyclohexenes, 258 Iododecarboxylation, Iodofluorination,287 o-Iodo ketones,70

30 2-(1-Iodomethyl)oxetanes, 30 2-(1-Iodomethyl)oxiranes, Iodoniumperchlorate,51 175 tetrafluoroborate, Iodosobenzene 178 N-Iodosuccinimide, 175-178 Iodosylbenzene, resins,178 Ion-exchange B-Ionone,163 Iron3* -Montmorillonite, 178-179 Isatoicanhydride,11 Isobutane,198 Isobutene,159 144 Isocyanates, Isoeucommiol,198 Isomerization,365 Isomerizationof alkYnes,135 Isopropenylesters,124 2,3-Isopropylidene-2,3-dihydroxy-l'4(DIOP)' bis(diphenylphosphine)butane 179-180 1,2-O-Isopyrrolidine-o73 glyceroylmethYlPhosPhonate, Isothiazoles,170 87 Isoxazoles, 78 2-Isoxazolines, 148 Isoxazolines,86, Itaconicacids,179 (+)-Ivalin,182 Jonesreagent,92 Julia synthesis,45 hormone,26 (-)-C-16-Juvenile Ketals,222 317 Ketenealkyl silYlacetals, Ketenesilyl acetals,155 a-Keto acids,149-150 B-Keto acids,196 p-Keto amides,196 Keto aldehydes,316 255 1,4-KetoaldehYdes, o-Keto esters,252 B-Ketoesters,206 Ketones,1'76,292 251 meso-Ketones, 53 Ketopantolactone, Ketoximes,157 cyclizations,128 Kharasch-type 99-100' 159 Knoevenagelcondensation, Lactams.176,199

B-Lactam (S)-Laax (S)-Lacr Lactim et Lactone r Lactones b-Lactorx 1-Lacton Lactoniz Lanthan Lasubirr Lawesso Lead(ll ) Leucine L-t-L€uc Lineatoo 2-Lithior N-Lithro l8lLithium. Lithium Lithium Lithium pen Lithium l&r Lithium Lithium 86 Lithium Lithium atE,

Lithium chlc Lithium Lithium Lithium Lithium Lithium Lithium Lithium Lithium Lithium Lithium lm Lithium Lithium Lithium Lithium Tct Lithium

SubjectIndex

r ) ' .: rnf [)loP).

lc

-:

) - . , i 1 .1 5 9

Nl

Lithium tri-sec-butylborohydride'192-193 B-Lactams,82, 150, 181,207, 216' 279' 370 193 Lithium triethYlborohYdride, (S)-Lacticacid, 181 193,222 Lithium trisiamylborohydride, (S)-Lacticaldehyde,181-182 54 2,6-Lutidine, Lactim ethers.337 263 Lactonering exPansion, McMurry coupling, 316-317 Lactones,306 95 Macrocyclization, b-Lactones,306 131 Macrolactonization, 1-Lactones,306 Magnesiumanthracene,194 Lactonization, 105, 245-246 Magnesiumbromide, 194-196 208 LanthanidecatalYsts, Magnesiumchloride-Sodiumiodide, 196 LasubineII, 222 231 Magnesium2-ethoxYethoxide, Lawesson'sreagent,37, 329 194 Magnesium-Methanol, Lead(II) bromide/Aluminum,182 Malonyl radicals,73 Leucine.149 Mandelicesters,125 L-r-Leucine,r-butylester, 182-183 Manganese(III)acetate,71 Lineaton.28 Manganese(III)acetate-Diphenyldisulfide, 228 2-Lithiothiophene, t96-197 N-Lithio-N,N'N'-trimethylethylenediamine, Manganese(II)bromide,234 183-184 dioxide, 197-198 Manganese Lithium, 184 Mannichcyclization,161 Lithium acetylides,173 o-Mannitol. 139.291 148 Lithium alkoxydimethylzincate, reductions,32 Meerwein-Ponndorf-Verley Lithium aluminumhydride-Bis(cyclolMenthol,83 184-185 pentadienyl)nickel, 3 Menthyl (S)-3-(2-pyridylsulfinyl)acrylate, Lithium aluminumhydride-Lithiumiodide' 305 2-Mercaptoalkanols, 185 Mercury,198 27 Lithium/ammonia. Mercury(Il)acetate,198-199 amide' 185Lithium N-benzyltrimethylsilyl Mercury(Il) chloride,200 86 Mercury(Il) sulfate,200 226 Lithium bis(trimethylsilyl)cuprates, 288 O-(Mesitylsulfonyl)hydroxylamine' Lithium borohydride-Chlorotrimethylsilortho -Metallatio n, 23| ane,186 141 Methacrolein, Lithium borohydride-Europium(III) anhYdride,201 Methanesulfonic chloride,186-87 chloride,252 Methanesulfonyl 271 Lithium t-butoxide, 201 a-Methoxyallene, 187 Lithium t-butylhydroperoxide, anhydride,20 p-Methoxybenzenetellurinic 187 Lithium cyclohexylisopropylamide' 85 B-MethoxyboranePane, 188 Lithiumdiethylanlide. 356 (E)-l-Methoxy-1,3-butadiene, Lithium diisopropylamide,188-189 24'7-248 Methoxycarbonylation, 226 Lithium dimethylcuprate, 58 2-Methoxycarbonyl-2-cyclohexenone' 190 Lithiumdiselenide, 74 2-Methoxycarbonylcyclohexenone, 207 Lithium hexamethyldisilazane, 201B-Methoxydiisopinocampheylborane' 3 Lithium hexamethyldisilazide, 202 Lithium N-lithiomethyldithiocarbamates, alcohols'201-202 syzr-B-Methoxyhomoallyl 190 201 (Methoxymethyl)allene, Lithium naphthalenide,61, 99, 190,222 amides,144 N-Methoxy-N-methYl Lithium nitrate. 367 (E,Z)-1-Methoxy-2-methYl-3191-192 Lithium tetraalkylcerates, ene' 202 (trimethylsilyloxy)1,3-pentadi Lithium tetramethylpiPerideisocyanate,259 2-Methoxy-l-naphthyl 192 TetramethylthYlenediamine, acid, 308 (R)-( - )-o-Methoxyphenylacetic 239 Lithium trialkylzincates,

40E

SubjectIndex

203 Methyl (Z)-3-phenylsulfonyl-2-propenoate, B-Methoxy-1-phenylthioketones, Methoxy(phenylthio)methane,202-203 210 Methoxyselenenylation, 29-30 Methyl phenylthioacetate, 113 4-Methoxy-2,2,6,6-tetramethyl(S)-1-Methyl-2-[(piperidinyl)methyl]1oxopiperidiniumchloride,204 pyrrolidine,314 B-Methoxy-2-trimethylsilylborolane, (1S,2S)-( 8 + )-N-Methylpseudoephedrine, 8 Methylaluminum bis(4-bromo-2,6-di4N-Methylpyrrolidin-2-one, 90 butylphenoxide,205 N-Methyl-2-pyrrolidone, 153 Methylaluminumbis(2,6-di+-butyl-4Methylsilyltrifluoromethanesulfonate, 177 methylphenoxide), 141,204-205 Methylsulfenyltrifluoromethanesulfonate, Methylaluminumbis(2,6-diphenylphen210-211, oxide) 205 Methylthioacetonitrile, 102 tert-N-Methylamines, 56 Methylthiomethylethers,146 Methylarenes,126 Methyl p-tolyl sulfoxide,211 N-Methylation,280 Methyl ( - )-triacetoxyshikimate, 3 Methyl bromoacetate,325 Methyl(trifluoromethyl)dioxir ane,212 3-Methyl-2-butenylzinc bromide,239 Mevinic acids.263.272 Methyl cyanoformate,206 Michaeladditions,15, 157, 213-214,313l-Methylcyclohexanol, 99 314 N-Methyl-2-dimethylaminoacetohydroxamicMitsunobuinversion,96, 200 acid.206 Mitsunobureagent,352 Methyl c:dimorphecolate,29 Molybdenumcarbonyl,212-213 (ct-Methyldiphenylsilyl)alkyl ketones,1 Monensin.194 (E)-c-Methyl-o,B-enals, 338 Monoacetalization, 371 6-Methylenebicyclo[3. 3.0]octane-2-ones, 32 Monoperphthalicacid, 163 Methylene-2-cyclohexenes, 91 Montmorillonite,213-214 Methylenecyclopentenones, 54 MontmorilloniteKSF,214 Methylenecyclopropanes, 32, 184 Mukaiyamaaldol condensation, 319 Methylene-1,3-dicarboxylic acid, 184 Mukaiyama'sreagent,85 o-Methylene-B-hydroxy-1-alkoxyketones, 109 1-( 1-Naphthyl)ethylamine, 215-216 (R)-(- )-(l-Naphthyl)ethyl o-Methylene-B-lactones, 243 isocyanate. Methylglucopyranoside, 349 256 Methyl glyoxalate,27 Nazarovreagents,58, 74 alcohols,75 Nef reaction,320 B-Methylhomoallyl Methyl hydrogenmalonate,207 Nickelboride.216 Methyl (R)-3-hydroxybutyrate, Nickel carbonyl, 216-217 207 MethylketeneN-benzylimine,208 Nickel(II)chloride/ZinclPyridine, 217 Methylketeneimines, 207-208 Nickel(Il) cyanide,72-73 Methyl ketones,339 Nileprost,245 Methyllithium,208 N-Nitration, 141 Methyl maleate,59 Nitration, 101 Methyl (E)-4-methoxy-2-oxo-3-butenoate, Nitriles, 130, 176,253,292, 300 208-209 B-Nitro alcohols.335 N-MethylmorpholineN-oxide, 241 Nitro aldol reaction,335 Methyloxidocopperlithium, 226 Nitroalkenes,339 Methyl 2,4-pentadienoates, 207 Nitroarenes,278,295 endo -6-Methyl-5-phenylbicyclo[2.2.2]oct-2- 2-Nitrobenzenesulfenyl chloride,217-218 ene, 300 2-Nitrobenzenesulfinyl chloride,218 Methylphenylsilane, 32-33 2-Nitrobenzenesulfonyl chloride,275 p-Methylphenylsulfonyldiazomethane, p-Nitrobenzenesulfonyl 209 peroxide,218

N-(P-! :l"[

2-Nitr( Nitrog Nitroo l-Nitn N-Nitr Nitroe Nitros Nitrox NMP. Norca (ls.2R Norp.v Nozah Nuckr

2,GOc Octah Octocl Orellil Organ Organ Organ Organ Orgarr Orgar Orgarr Orgarr Organ Organ Orgarr Orgarr Orgarr Osmiu Osmiu pi Oxaza Oxazq Oxazd cis-Or 2-Oxu Oxetal Oxidat Oxidat Oxidat Oxidat Oxidat Oxime Oxirao 4-Oxo

SubjeclIndex

rd O:-

!li:

lf

I

i t:

I !

N-( p-Nitrobenzylidene)benzenesulfonamide,218-219 2-Nitrocycloalkanones, I 67 Nitrogendioxide,219 Nitrones.273. 295 1-Nitro-2-(phenylthio)ethylene, 219 N-Nitrosation,219 Nitrosoarenes, 144 Nitrosolactams. 219 Nitroxides.144 NMP, seeN-Methylpyrrolidin-2-one Norcarboxylicacids,40 ( I S,2R-)Norephedrine, 219-220 Norpyrenophorin,188 Nozaki reaction.95 Nucleopeptides, 218 2,6-Octadienoic esters,185 Octahydronaphthalene, 2i2 Octosylacid, 116 Orellin, 344 Organoaluminumreagents,221 Organoboranes, 221 Organoceriumcompounds,221 Organocopperreagents,Z2l-229 Organocopper/Zincreagents,229-230 Organolithiumreagents,230-231 Organomagnesium/zinc reagents,232-233 Organomanganese(II) halides,234 Organoosmiumcompounds,236 Organosilanes,236-237 Organotinreagents,237-238 Organotitaniumreagents,238 Organozincreagents,lC/l, 238-240 Osmiumtetroxide,240-241 Osmiumtetroxide-Dihydroxyphenylborane,241 Oxazaborolidines, 241 Oxazepines,105 Oxazolidines,chiral, 242 cr's-Oxazolidin-2-ones, 259, 265 2-Oxazolines, 286 Oxetanes,289, 306 Oxidationof phenols,18 Oxidativecontractionof glycals,g6 Oxidativedealkylation,56 Oxidativedecarboxylation, 176, 293 Oxidativedemethylation,71 Oximes,292,317 Oxiranes,98, 306 4-Oxo aldehvde.71

409

2-Oxo-3-alkenoic acids,133 2-(Oxoalkyl)triphenylarsonium bromides, 242 2-Oxoglutaricacid, 153 O x o n e .1 4 4 . 2 1 8 a-Oxo triflates,177 cls-Oxyamination, 265 Oxychlorination,102 Oxygen,singlet,243 Oxytellurinylation,19-20 a-Oxy-o-xylylene, 59 Ozone,243-244 Palladium.245 Pafladium(Il)acetate,t13, 245-247 Palladium(II)acetate-1,3-Bis(diphenylphosphino)propane,247-248 Palladium(II)acerate-Triphenylphosphine, 248 Palladium/Charcoal. 13 Palladium(II)chloride,248-249 Palladium(II)chloride-Benzoquinone. 249 Palladium( tI) chloride-Coppei1ll.1 chloride. 249-250 Palladium(II)chloride-Salicylidenethvlenediamine(salen),250 Palytoxin,186 R-( - )-Pantolactone, 53 PCC, seePyridiniumchlorochromate Pellitorine,35l Penicillanicacids,39 Pentacarbonyl(trimethylsilyl)manganese, 235 2,4-Pentadienoates, 156 Pentaff uorobenzenesulfenyt isocyanate,15 Pentalenene, 89-90, 114 (R,R)-2,4-Pentanediol, 251, 287 4-Pentenyloxymethyl chloride,251-252 Peptidesynthesis,145-146,149 Peracids,274 Periodinaneof Dess-Martin, 52,252 Petersonreaction, 102, 202 Phase-transfercatalysts,252-253 Phenacyldibutyltelluronium bromide,29g Phenanthrenequinone, 254-Z5S Phenanthrenes, 47 Phenanthridines, 189 9-Phenanthrols. 188 Phenethylamines, 253-254 Phenolannelation,66 Phenols, 98,167,173

410

SubjectIndex

Phosphonylation, 36 Phosphoricacid, 266-267 Phosphorusoxychloride (Phosphoryl chloride),267 Phosphoruspentoxide,267 Phosphorylation, 112 Photochemical [2+2]cycloaddition,7 Photo-Claisen rearrangement, 107 [2 + 2]Photocyclization,346 Photocyclization of arylimines,47 Photo-Friesrearrangement, 107 dehydrogenation, Photosensitized 353 Physostigmine alkaloids,127 Picrates,268 Picricacid,268 Pinacol,269 Pinacolcondensation, 282 Pinacolone.269 Pinacols,317, 366 Pinene,221 258 157 2-Piperidines, Phenyliodine(III)diacetate,258 Phenyliodoniumbis(phenylsulfonyl)methyl- Piperidines,20, 44, 1,61 268 1-Piperidino-3,3-dimethyl-2-butanol, ide,259 2-Piperidones, 262 Phenylisocyanate,259, 303 Pivaldehyde,181 Phenyl isocyanidedichloride, 259-260 Pivalonitrile,79 8-Phenylmenthol, 125, 260-261 esters,39 Pivaloyloxymethyl 8-Phenylmenthylphosphonoacetate,Zffi Platinum(IV) oxide, 268-269 chloride,246 5-Phenyl-2,4-pentadienyl Polyethyleneglycol, 274 2-Phenylpropanal, 309 acid, 51 Poly3-hydroxybutyric Phenylselenol esters,329 Polyketides,46 Phenylselenophosphonic dichloride,261 dichloride,93 Polyoxochromium Phenylselenoquinones, 18 Polyphosphoric acid trimethylsilylester, 4-(Phenylsulfonyl)butanoic acid,262 269 nes,264 3-(Phenylsulfonyl)-ALisoxazoli Polypropionate1,3-diols,224 284 Phenylsulfonyl methyl selenoketone, 4-Polystyryltritylamino acids,359-360 1-Phenylsulfonylpropanol-2, 262-263 POM ethers,21 c-Phenylthiocycloalkanones, 265 Potassium,269 o-(Phenylthio)ethers,6l 270 Potassium3-aminopropylamide, syn-o-Phenylthio-B-methoxy alcohols,192Potassiumt-butoxide,271-272 193 Phenylthiomethylenetriphenylphosphorane,Potassium-l8-Crown-6,270 Potassiumflioride,272 263 Potassiumfluoride-l8-Crown-6.272-2'/3 Phenylthiomethyl(trimethyl)sil ane,263-264 Potassiumfluoride-Hydrobromicacid, 273 Phenylthionitrileoxide, 264 Potassiumhexamethyldisilazide,286 (Phenylthio)nitromethane, 264-265 Potassiumoxomonosulfate, 212 carbonyl,203 1-Phenylthio-p,'y-unsaturated 273-274 Potassiumpermanganate, Phenylvinyl sulfoxide,115 Potassiumperoxymonosulfate,278 Phosgene,265 Potassiumpersulfate,274-275 Phosphines,chiral, 265-266 Potassiumsuperoxide,275 256 Phospholipids, 195 Potassiumtri-sec-butylborohydride, 348 Phosphoniosilylation,

m-Phenoxybenzyl alcohol,145 Phenylarenedithiocarboxylates, 150 N-Phenylation,352 Phenylboric acid, 254-255 S-Phenylcarbonochloridothioate, 255 1-Phenylcyclohexene, 241 (N-Phenyl)dialkynylimines, 259 Phenyldichlorophosphate*Sodium iodideDimethylformamide,255 Phenyldichlorophosphite, 256 enol ethers,127 1-(Phenyldichlorosilyl)silyl Phenylethylisocyanate,256 N-Phenylfluorenyl-l-alaninal, 49, 50 group, 49 Phenylfluorenyl (25,3S)-3-Phenylglycidol, 341 Phenylglycine, 153 o-2-Phenylglycinol, 256-257 Phenylhydroxamic acid, 285 Phenyfiodine(III) bis(trifluoroacerate), 257-

Pro Pro 1.1 Pro Pro B.P Pro Pro Pro Pro Pro Pro Pro Psc Psc Psc Psc Psc Pun

S'r $r $n $n $n $n $n $n $n $n 2-h Sn $n Pln

Qui

Qul Qur Qur p-Q Qul Qul Quir o-Q

Ran Ran Red Red Red Red Red

SubjecrIndex

D

7

Prolines,24 Propane-1,3-dithiol, 114 1,3-Propanedith iol, 242 Propargylicalcohols,316 Propenylcuprate, 224 es,224,270 B-Propiofacton Propyne, 124 Propynylethers,270 Prostaglandins, 45, 199 Protection, 251-252 Protectionof amino grotps, 21,7-2lg Protodesilylation, 7 Proton Sponge,364 Pseudo-o-o-glycopyranose, 23-24 Pseudoguaianolides, 1l7 Pseudopterosin A, 66 Pseudo-B-r--pyranose, 24 Pseudosugars,23 Pummererrearrangement, 2,11,269 Pyranosides,24S-49 Pyraziniumchlorochromate,2il5-276 Pyrazole,344 Pyridinecarboxylic acids,160 Pyridinesynthesis,170 Pyridiniumbromideperbromide,276 Pyridiniumchlorochromate , 5j, 66,276 Pyridiniumfluorochromate,57 Pyridiniumpoly-(hydrogenfluoride), 121 Pyridiniump-toluenesulfon ate, 7g_79, 276 2-Pyridones,160 Pyridoxal,153 P y r r o l e s , 8 11,4 7 Pyrrolidines,44, 132 Quina alkaloids.277 Quinazolines,87 Quinidine.277 Quinine,277 p-Quinones,257 Quinonemethides,369 Quinonemonoacetals, 205 Quinones,173.294 a-Quinones, 18,361 Ramburg-Backlundreaction,271 Raneynickel, 184,278, 329 Reductionof o,B-acetylenic esters,194 Reductionof an enone. 137 Reductionof carbonylcompounds,333 Reductionof ozonides.44 Reductiveacylation,206

4Il

Reductive alkylation, 27-28 Reformatsky-type reaction,323 Reimer-Tiemannformylation,84 Remotechlorination,174 Resolution,67, 135,256 Resorcinols,60 Retro-Diels-Alderreactions,100 Rhodium(Il) benzoate.279 Rhodium(II) carboxylares, 278 -280 Ring expansion ,82, 174,292 Ritter reaction,197.339 Ruthenium(III)chloride-Tributylphosphite, 280-281 Rutheniumtetroxide,281 SADB see(S)-(- )-Amino-2-(l-methoxy-lmethylethyl)pyrrolidine (SADp) Salicyclaldoxime, 86 Samarium(Il)iodide,282-284 Samarium(II)iodide-TetrahydrofuranHexamethylphosphoric triamide,2g4 Samarium(III)chloride.282 S a r c o p h y tB o l, 3 1 7 schwartzreagent,80 Secogalioside, 88 Secoiridoids. 88 Secologanin,88 Selenabicyclics, 42 Selenaldehydes, 42 Selenium.165 Selenium(IV) oxychloride, 89 Selenoacetals, 101 Selenocarbonyl compounds,261 Selenocyanogen, 284 Selenoimidates, 330 Selenoketones. 284 Seleno-Pummerer rearrangement, 336 SEM ethers,298-299.344-345 Semicarbazide, 284-285 Sensitizers, 37 (S)-Serine.24 Sharpless epoxidation,322 Shikimicacid.3 Shodomycin,855 Silica,285 Silicon(IV)fluoride. 286 Siloxyalkynes, 60 Siloxymethylation, I l8 Silverfluoride/Calciumfluoride.2g7 Silveroxide, 369 Silverperchlorate,127

4t2

SubjectIndex

316 Silvertrifluoroacetate. Silylation,107 p-Silylaldehydes,69 Silylcobaltcarbonyl,118 Silylcyclopropanes,344 178 N-Silyldihydropyridines, 334 B-Silyl-c,B-enals, Silylenolethers,51 Silylformylationof alkynes,334 Silyl keteneacetals,19, 178 o-(Silyloxy)allylethers,61 Simmons-Smithreagent,287,324 Singlet oxygen, 294 356-357 Smilesrearrangement, Sodium aluminum silicates,367 Sodium anthracenide,288-289 150 Sodiumarenedithiocarboxylates, Sodiumazide,106 289 Sodiumazide-Dimethylformamide, ate, 289 Sodium benzeneselenol Sodium benzyloxide,289-290 Sodiumbis(2-methoxyethoxy)aluminum hydride, 290 Sodiumborohydride,290 Sodiumborohydride-Cerium(II)chloride, 291 Sodium borohydrideTrifl uoromethanesulfonicacid, 291 Sodiumborohydride-Zirconium(IV) chloride,292 Sodiumbromite, 292 Sodium dichloroisocyanurate,292-293 SodiumO,O-diethylphosphite,293 SodiumO,O-diethylphosphorotelluroate, 293 Sodium-Ethanol.288 Sodiumhydrogenselenide,293 Sodium hypochlorite, 293 Sodiummolybdate(Vl)-Hydrogen peroxide,294 Sodiumnaphthalenide,165 Sodiumperiodate,294 294 Sodiumphenylseleno(triethoxy)borate, Sodium(potassium)amide, 288 Sodiumtetraborate,295 Sodium tetracarbonylhydridoferrate,295 Sodiumthiosulfate,134 Sodiumtungstate,295 Sorbic acid, 296 73 D-erythro-C8-sphingosine, Sphondin,94

Squaricacid,296 Staudingerreaction, 360 Steglichesterification,131 Stilbenes,47 Streckeramino acid synthesis,103 170 Streptonigrinoids, Styrenes,156-157 C-Sucrose,96-97 o-Sulfenyl aldehydes,202-203 esters,19 o-Sulfenyl-B-hydroxy Sulfides,218 o,B-Sulfinylepoxides,211 2-Sulfinylindole,127 3-Sulfinylindole,126-127 de, 297 N-Sulfinyl-p-toluenesulfonami Sulfonylhypohalites,218 Sulfoxides,71, 218,292 Sulfoximines.135.288 Sulfur,297 329 Swainsonine, TanshindiolB, 363 Tartaricacid, 103 Taxols,152 TDA-I, 356-357 Tebbenitriles,79 Tellurium.293.298 298 Tellurobenzaldehyde, Telluroniumylides,298 308 1,4,5,6-Tetraacetyl-nyo-inositol, 2l 2,3,4,S-Teta-O-benzyl-o-glucopyranose, Tetrabis(triphenylphosphine)palladium, 1,27 Tetrabutylammoniumfluoride, 27, 75, 304 fluoride-HexaTetrabutylammonium methylphosphorictriamide, 298-299 hydrogensulfate,73 Tetrabutylammonium Tetrabutylammonium (tricarbonylnitrosyl)ferrate,299 118 Tetracarbonylmethylcobalt, Tetrachlorophthalicanhydride, 300 300 2,6,9,l0-Tetracyanoanthracene, Tetracyclization,12 Tetraethylammoniumacetate,240-241 Tetrafluorophthalicanhydride, 300 Tetrahalomethane,182 Tetrahydrobenzopyrans,301 Tetrahydrofurans,60, 227 188 Tetrahydropyranylacetic, 353 Tetrahydropyranylation, Tetrahydropyranylethers, 168

Te

Tet

l.: Tet

2.

Te Te Te

l.l Tc Tc

Tc

Tt Th Th [2 Th Th Th Th Tt TI TI tTt TI TT Tt TI TT TI TT TI TI TI

Th L . ,

Tir Tx Tir Til

Tir

SubjectIndex

F-

il. ln,'.c. ll

h;r. -i. l,q 6 :+r [air

9

I

--i

413

Tetrakis(triphenylphosphine)palladium(0),Tin(II) trifl uoromethanesulfonate300-304 Tributyltin fluoride, 314_315 Tetrakis(rri-p-tolylphosphine)palladium(0),Titanacyclobutanes, 79 l5l Titanium(0),315 2,2,3,3-Tetr amethylbutane, 19g Titanium(III) chloride-potassium / GraphTetramethyldiamides, 46 ite,316-317 2,2,6,6-Tetamerhyl-2,6-disilapiperidine, Titanium(III) chloride-Sodium 304-305 cyanoborohydride, 317 Tetramethylethylenediamine, 16 Titanium(III) chloride-Zinc/coppercouple, Tetramethylorothocarbonate. 305 J t I Tetramethylsuccinamide, 46 Titanium(IV) butoxide/Copper(I)chloride, l, 1,3,3-Tetramethylurea, 305 316 Tetraphenylantimony iodide, 306 Titanium(IV) chloride,317-320 Tetraphenylantimony trifluoromethanesul_ Titanium(IV) chloride-Lithiumaluminum fonate,306 hydride,320-321 Tetraphenylporphyrine, 243 Titanium(IV) chloride-Magnesium, 321 -B-o-galactopyranosyl_ Titanium(IV) 2,3,4,6-Tetrapivaloyl chloride-Titanium(IV) amine,103,307 rsopropoxide,321-322 Thallium(I) carbonate,47 Titanium(IV) isopropoxide,322 Thallium(III) nitrare,86 TMEDA, seeTetramerhylethylenediamine Thienamycin,207 p-Toluenesulfonyl azide, 323 [2-Thienyl(cyano)copper]lithium, 228 (N)-Tofuenesulfonyl)phenylgly cinol, 242 Thiiranes,305 o,p-Tolyl sulfoxide,2l 1 Thioacetals, l0l.2l4 N-Tosylimines, 297 Thioacylsilanes, 97 Transacylation, 206 Thioaldehydes, 97 Transamination,l3 Thioamides,275 Transesterification. 84 Thioesters.121 Transferhydrogenation,13,27g Thioethers,166 Transylidation,35I 1-Thio-B-o-glucopyranoside, 210 3,4,6-Tri-O-acetyl-B-o-glucopyranosyl Thiogfucosides,210-2ll chloride,305 Thioglycolates,113 Trialkylchlorosilanes, 323 Thioimidates,331 Trialkylsiloxyalkynes, 60 Thiolaceticacid, 307-308 o-Trialkylsilylpropionaldehyde, 338 Thiolactones,165 Trialkylstibines,323- 324 Thiols. 37 Trialkyltin hydrides,324 Thionolactones, 332 Tribenzyl-o-glucal, ti6 Thiophosphorylchloride,30g Tributylarsine,325 Thiosalicylamides, 187 Tri butylphosphine-Zinc, 325 Thiourea.243 2-(Tributylstannyl-4,4-dimerhyl-2-oxazoline, Thiourea-Titanium(IV)isopropoxide, 124 309 (Tributylstannyl)methyl ethers,60 Thioxanthen-9-ones, 187 Tributylstibine,325 I--Threonine.3 Tributyltin hydride, 69, 325-333 Tin(II) chloride, 182,309-310 Tributyltin hydride-Tributylphosphine Tin(IV) chloride, 142.3tt-313 oxide, 333 Tin-Aluminum. 309 Tributyltin hydride-Triethylborane, 333 Tin(II) chloride-Chlorotrimethvlsilane. 1,4,7-Tricarbonyl compounds,203 3 l 0 - 3 1I Tricarbonyl(5,8-dimethoxynaphTin(II) trifluoromethanesulfonate, thalene)chromium. l6 31 3 - 3 1 4 Tri-r,r-carbonylhexacarbonyldiiron, 334

414

SubjectIndex

Tricarbonyl(naphthalene)chromium, l6 Tri-to-carbonylnonacarbonyltetrarhodium 334 [tetrarhodiumdodecacarbonyl], Tricarbonyl(triphenylphosphine)nickel,

334-33s vic-Tricarbonylcompounds,253-254 Trichforoethylene, 270 Trichloroisopropoxytitanium, 335-336 Trichloromethyltitanium, 238 3-(2,4,6-Trichlorophenoxyacetamido)pyridine, 356 1,1,1-Trichloro-3,3,3-trifluoroacetone, 336 Tricyclicergolines,35 Tricyclohexylphosphine, 31 Tridachione,102 Trienals,133 1,3,5-Trienes,246 N-1-Triethylallylimines, 75 Triethylamine,336 Triethylammoniumbis(catecholato)alkenylsiliconates,336-337 Triethylborane , 32, 337 Triethyloxoniumtetrafluoroborate,337-338 Triethylsilane,15 Triethylsilane-Titanium(IV) chloride,338 Trifluoroaceticacid. 338-339 vic-Trifluoroacetoxysulfides, 196 'frifl uoromethanesulfonic acid, 339 Trifluoromethanesulfonic anhydride,339340 Triffuoromethylation, 340,341 N-p-Trifluoromethylbenzylcinchoninum bromide,340 Trifluoromethylbromide,340 Trifluoromethyltrimethylsilane, 341 1,1,1-Trifluoro-2-propanone, 212 5-Trifluorouracil, 340 Trifluorperacetic acid, 148 Tri(2-furyl)phosphine, 33 1,2,3-Trimethoxybenzene, 269 Trimethoxymethylsilane, 7- 8 Trimethoxysilane-Dilithium 2,3-butanediolate,341 Trimethylaluminum,140,238. 341-342 5-Trimethylcyclohexenone, 89 Trimethylgermanium halides,342 Trimethyl orthoformate, 342 2-Trimethylsiloxy azides,16- 17 1-Trimethylsiloxy-1-phenylethylene,129 2-Trimethylsilyl-3-alkylindenols, 235 Trimethylsilyl azide, 342- 343

343 1-Trimethylsilylbutadienes, 344 Trimethylsilyldiazomethane, 247 1-Trimethylsilyll-3-dienes, Trimethylsilylenol ethers,177 chloride, B-(Trimethylsilyl)ethoxymethyl 344-345 (Trimethylsilyl)ethoxymethyl ethers,298 (2-Trimethylsilylethylidene)tris(2-methylphenyl)phosphorane, 345-346 2-Trimethylsilylethylidinetriphenylphosphorane,345 346 Trimethylsilylisoselenocyanate, Trimethylsilylketeneacetal,129 chloride, Trimethylsilylmethylmagnesium J45

83 Trimethylsilylmethylpotassium, O-Trimethylsilylcyanohydrins,346 I -(Trimethylsilyloxy)-2-alkoxycarbonylcyclopropanes,272 346 2-Trimethylsilyloxy-1,3-butadiene, Trimethylsilyltriflate,66, 102, 108 Trimethylsilyltrifluoromethanesulfonate, 346-350 I -alkenes,350 2-Trimethylstannyl(E)-3-Trimethylstannyl-2-alkenoates, 350 (Trimethylstannyl)copper(I)-Dimethyl sulfide,350 (Trimethylstannyl)copper reagents,350 Trimethylstannyllithium, 347-348 ethylide,351 Triphenylarsonium ylides,350-351 Triphenylarsonium Triphenylbismuthdiacetate,352 37 Triphenylmethanol, Triphenylmethylchloride,359-360 halideTriphenylmethylphosphonium Potassiumt-butoxide,352 tetrabromide, Triphenylphosphine-Carbon 352 Triphenylphosphine-Diisopropyl azodicarboxylate,352-353 hydrobromide,353 Triphenylphosphine 2,4,6-Triphenylpyrylium tetrafluoroborate, 353 l'-binaphthol, 136 3,3'-Triphenylsilyl-1, Triplex catalysis,129 Trisaccharides, 5I Tris(dibenzylideneacetone)dipalladium (chloroform),353-354 Tris(diethylamino)sulfonium 169 difluorotrimethylsilicate,

Tris

Tris

Tris Tnl

Tris

c.o

Trisl Tng l.l-

Trit( N.T Tnn Trin Tnn Tntr Tntr

Trr

Tuh Tvlo

Ug Ulln Ulln Ultr Ultr o.p

9.r

6.e o.p o.$ Urr Urc

Van

Ven Veti

(-) Vin

SubjectIndex Tris(diethylamino)sulfonium difluorotrimethylsiliconate, 355 Tris(6,7,7,8,8,8-heptafl uoro-2,2-dimethyl3,5-octanedionato)europeum orpraseodymium, 355 Tris(6,6,7,7,8,8,8-heptafl uoro-2,2-dimethyl3,5-octanedionatoytterbium, 356 Tris[2-(2-methoxyethoxy)ethyl]amine, 356358 Tris(2-methylphenyt)phosphine, 345 C,O,O-Tris(trimethylsilyl) keteneacetal, 368 Tris(trimethylsilyt)silane, 358-359 Tris(triphenylphosphine)nickel(0), 359 1,1,2-Trisubstituted dihydronaphthalenes, 230-231 Triton B, 144 N-Tritylaminoacids,359-360 Trityl chloride,359-360 Trityl chloride-'iin(Il) chloride,360 Trityl ethers,168 Trityl hexachloroantimonate, 15, 360-361 Trityl perchlorate,361-362 Tryptamine,254 Tubercidin.357 Tylophorine,260 Ugi condensation, 307 Ullman ether synthesis,145 Ullmann reactions,99 Ultrasound.363 Ultrasoundactivation,197 0,8-Unsaturatedacids,368 amides.247 B,1-Unsaturated 6,e-Unsaturated epoxides,8l o,B-Unsaturated esters.325 c,B-Unsaturatednitriles,325 Uracils,22 Urea, 154 Vanadyltrichloride(Vanadium oxytrichloride),364 Verrucarol,9 Veticadinol,160 (-)-Vetivone,89 Vinvl acetate.7l

41S

Vinylallenes,57 Vinyl bromide,225 Vinyl(chloro)silanes, 364 Yinylcuprate, 224 Vinylcyclobutanols, 346 Vinyl cyclobutylamines, 130 Vinylcyclopropylsilyl ethers,l0g 2-Vinyl-1,3-dioxolan-4-ones, 31_32 Vinyl ethers,347-48 Vinyl(fluorodimethyl)silanes, 364-365 Vinyl Grignardreagents,133 Vinyl halides,118 Vinyliodonium salts, 176-77 Vinyliodoniumtetrafluoroborates, 6, 176_ 177 Vinylketenes,60 Vinyllithiums,4l,225 Vinylsilanes,202 Vinyl sulfones,210 Yinyltin,225 Vitamin B,, (Hydroxocobalamin hydrochloride),365 Vitamin E, 54 Wilkinson'scatalyst,91 Williamsonsynthesis,77, l16 [1,2]Wittigrearrangement, 134 [2,3]Wittigrearrangement, 61, 165,210 Wittig-Horner reactions,73-74, 260_ 261 Wittig reactions,157,298, 325,3Sj Wittig-Smilesreaction,352 Xanthen-9-selonones, 187 Ytterbium(0),366 Zeolites,367 Zinc chloride,368-371 Zinc(II) chloride,103, 139, 152-153 Zinc borohydride,36T Zinc bromide,368 Zinc-Coppercouple,367-368 Zinc powder,325 Zirconiumsulfate,371 Zirconocene,32