( ,..,,,
Fieserst
Reagentsfor OrganicSynthesis VOLUME EIGHTEEN
Tse-Lok Ho National Chiao Tung University Republicof C...
23 downloads
1359 Views
23MB Size
Report
This content was uploaded by our users and we assume good faith they have the permission to share this book. If you own the copyright to this book and it is wrongfully on our website, we offer a simple DMCA procedure to remove your content from our site. Start by pressing the button below!
Report copyright / DMCA form
( ,..,,,
Fieserst
Reagentsfor OrganicSynthesis VOLUME EIGHTEEN
Tse-Lok Ho National Chiao Tung University Republicof China
A WILEY-INTERSCIENCE PUBLICATION JOHN WILEY & SONS,INC. NEW YORK/ CHICHESTER / WEINHEIM / BRISBANE/ SINGAPORE / TORONTO
f h i s b o o k i s p r i n t e d o n a c i d - f r e ep a p e r . @ C o p y r i g h t O 1 9 9 9b y J o h n W i l e y & S o n s ,I n c . A l l r i g h t s r e s e r v e d .P u b l i s h e ds i m u l t a n e o u s l yi n C a n a d a . N o p a r t o f t h i s p u b l i c a t i o nm a y b e r e p r o d u c e d ,s t o r e d i n a r e t r i e v a l s y s t e mo r t r a n s m i t t e d i n a n y f o r m o r b y a n y m e a n s ,e l e c t r o n i c ,m e c h a n i c a l ,p h o t o c o p y i n g ,r e c o r d i n g ,s c a n n l n g o r o t h e r w i s e ,e x c e p ta s p e r m i t t e d u n d e r S e c t i o n s 1 0 7 o r 1 0 8 o f t h e 1 9 7 6 U n i t e d S t a t e s C o p y r i g h t A c t , w i t h o u t e i t h e r t h e p r i o r w r i t t e n p e r m i s s i o no f t h e P u b l i s h e r ,o r a u t h o r i z a i i o n t h r o u g h p a y m e n t o f t h e a p p r o p r i a t ep e r - c o p y f e e t o t h e C o p y r i g h t C l e a r a n c eC e n t e r , 2 2 2 R o s e w o o dD r i v e , D a n v e r s ,M A 0 1 9 2 3 ,( 9 7 8 ) 7 5 0 - 8 4 0 0 ,f a x ( 9 7 8 ) 7 5 0 - 4 ' / 4 4 .R e q u e s t s t o t h e P u b l i s h e rf o r p e r m i s s i o ns h o u l d b e a d d r e s s e dt o t h e P e r m i s s i o n sD e p a r t m e n t , J o h n W i l e y & S o n s ,I n c . , 6 0 5 T h i r d A v e n u e ,N e w Y o r k , N Y 1 0 1 5 8 - 0 0 1 2 ( 2, 1 2 )8 5 0 - 6 0 1 1 . f a x ( 2 1 2 ) 8 5 0 - 6 0 0 8 ,E - M a i | : P E R M R E Q @W I L E Y . C O M . Library of Congress Cataloging in Publication Data: ISBN 0-471-24477-s
r s s N0 2 7 1 - 6 1 6 x Printedin the UnitedStatesof America. 1 0 9 8 7 6 5 4 3 2 1
PREFACE My first contact with organic chemistry was through the textbooks and experimental manual written by ProfessorL. F. Fieser and Mrs. M. Fieser.These works rmpressedme not only with their organizationand lucidity, but the appearanceof a compilation of reagentsas an appendix really arousedmy curiosity about research tools. This feature was not found in any other textbook, and was a harbingerof the tamous and successfulseries,Reagentsfor Organic Synthesis. T h e F i e s e r sw i l l l o n g b e r e m e m b e r e df o r t h e i r o u t s t a n d i n gc o n t r i b u t i o n s t o chemicaleducation.Their dedicationto providing a quality serviceduring the latter part oftheir lives playedan important role in the rapid advancesoforganic synthesis during the past thirty years. The quick retrieval of essentialinformation through consultationofthe seriesmust havesaveduncountableman-hoursin research.and in the courseof such readingsthere must also have been occasionsthat a chemist became inspiredto developimproved or new syntheticmethods. The "ROS" referenceseriesis an establishedinstitution. That is the main reason wiley & Sons decidedto continue its publication.In acceptingan invitation to authorship with great trepidation,I can only hope that my feebleefforts will prove to
"usinga dog'stail to substitute bemorethanmerely for a mink,s.',ffilfu/ffiE{)
The previousformat is essentiallymaintained,exceptthat more conventionalreferenceabbreviationsare used. Due to space limitations and my attempt to cover many more papers,unnecessaryexplanationsare omitted. with the same considerations, a generaltransformationthat can be describedin a short sentencewithout ambiguity is deemedsufficient, and the correspondinggraphicsare dispensedwith.
Tse-LoxHo
CONTENTS
ReferenceAbbreviations x l Reagents I Author Index
419
Subjectlndex 480
REFERENCE ABBREVIATIONS ACR ACS .{CIEE .{JC .{OMC BBB BCSJ BSCB BSCF
Acc. Chem. Res. Acta Chem. Scand. Angew. Chem. Int. Ed. Engl. A u s t .J . C h e m . Appl. Organomet.Chem. Biosc. Biotech. Biochem. B u l l . C h e m . S o c .J p n . B u l l . S o c .C h i m . B e l g . B u l l . R u s s .C h i m . F r .
BRAS
B u l l . R u s s .A c a d . S c i . Chem. Ber. C h e m .C o m m u n . Collect. Czech. Chem. Commun. Can.J. Chem. Chem. Lett. C h e m .P h a r m .B u l l . Carbohydr. Res. Dokl. Chem. (Engl. Trans.)
CB CC CCCC CJC CL CPB CR DC G H HC HCA HX IrC(B) IJS(B) J\CS JCC rcCS(T) iC R(S) JCS(Pl) JFC JHC JUC l\P JOC .'O\lC
G a z z .C h i m . I t a l . Heterocycles Heteroatom Chem. Helv. Chim. Acta Huaxue Xuebao I n d i a n J . C b e m . ,S e c t .B I n t . J . S u l f u r C h e m . ,P a r t B J. Am. Chem.Soc. J. Carbohydr.Chem. J. Chin. Chem. Soc. (Taipei) J. Chem. Res. (Synopsis) J. Chem. Soc. Perkin Trans. l J. Fluorine Chem. J. Heterocycl.Chem. J. Med. Chem. J. Nat.Prod. J. Org. Chem. J. Organomet. Chem.
xii
ReferenceAbbreviations
JOCU LA MC NJC NKK OM PAC PSS RJOC *tC S SC SL SOC T TA TL YH
(Engl' Trans') J. Org' Chem' USSR Liebigs Ann' Chem' MendeleevCommun' . New Journalof ChemtstrY NiPPon Kagaku Kaishi Organometallics Pure APPI' Chem' PhosPhorusSulfur Silicon RussianJ' Org' Chem' Recl' Trav' Chim' PaYs-Bas Synthesis S Y n t h 'C o m m u n ' SYnlett (JPn') SYnth.Org' Chem' Tetrahedron Tetrahedron:AsYmmetrY Tetrahedron Lett' Youji Huaxue
l-Acetamido-2,2,6,6-tetramethylpiperidin-1-oxyl (1). Glycoloxidation.t The tosicacidsaltof 4-acetamido-TEMPO is a mild oxidizIng agentthat convertsglycolsto a-dicarbonyl compounds. NHAc
OH Br
\
-.'\.,..OH l ) < -\? l | /
w'
TSOH . HzO
+
\ l
Br
l /
\ . {
cH2cl2
/ - N - \ I
Br
00,1h-> 180,24 h
89%
(1) '\Nalter, \f . G. Banwell,V. S. Bridges,J. R. Dupuche, S.L. Richards, andJ. M. JOC 59, 6338 t 1994).
Acetic anhydride. Acetylation,' In the presenceof freshly prepared MgI2 (from Mg and 12in dry r'ther),Ac20 acetylatesprimary, secondary,and tertiary alcoholsas well as phenols. Cyclization,2 Acetic anhydride provides a diketene unit on reaction with ureas rn the presenceof DMAP.
o Me.rA*-err t
l
H
H
O"rO ,
o Me.rA*.en
DMAP, Py rt,2h
o24u" 59"/"
Rearrangement-cyclization t 6-Oximino nitriles form 2-acetamidopyridines ,,n treatmentwith Ac2O-AcCl under reflux. The reactionproceedsfrom rearrangernent of N-acetoxyenaminesto C-acetoxy imines, which undergoelimination and ;rclization.
.,G-
Ac2O,AcCl a,4h
NHAc 69%
Pummerer rearrangement.a 7-sulfinyl acids give y-thio-y-butyrolactones. In a .clenium version,sthe rearrangementproduct (with a a,a-difluorinated selenoxide) rrn reactwith cyclic ethers.
ll" tr
2
AcetYlene
llli"illl11!!J.T:3,;i1:,1*lWglli.l]3i,lls1':i*:r""^:: "strirai' r Kumamoto' DLr and i.nffi:f
:f;jV:**;,il.;;: 'll:';l*"t"'
;;.";;' K
o r
34' l3ll (lee3)' andK' Maeda'rL Y' rokunaga'
-.''' ^"fiilj:ilH,HlAs *l'i","'1":[1iT:Til:il',:l]Jl,: "" acvanide the permits ,, J;il;;ni
it or atrvrhalides'
Wlostowski'SC rp. Dowd,B. K. Wilk' and M'
t! I't
!!!
23'2323(1993)'
Eri r-l rrtatt
tu-
I to amides in acetonitrile Acetonitrile' 15.' , alcohols are converted Benzyl Ritter rcaction" ' OEtz' presenceol BFr SC24' 601(1994)' andH' Badparva' A' R' Sardarian' rH. Firouzabadi'
in the
thus chloride' 3' i . ^-., -.lcoholsare convertedto chloridesl a c-Acetoxyisobutyryl Primary chlorination'' Regioselective selectively' alditols react ""o,"tl"itu Acq
t*5
u
t
lbll
aF :r rl
-t3..v
J-coct I
"o^l&o" HO
' M. Benazza, M'
dioxana;
,TT
Cl OAc
Ac2o,py 527"
( 1994) y' JCC 13'96? andG' Demaill Uzan' R' Massoui'
t#: n"'?;;:,t#t f,I",to"oo; Primarv:'".".Y: : :'Jl'".;11 l'X"f;I :H'ffi:' ip.,ioin. rf, "".i;;;;";l'rt.:',"1',),i;:."-'Jl"::::1fi < diisoProPYlethYlamine' (1993)' oto'IOC58'3791 andH' Yamam 'K. Ishihara' H' Kurihara'
in KoH-DMSO' acetylene Acetylene. N-vinylationwith .oleundergoes PYrt VinYlafion't
D5 i rJ It
ti N-Acvlaziridines
a\
, .q9l).
I
\./
N
?*J v
H KOH,OMSO
6 1603
1200,2 h
A,. G . M a l ' k i n a A , . l . M i k h a l e v aL, . B r a n d s m aa,n dB . A . T r o f i m o vS, C 2 4 , O.A. Tarasova 203s( 1994).
n r tr i l e s
Acetyl hypobromite. N-Bromination.t
Amides are brominated with AcOBr in CCl,r at room
lemperature. L. Duhamel,G. Ple,andP. Angibaud,SC 23,2423(1993).
k :n the
2- (4- Acetyl -2- n itrophenyl)etha nol. Carboxyl group protection.t The crr-estersof aspartic and glutamic acids are tbrmed readily using the DCC method, after the geminal functionalities are sequestered (by reaction with EtrB). The acid can be regeneratedunder conditions r0.l M Bu+NF) that do not affect an N-Boc group.
dc.. thus
o
AOS".*o2
U**
o {@---t--,A^ I Y H2N-- - -BEt2
^f-f"o' \Z
\-,'\
"Ht
H2N- - - -BEt2
DCC, CH2Ct2
J . R o b l e s ,E . P e d r o s o ,a n d A . G r a n d a s ,S l 2 6 l ( 1 9 9 3 ) .
\'-Acylaziridines. Polyketides.t Preparedin a one-potreactionfrom RCOOH,(COCI)r,EtrN, and are suitableacyl donorsfor thesereagents rn aziridine(e.g.,2-methylaziridine), with theirpolyanions. via reaction compounds of poly-1,3-dicarbonyl --hain extension I ih. Pres;,'llrdine,
NaH.THF: BuLi:
Ph^\/ 00,
B Lygo.IL 35. 5073(1994)
O
*A-I-""oot''
.A,.cooBuf
-D\tso.
O
't h
; ao.nct
\
96v"
tn
4
AcYltelluranes
Acylmethylenetriphenylphosphoranes' pyrolysis of these stabilized Wittig Acetylene precursors'Flash vacuum reagentsremovestriphenylphosphineoxidetofurnishacetylenes.Bothterminal'and by this method' are accessible intJrnal acetylenes2'r
PhsPrl H
,P
LfI
-n
R 59-82'/"
Ph3Pr1 ,P
X
looo
RO \:\
!o
Po
cl
ctco
R = Me
'L.
72/o
, n d M . P r e t o r , S 1 0 7 9( 1 9 9 3 r . F. Tietze,C. Schneidera
c.ulting rh H:oz d e f in e d rR;NH, ( ) n e sb y
A l k y l a l u m i n u mc h l o r i d e s1. 3 ,5 - 8 ; 1 4 ,4 - 5 : 1 5 , 2 - 5 ; 1 6 , l - 3 ; 1 7 :4 - 7 reactionof a dioxalenium Mukaiyamaaldolization.t The intramolecular with a silyl enolethersidechaingivesdioxabicyclicproducts. OMe
qlP orr.
.fl.-\
Et2AtCt/ CH2Ct2
o--\-\
Lo -7"
Fo
-200,2h 65o/o
\ b()faneS ' reactlon
Ene reactions. The intramolecular version is suitable for the construction of Excellentl . 3 - c h i r a l i t yt r a n s f e ri n t h i s p r o 12-, 14-,and l6-memberedring systems.2 cessis evident.r
l1s.pond-
OH EtAtCt2/ CH2C|2
. / - \ / / \ / 1
-780
Pr3SiO 667.
t: \r lth an ln moder-
2-(Alkenylmethyl) cyclic ethers are formed by the reaction of lactols and alkenes." Diels-Alder reactions. Diethylaluminum chloride depositedon silica seemsto be a superiorcatalyst.5Methylaluminum dichloride alone is effective in promoting Intramolecularcycloadditionsinvolving a furan ring as the diene.' Reaction of the 1,3-dipolar species derived from methyl [3+2]Cycloaddition. ketone with silyl vinyl ethers furnishes functionalized cy1-phenylthiocyclopropyl clopentanes.TA related reaction is the trapping of a fragmented cyclobutane.E
o z\
_
+
SPtr
TBDPSO
\/-
M€2A|Cl/ CH2C|2
)""3sen TBDPSO4-
1l chloride 76%
fir
t
Alkylalumlnumchlorides
reactwith
carbonv.t" i on of eno.tizabte Atkytat : !! !i,!o]r:..fr"r:J;J!es to gtv
stereoselectively orgunoiu.inum chlorides
CONMe2
'
'l 'I
Faner!|tltJa:ri '1 l. Tr.bI L:lrar L lrrd l, \.-lraar
MeAlC12
oHc.:r,coNMez
CHzGlz oo -> 250
THldroxy
66% (97:3)
ester enolates is epoxide opening by esters'to The catalyzed
toN-crotonvr,,",Jo'"iiJ".i*,,';:li,:::'TilTil,.}i:{iliilil,',,"", ch,oride reacThe corresponding showsl'5-asymmetricinduction' 4-benzyloxazolidin-2-one photoactivation' ,t* *nn MezAlClrequires
W*Yo O O
PhMs-hexans - 780, 0.8 h
, . . O O
Thus S k c l e t a t r e a r r a n g e m e n t . | z T h e f u s e d r i n gring - s y sskeleton t e m ( 1 )(2)' con t a i nthe i n glatter acyclobutene to a:itYo its straino,;;"t";"tent Ticlq-mediated unit releases initial the availablein two steps,inuoruin'g classof compoundsare enones' cvclic to of the properalkvnes il;;;;Jdition
I
TBS
/l
at
:l\ ( -1/
rtfrihtf |'ll.frtia
i Zn9l2lCH2CI2 CAN, CO, MeOH
Noz
'rc
-780
Noz 71"/"
t
rt
"T:Ytn pTd
O
12h
u"/"
34
Benzotriazol-l-ylory trlr(al-
Benzotriazol-l-ylmethylimino(triphenyl)phosphorane
rA. R. rA. R. rA. R. 1A. R. 5A. R. oA.R. 7A.R.
K a t r i t z k y , S . R a c h w a l ,a n d G . J . H i t c h i n g s , T 4 7 ' 2 6 8 3 \ 1 9 9 1 ) . K a t r i t z k y , K . Y a n n a k o p o u l o u ,a n d H ' L a n g , J C S ( P I ) 1 8 6 7( 1 9 9 4 ) ' Katritzky, w.-Q. Fan, and Q.-H' Long, S 229 (1993). Katritzky, H.-X. Chang, and J. Wu, S 907 (1994). Katritzky and M. F. Cordeev, JOC 58' 4049 (1993). K a t r i t z k y , Z . Y a n g , a n d J . N . L a m , J o C 5 8 ' 1 9 7 0( 1 9 9 3 ) . K a t r i t z k y , R . A . B a r o c k , Q . - H . L o n g , M . B a l a s u b r a m a n i a nN, ' M a l h o t r a , a n d J ' V '
G r e e n h i l l .S 2 3 3 ( 1 9 9 3 ) .
(Ero)2PoH BuLi,20e _
2",-N. ''N I ll \,./-tl \-N'
2\-N. ''N I ll \.^-r.t'
Benzotriazol- 1-ylmethanol. N-Alkylation of amiiles.t Benzotriazol-1-ylmethylation on the nitrogen atom of an amide is accomplishedin refluxing aceticacid. Benzotriazolecan then be displacedby reactionwith an organometallicreagent(RzZn, etc.). On LiAlHq reduction N- methylaminesare obtained.
GI
.pphe
NaH
.pphl
THF,a
//
-|
)-N'
A . R . K a t r i t z k y , J . J i a n g ,a n d J . V . G r e c n h r l t -- A . R. Katritzky, R. Mazurkiewicz,C.V. Src
'A. R. Katritzky,G. Yao,X. Lan, andX. Zhao,JOC 5E'2086(1993)'
N- (Benzotriazol- l-ylmethyl)carbamates. 1,1-Bis(heteroaryl)alkanes.r The benzotriazole unit has a lower leaving tendency than the carbamoyl group in the presenceof a Lewis acid. Accordingly' Friedel-Crafts alkylation of very reactive arenes(heteroarenes)is feasible.However' the benzotriazole can be replaced in the second step.
riY\'\Z\r.r' ,)--
**"o.*'
ZnCl2
cHs
cHzcr2 n
Benzotriazol-1-yl methyl methyt etbcr. Dimethyl acetals.t Deprotonarion ol alkylation serveto elongatethe sidechtra acetalson heatingwith TsOH-MeOH.Th
A . R . K a t r i r z k y , Z . Y a n ga,n dD . J .C u n d 1S.
Benzotriazol-l -ylmethyl phenyl sulttdc 2,2 - Diarylc yclopropyl phe nyl sa[ila rhe reagentis deprotonatedwith LDA io r zole acts as a leaving group in the ring-c trvesalso undergothe same reaction.
A. R. Katritzkyand M. F. Gordeev, SL 2lJ | | ' A. R. Katritzky,L. Xie, andW.-Q.Fan,JoC 58' 4376(1993).
Benzotriazol- l-ylmethytimino(triphenyl)phosphorane. reactions.t Phosphonomethyliminophosphoranesare readily wittig-Horner prepared. These novel compounds form unsaturated heterocycles on reaction with dialdehydes. Homologous phosphine imines undergo elimination of benzotriazole to give (Nwhich are useful for the synthesisof pyridines.2 vinylimino)phosphoranes,
Benzotriazol-1 -yloxy tris(d imethyhrit hexafluorophosphate (1). Dipeptide synthesis. Among varb least problems due to racemization arr ob
are the 6-trifluoromethylbenzotriazolc: r Hydroxy-7-azabenzotriazoleitself is an cft edditional advantageof being a visual id endpoint.l
Benzotriazol-l-yloxy tris(-N. ''N I ll \-/-r.r'
!
\-N'
BuLi,20o
*|]'(-o,,n.
rYcHo \r^cgo
.pph.
3S
a'il-\ \r-\.7N
l r - - : - ' i r r a n . N . M a l h o t r a .a n d J . V .
"""-
fY\* \-/'\N'
fi< -
i:l(rn on the nitrogen atom ir: 5:r./(rtriazolecan then be disr:. r.On LiAlH4 reduction IR
,.pph3
THF, ^
,,'"n,
PhcH=cHcoph
Ph
/-*
rN 59%
R. Karritzky,J. Jiang,andJ.V. .- A. A'R'Katritzky,R . M a z u r k i e wGreenhill, i c z , c . V .JOC s , " " rSE,l987 * , * a M .(t993). F.Gordeev, JOC59,2140(lgg4\. ..
v._)lr
Benzotriazol-l-ylmethyl
- . r h a s a l o w e r l e a v i n gt e n , [,c*rs acid. Accordingly, I l r ' : ' i :.ne\ ) is feasible.However. lr:
rt
c F. I
methyl ether. Dimethyl acetars.t Deprotonation of the methyr ether with BuLi and subsequent afkylation serve to erongatethe side chain. The a-benzotriazoryr ethersgive dimethyl acerarson heatingwith TsoH-MeoH. Thus thereagentis a methyrar anion equivarent. A. R. Katrirzky,Z. yang,and D. J. Cundy,SC23, 3061 0993).
Benzotriazol-l-ylmethyl
phenyl sulfide. 2,2-Diarylcyclopropylphenyl sulfides.t
Th, r.hereage ntr, o.proton ut"owitrrLDain,r,"pr";fn"#:tti:T;ill
;.;.::ffi J[: zoleactsas a reavinggroupin the ring-crosure step.simprerbenzotriazoryr rivesalsoundergothe same deriva_ reaction. A. R. Katritzky andM. F.Gordeev, Sa213(1993).
t ' - '
Fra ne. rl -' -.'phosphoranesare readily tc; :ererocvcleson reaction with Irr. : ,'t benzotriazoleto give (Ni\ :: ie\ri of pyridines.2
8enzotriazol-l -yloxy tris(dimethylam ino)phosphoniu m bexafluorophosphate (l). Dipeptide synthesis' variouscouplingreagentsthe besryierdsand the 1-o:t hast problemsdue to racemization are obr"ru"d *irt, ,t i, satt (l)r. St;;;;; reagenrs
""i t-",uu"" zotriazote3 anarogs. [Note:til'r:::r:r::Tffi:T,:t'"nzotriazote2 an.efficient
peptidecouplingaoaitru"e.i dditionat advantage It hasthe ", o:Iltttll's etnga vlsualindicator(yellow to colorless) of the reaction endpoint.l
36
N-Benzoyl'(4S)-t-butyl-2'oxazolidinone
Benzylamine. Fluoroalkyl- and fluoroarylash form resin as catalyst) with fluoro carb treatment with EtrN. Hydrolysis of tb
N )u N
PFo'
O-P(NMe2)g
amines.
(1)
r J . D u d a s h ,J r . , J . J i a n g , S ' C ' M a y e r ' a n d M ' M ' J o u l l i e ' S C 2 3 ' 3 4 9 ( 1 9 9 3 ) ' Boom' and W' tJ.C.H.M. Wijkmans, J.A.W. Kruijtzer, G'A' van der Marel' J'H' van
''>N.,\Ph R
Btoemhoff, RTC ll3, 394 (1994)' L ' A ' C a r p i n o 'a n d M ' B i e n e r t ' T L 3 4 ' t A . E h r l i c h ,S . R o t h e m u n dM , ' B r u d e l 'M ' B e y e r m a n n ' 4 7 8 1( 1 9 9 3 ) . rL. (1993). A. Carpino, JACS l15, 439'7 '
3-(Benzotriazolyl)ProPYne' -'-i-irytpyuoin.t at the sp terminusof the proR"u"tionwith N-tosylimines p a r g y l b e n z o t r i a z o l e f o | l o w e d b y i n t r a m o l e c u l a r S u b s t i t u t i o n ( a n d aavailromatization_ are also a new syntheticprotocol'2-Hetarylpyrroles detosylation)represents ableby this method. I A. R. Katritzky,J. Li, andM' F' Gordeev's 93 (1993)'
r B . S . J u r s i cS, C2 3 ,3 6 1( 1 9 9 3 ) '
o
J't
Ph.
Mee r wein - Pon n dorf-Ve rlc y rtJt tor asymmetric reduction(36-96% 1r r-PrOH.
D. A. Evans,S.G. Nelson,M. R. Gagrr. e
N- Benzoyl-(4S) -t-butyl-2'oxazolidinone' Benzoylation.ln-Alkylcarbinolsshowkineticselectivitiesintherangeof2030: I for reactionof the (R)-enantiomers'
| I -Ph Ho-
(R,R)-3-Benzyl-1,5-diphenyl-3-ezrp
o-
N-BenzoYltetrazole. and amines with the N-acyl-5-phenylteAcylation.t Derivatization of alcohols applicable'The mixture in THF is uniformly is trazole in the presenceof pyridine to complete the reaction' kept at -10'C and then at room temperature
P1 ( -N-az ' Y
v . A . S o l o s h o n o k ,A . G . K i r i l e n k o , V . P X
'
MoMsBr Et2HH2cl2 oo'2h
Bzo Ph (95o/. ee)
' D. A. Euans,J.C. Anderson, andM K' Taylor'TL 34' 5563(1993)'
"olrn
.V-Benzylidenebenzenesulfonam ilc. Knoevenagel reoction.t As surn *ith active methylenecompounds.thc :nce of EtrN in chloroform the reruol :r-sulfonylketones,a-nitro esters.and
't\'.W.Zajac,T. R. Walters,J. Buzby,J. G1
Benzyloxyketene. Iterative chain extension.' 12+21 Jerivatives,which can be openedand p
Benzyloxyketene37 Benzylamine. Fluoroalkyl- and fruoroarrramines.t Imines formed (with Dowex-s' H*form resin as cataryst) with fruoro carbonyl compounds undergo prototropic shift on treatment with Et:N. Hydrolysis of the benzylideneisomers gives the fluorinated amrnes. k , _ : ' ( . 2 J . _ r 4 9( 1 9 9 3 ) . . . j - i.: \tarel. J.H. van Boom, and W ni - - .
{ C a r p i n o .a n d M . B i e n e r t ,7 L 3 4 ,
fr
lF,^,n
R-C-N=C-ph
rl, 4h
79-980/"
l r : - - r . . r t t h e s p t e r m i n u so f t h e p r o cu :' .:h.trlution (and aromatization)-Hetar.v"lpyrroles are also availt.\
HCt, Et2o
fr
R_C-NH. HCI H 87-991"
V . A . S o l o s h o n o kA, . G . K i r i l e n k o , V . p . K u k h a r , a n d G . R e s n a t i ,T L 3 5 , 3 l l g (lgg4).
rR'R)'3'Benzyr'1,5'diphenyr'3'azapentane-1,5-dioxysamarium(III) iodide(t).
Bn -ph 'r^T--Y
ph..,
l * - i
o_sm_o I
I ln j .:-' ree. * ith the N-acyl-5-phenylte, : r i r c a b l e .T h e m i x t u r e i n T H F i s r. t , ::llete the reaction.
(1)
Meerwein-ponndorf_Verley reduction,t The samarium iodide is a catalyst tor asymmetric reduction(36_ g6Eo yield, up to 97Voee) of carbonyl compounds by r-PrOH. D. A. Evans,S.G. Nelson,M. R. Gagne, andA. R. Muci,"/ACSf 15,9g00(1993).
\ -:' . .electivitiesin the ranse of 20-
:
+
BzO"'\Ph
xolpr'
.\'-Benzyl idenebenzenesulfonam ide. Knoevenager reaction.t As surrogate for benzardehyde in the condensation *ith active methyrenecompounds, the benzenesulfonimineis superior. In the pres_ ence of EtrN in chroroform the reaction with, inter aria, B-diketones,p-keto esters, a-sulfonyl ketones.a-nitro esters, and malononitrile proceedsat room temperature. w.W. Zajac,T. R. Walters, J. Buzby,J. Gagnon,andM. Labroli , SC 24,427(lgg4).
(95% ee)
Benzyloxyketene. ? _ r { r i 6 - 1( 1 9 9 3 )
Iterative chain eilension.t [2+2]cycroaddition with imines provides B-ractam Jerivatives,which can be opened and processedinto new imines to renew the reaction
2.2' -t 3E
BenzYltrichloroacetimil
or removedas desired'The chain extensequence.The amino group may be retained and 2-amino-l'3-diols' sion method is useful to constructsy'?-poly-l'3-diols OBn OSiRs
"no)
Et3N/ CH2C|2
'D. BharandS. Chandrasekaran, S 785( 19
^^
osiR3
Benzyltriethylam mon ium tetratb ior Sulfur transfer.' The reaction s'il fides. Interestingly,I,l'-binaphthalenc the reactionwith the bis-diazoniumsal
NAr
a\ II NAr
Benzyltrimethylammonium dichlorr Introduction of an Iodination.t enamino ketonesis readilv achievedr'i
5 8 ' 1 6 4 6( 1 9 9 3 ) ' ' C . P a l o m oJ,. M . A i z p u r u aR, ' U r c h e g u ai ' n dJ ' M ' G a r c i a ' J O C
K. Matsuo.S. Ishida.and Y. Takuno.CPI acid' "o-(2-Benzyloxyethyl)benzoic 'acid conventhe esterification of an alcohol with this For irr"u", orot"riion.t by hyis achieved cleavage The suitable' tional methods (e.g., DCC) are usually lactonization' induce to l-BuOK with Jrogenolysis(Hr' Pd/C) followed by treatment which liberatesthe alcohol unit'
.'\yAon i l l \z9osn
o
o
o
AAon
Hz, Pd-C
R
l l l \Z\-^OH
AcOEt rl
2,2' - Bis(d iphenylphosph i no)-l,l'-trir 15, 34; 16, 32-36: 17, 34-38 Palladiumcomplexes. Asymmetric alkenylation and arl
O
H
+
'rYq l l l l \t^"/
QH2Cl2 n
TfO_._r-.r
f-il
(o)
\,
85-96% (overallyield)
(1994)' IY. Watanabe, M. Ishimaru,andS Ozaki'CL2163
Benzyl trichloroacetimidate' 13' 32 Alcoholbenzylation.|ThederivatizationiscatalyzedbyTMSoTf,whichdoes compounds' not causeracemization of sensitive chiral
Chiral morpholines and pipcnzn .ubstitutionsof 1,4-diacetoxy-2-bute promoted by Pd(0) complexes.In thc p grvesoptically activeproducts.
Lactimbenzylethers.2Cyclodipeptidesareconvertedtothebislactimethers, whicharevaluableintermediatesforstereoselectivea-aminoacidsynthesis.
aoH
l \ttHBn
or1* HN--,\o
.
tno;n* cr3c
A'\-*'
+
l
A' ."
BnOa,,^:* MftSiOTl
il
tl
N.-Aoen vn2wt2
ri
61"/"
(1993)' r P . E c k e n b e r g ,U . G r o t h , T ' H u h n ' N ' R i c h t e r ' a n d C ' S c h m e c k ' T 4 9 ' 1 6 1 9 ( 1 9 9 3 ) ' 3 2 1 L A 2U. G r o t h , C . S c h m e c k ' a n d U ' S c h d l l k o p f'
F Ozawa, Y. Kobatake, and T. Hayashr. I F. Ozawa, A. Kubo, Y. Matsumoto. T. Hr oM 12,4t88 (t993). \ ' . U o z u m i , A . T a n a h a s h i ,a n d T . H a y r t r
2,2'.Bts(diphenytphosphino)_1,1,_binaphthyt (BINAp)
r \ r : . : . J e \ i r e d .T h e c h a i n e x t e n ! i . : I - a m i n o -1 . 3 - d i o l s .
oBn oSiR.
/..l r -
39
Benzyltriethylammoniumtetrathiomolybdate. sulfur transfer.t The reactionwith arenediazonium sartsleadsto diaryl disul_ fides'Interestingly, l,r'-binaphthalene-2,2'-dithior is the onryproduct(6lzoyield)in the reactionwith the bis-diazonium sartderivedfrom l,l,-binaphthyl-2,2,-diamine. 'D.
B h a r a n d S . C h a n d r a s e k a r a nS , 7g5 0994).
Benzyltrimethylammoniumdichloroiodate. Iodination.t Introductionof an iodine atom to the centrarcarbon atom of enaminoketonesis readilyachieved with the reagent.
(1993) 5t. t6.16
'K.
M a r s u o ,S . I s h i d a , a n d y . T a k u n o , CpB 42, ll4g (lgg4).
a - . ' - ' h o l u i t h t h i s a c i dc o n v e n -
T . : - .J\aqe is achievedby hyr ' 3-t )K to rnducelactonization.
o L'- -
F
o
H
h.,
-
r-\l
l
l l \v\-,,
2,2'-Bis(diphenytphosphino)-l,1,-binaphthyt (BINAp). f3, 36_37; 14,38_44, 15, 34; 16, 32-36; 17,34_38 Palladiumcomplexes. Asymmetric alkenylation and arylation.t,2
o
a .''or)
85-9606 roverall yield)
(alBtNAPl2Pd
""rT lM".
.Y\
SB/" (A7"/"eel
It:., r.i hr TMSOTf, whichdoes d. r , \ : . r : : . J r o t h e b i s l a c t i me t h e r s , | . , . ' . n ( )a c i d s y n t h e s i s .
chirar morphorinesand piperazines-. The ring formationby tandemartytic substitutions of 1,4-diacetoxy-2-butene with 1,2-amino arcohols and r,2_diamrnes is promotedby Pd(0)complexes. In the presence of a chiral BINAP ligandthis reaction givesopticallyactiveproducts.
aoH l-NHB.
\-,/ :
4-'voAc l
* Aco/
- , _ z _ N
h- ... I
r { 9 . 1 6 1 (91 9 9 3 ) .
rR)€tNAP Et3N,THF
' 5 o et nl 61%
Pd2(dba)3
ro>,""\ t l
'N'
Bn 72o/o (650/o ee)
F. Ozawa,Y. Kobatake,and T.
S"tilli;rt
Hayashi, TL 34, 2505(lgg3).
Y' Matsumoto, r' Havashi, s. Niriioru,K. yanagi, andK. Moriguchi, ,ir!1]'
Y. Uozumi,A. Tanahashi, andT. Hayashi , JOC Sg,6g26(tgg3\.
40
(BINAP) 2,2'-Bis(diphenylphosphino)-1,1'-binaphthyl
Platinum complexes. Baeyer-Villiger oxidation.t In kinetic resolutionsof chiral ketones(as racemic mixtures) up to 587oee has been observed.The configuration of the migrating carbon is retained. ' A . G u s s oC, . B a c c i nF, . P i n n a a, n dC . S t r u k u l O , M 1 3 , 3 4 4 2( 1 9 9 4 ) .
Rhodium(I) complexes. Intramolecular hydrosilylation.t The yields and ee values of this reaction are dependenton substratestructuresand solvents.There are subtle mechanisticvariations that are not clearly understood.
tJ. B . H o k e , L . S . H o t t i s , a n d E . W . S t e r n .. l O "L. S h a o ,H . K a w a n o , M . S a b u r i ,a n d y , L U 'K. M a s h i m a , K . - H . K u s a n o ,N . S a r o . y . I { Y . H o r i , T . I s h i z a k i , S . A k u r a g a w a ,a n d H .
l,l' -Bi-2,2' -naphthol (BINOL) bororr Hetero-Diels-Alder reactions.t n analogs)to chiral imines catalyzedb1.t
able BINOL ligands proceedswith good, induction operatesfor matching pain. rl hand, the reaction of achiral substralesro rise to productsin good ee.2
' X . w a n ga n dB . B o s n i c hO M 1 3 , 4 l 3 l ( 1 9 9 4 ) . ,
Ruthenium(ll) complexes. Aymmetric hydrogenation.t An extension of the general method to varrous aamino a,o-dicarboxylates has been accomplished,furnishing products with 70987o ee. A r u t h e n i u m ( I I )c o m p l e xc o n t a i n i n ga n o c t a h y d r o - B I N A Pl i g a n d :h a sb e e nt e s t e d hydrogenationof conjugatedacids. for its effectivenessin inducing enantioselective
r{
n2
cooH
MeOH 1o-25o
Reduction
of carbonyl groups.
cooH 83% (93%ee)
Aldehydes and ketones are subjected to enan-
tioselective reduction. Hydrogenation of benzaldehyde-a-d,3 a-alkoxyketonesa'5 or Bk e t o e s t e r s 6 T sc a n b e a c c o m p l i s h e d u s i n g e i t h e r t h e R u d i h a l i d e c o m p l e x e s o r s o m e modified forms. a-Ketoestersv are also similarly reduced. 'T. Pham and W. D. Lubell, JOC 59,3676 (1994). tX. Z h a n g , T . U e m u r a , K . M a t s u m u r a , N . S a y o , H . K u m o b a y a s h i ,a n d H . T a k a y a , S L 5 0 1 ( 1994). tT. O h t a , T . T s u t s u m i , a n d H . T a k a y a ,J O M C 4 8 4 , l 9 l ( 1 9 9 4 ) . o E . C e s a r o t t i ,P . A n t o g n a z z a , M . P a l l a v i n c i n i , a n d L . Y i l l a , H C A 7 6 , 2 3 4 4 ( 1 9 9 3 ) . sE. C e s a r o t t i ,P . A n t o g n a z z a , A . M a u r i , M . P a l l a v i n c i n i , a n d L . Y i l l a , H C A 7 5 , 2 5 6 3 ( 1 9 9 2 ) . oJ.P. l, . Mallart, X. Pfister, L. Bischoff, M.C.C. G e n e t ,C . P i n e l , V . R a t o v e l o m a n a n a - V i d a S d e A n d r a d e , S . D a r s e s ,C . G a l o p i n , a n d J . A . L a f f i t t e , T A 5 , 6 6 5 , 6 7 5 ( 1 9 9 4 ) .
OSiMe. I
R
\ ' rlpn
\
\oMe
tprort Brc. crlro,
H
The (RO)aBH species in which rhc -1.3'-bis(o-hydroxyphenyl)-BINOLproyes rhe Diels-Alder cycloaddition.rAlmog e r orable case. B-Amino esters.a By means of doud and a chiral BlNOl-boronate catalysr. rh a simple method for the synthesis of &r Hydroxy-B-aminoestersare similarly ro
yamamoto,SZ 129(l99jr. . K. HatroriandH. 'K. HattoriandH. yamamoto,249, l74g tlg{ K. IshiharaandH. yamamoto,"/z{CS lla. tJ6 'K. Hattori,M. Miyata,and H. yamamoro. .r_ K. Hatrori and H. yamamoto,I50, 27gStlg.l
l,l' -Bi-2,2' -naphthol-lanthanide
coof Nef reaction.t.2 Optically acrive p-b condensationof nitromethane with aldcbg as catalyst.
1 , 1 ' - B i - 2 , 2 ' - n a p h t h o l - l a n t h a n i d e c o m p l e x e4 sl
s
t-
:. rrl ketones(asracemic :r ,rf the migrating car-
a-
rc. of this reactionare .tl!' mechanisticvarta-
J: ,
tJ. B . H o k e , L . S . H o l l i s , a n d E . W . S t e r n ,J O M C 4 5 5 , 1 9 3 ( 1 9 9 3 ) . "L. S h a o ,H . K a w a n o , M . S a b u r i , a n d Y . U c h i d a , 7 4 9 , 1 9 9 " 1( 1 9 9 3 ) . 'K. M a s h i m a , K . - H . K u s a n o , N . S a t o , Y . M a t s u m u r a , K . N o z a k i , H . K u m o b a y a s h i ,N . S a y o , Y . H o r i , T . I s h i z a k i , S . A k u t a g a w a , a n d H . T a k a y a ,J O C 5 9 , 3 0 6 4 ( t 9 9 4 ) .
l,l' -Bi-2,2' - naphthol (BINOL) boronates. Hetero-Diels-Alder reactions.t The cycloaddition of Danishefsky's diene (and analogs)to chiral imines catalyzedby boronatesderived from commercially available BINOL ligands proceedswith good diastereoselecriviry.The double asymmetric induction operatesfor matching pairs, which exhibit fast reaction rates. On the other hand,the reactionofachiral substratesin the presenceofchiral binol-boronatesgives rise to productsin good ee.2
9
OSiMe3
-.,1ntethodto varlous d- : n r p r o d u c t sw i t h 7 0 -
?
t_
i\-* |
"'Dpn H
i ' l r s a n d :h a sb e e nt e s t e d ,n oi conjugatedacids.
't1 l]"-
),,
ll-oMe
o
.\ l
BINOL CHzClz
il r^f '
*
,\ l
r."tf'
",'l-tn n
ll
"'f pr, H
20 - 630/" (99:1-86:14)
83% (93% ee)
The (RO)aBH species in which the four oxygen atoms belong to the chiral -1.3'-bis(o-hydroxyphenyl)-BlNol proves to be an exrremely selecrive catalyst for rhe Diels-Alder cycloaddition.iAlmost exclusivelyone product is obtained in a farorable case. p-Amino esters.4 By means of double stereodifferentiation using chiral imines
:c' are subjected to enan-
and a chiral BlNol--boronate catalyst,the condensationwith ketenesilyl acetalsis r simple method for the synthesisof B-amino esters in optically active forms. aHydroxy-B-aminoestersare similarly accessible.s
a ooH
| .-.
-
(Pho)38
cr-alkoxYketoneso5orBR.- : rrlide comPlexes or some
Ir , r
d-- r -:
K. HattoriandH. Yamamoto, .lt 129(1993). K. HattoriandH. Yamamoro, I49, 1749(1993\. K. Ishiharaand H. Yamamoto, "/ACS1f6, l56l (1994). 'K. H a t t o r iM , . M i y a t a a, n dH . y a m a m o r o , . / A CUSS , l l 5 l ( 1 9 9 3 ) . K. Hattoriand H. Yamamoto, 250, 2785,l994't.
1 1 - . . , . h r . a n d H . T a k a Y a 'S L 5 0 1 F. ll: ::,. { 16. 2344 (1993)' J' , . \ rlla. HCA 75,2563 (1992\ r ' \ P i i s t e r .L . B i s c h o f f ,M ' C C A i - ^ : . 6 7 5( 1 9 9 4 ) .
l,l' -Ri- 2,2' - naphthol - lantha n ide complexes. 17, 28- 30 Nef reaction.t'2 Optically active B-hydroxy nitroalkanes are obtained in the ;ondensationof nitromethanewith aldehydesusing a BlNOl-lanthanum complex .rr catalyst.
42
1,1'-Bi-2,2'-naphthol-tin(IV)chloride
@o. |
eryo
oAcn'o I
(Y\
v
,La oH
o/Y'*o, OH
ni\-*t
I
@
cH3NO2 THF, -500
=-,'=,
'
K . I s h i h a r a , M . K a n e e d a ,a n d H . Y a m a r u
BO"h(92"hee)
prepared from (i-PrO)rLa promotes Michael reactions.2 A BINOL complex Michael reactionswith excellentresults' enantioselective derived from lanthanide chlorides' Alkylation.3 Organolanthanide reagents with good stereoselectivity' alkyllithiums, and BINOL add to aldehydes Diels.Alderreactions.aTheversionwithinverseelectrondemandinvolvingapyronesandvinylethersiSsubjectedtoasymmetricinductionbyaBlNol-ytterbium complex.
I
COOMe
2-vt ( . 6 + r l
r-o"u
Yb(oTD3,iPr2NEt (B){+)-BINOL
o
-.O-\,,COOl,/t"
+A OBu
l,l' -Bi-2,2' -naphthol/titanium con; In addition to the chiral BINOL-h1 usingdiisopropoxytitaniumand oxotitr
ferent degrees. Ene reactions.t The enantiosckt reaction of glyoxylate is effective usio reactionof fluorala also attains a hig Chiral catalyststhat contain substituc
Both allylstannanes' Allylation. bonyl substratesin enantioselectiveand rationi of a very effective catalyst froc the need for stirring, heating or coolil of the methodology. Under such cond rained by substituting the allyl rcageil
82"/" (53"kee)
a I
r H . S a s a i ,T . S u z u k i , N . l t o h , a n d M ' S h i b a s a k i ' T L 3 4 ' 8 5 1 ( 1 9 9 3 ) ' 116' l57l (1994)' rH. S a s a i ,T . A r a i ' a n d M ' S h i b a s a k i ' J A C S Pease' TA 4' 2407 (1993)' E t J and Lyford, L K. Chibale, N. Greeves, 103' 295 ' 1 . 8 . M a r k o , G . R . E v a n s , l - ' e ' O " t t " " q ' J ' F e n e a u - D u p o n t 'a n d B ' T i n a n t ' 8 S C B
\ PhCHO +
CH2=C=CHSnBu3+ ?
\
( r994).
The fornrr Aldol condensation.' iilyl acetalsand aldehydesmay actuall migration. chiralformswhenmeso-cyclicl,2-carboxylicanhydridesanddicarboximidesare Michael reaction.to Using enocr treatedwith the complexat low temperature' rnd a chiral BINOL-TiO catalyst, thc t 42' 9 (1994)' ' K . M a t s u k i , H . I n o u e ' A . I s h i d a , M ' T a k e d a ' M ' N a k a g a w a 'a n d T ' H i n o ' C P B ralues range from moderateto highly-
16' I 33 l,l' -Bi-2,2'-naphthol-lith ium aluminum hydride' are obtainedin hydroxylactams and Enantioselectivereductions't Lactones
l,l' -Bi-2,2"naphthol-tin(IV) chloride' Enantioselectiveprotonati'on.|Cleavageofenolsilylethersandketenebis(triketonesand esters' alkylsilyl) acetalsby the complexleadsto chiral
Y. Motoyama, andK. Milec M. Terada, 'V. Terada, and K. Miler S. Matsukawa,
IL 35. ll K. Mikami andS. Matsukawa, 'K. Mikami, T. Yajima,M. Terada,E. Kr
I,l'-Bi-2,2'-naphthol/titanium complexes 43
osiEt3
r
f
f
i
t
H o cH2cr2
Y\"",. all-f"* .,,.i, (, aY'n a-,b-{""'' \"' " \.\2
, \1^*o,
,,*""
' o H 'K.
I s h i h a r a ,M . K a n e e d a a, n d H . Y a m a m o t o , , / A C S lf6, lll79 (1994).
8c*. 92".ee)
r , P r C ) r , L aP r o m o t e s rn:h:ntde chlorides, a.:l\lt\.
dc:r.rndinvolving ar : ill\OL-Ytterbium
I I
::oMe
-5!
l,l'-Bi-2,2'-naphthol/titanium complexes. 15, 26-27; 16, 24-25; 17, 28-30 In addition to the chiral BINOL-ligated dichlorotitaniumcomplex, the variants usingdiisopropoxytitaniumand oxotitaniumspeciesare shown to be effectiveto different degrees. Ene reactions.t The enantioselectivesynthesis of a-hydroxy esters from ene reactionof glyoxylate is effective using vinyl chalcogenides2 and allylsilanes.iThe reactionof fluorala also attains a high level of enantio- and diastereoselectivities. Chiral catalyststhat contain substituentsin the BINOL moiety havebeen evaluated. Allylation. Both allylstannanes5 and silanes6transfertheir allyl groupsto carbonyl substratesin enantioselectiveand diastereoselectivemanners.The facile preparationTof a very effectivecatalystfrom BINOL and (i-PrO)qTiina2:l ratio without the need for stirring, heatingor cooling is most advantageous in future applications of the methodology. Under such conditions homopropargylic alcohols are also obtained by substitutingthe allyl reagentwith allenyltributylstannane.t
(ot)"'
-
phcHo+ cH2=c=cHSnBu3+ 9?o" T : , r r . B S C B1 0 3 '2 9 5
r ! n r . a r e o b t a i n e di n ri Jrearboximidesare H :.'. CPB42'9 (1994)'
rcr. .rnd ketenebis(triC.laf\.
AfYo. \.)iz
H
gH /'
,n{ 48olo (> 99"/. ee)
Aldol condensation.e The formation of B-siloxy ester derivatives from ketene 'ilyl acetalsand aldehydesmay actuallybe an ene-typereactioninvolving silyl group migration. Michael reaction.ttt Using enonesas acceptors,enol silyl ethers as nucleophiles, rnd a chiral BINOL-TiO catalyst, the Michael reaction takes place at -78'C. The ee ralues range from moderate to highly respectable(36-90Vo). M. Terada, Y. Motoyama, and K. Mikami, TL 35,6693(t994). 'M. Terada, S. Matsukawa, and K. Mikami, CC 327(lgg3). K . M i k a m ia n dS . M a t s u k a w a , T L 3 5 , 3 l 3( 139 9 4 ) . 'K. Mikami, T. Yajima,M. Terada, E. Kato,andM. Maruta,TA5, 1087(1994).
44
Bis(acetonitrile)dichloropalladium(II)
tA.L.
C o s t a ,M . G . P i a z z a ,E . T a g l i a v i n i ,C . T r o m b i n i , a n d A . U m a n i - R o n c h i ,J A C S 1 1 5 ' 7001d993). oS. A o k i , K . M i k a m i , M . T e r a d a ,a n d T . N a k a i , f 4 9 , 1 7 8 3( 1 9 9 3 ) . 'c. E. Keck and L. S. Geraci, TL 34,782'7 (1993). 8 G. E. Keck, D. Krishnamurthy,and X. Chen, rL 35, 8323(1994\'K. M i k a m i a n d S . M a t s u k a w a ,J A C S 1 1 6 , 4 0 7 ' 7( 1 9 9 4 ) . l"S. K o b a y a s h i ,S . S u d a , M . Y a m a d a ,a n d T . M u k a i y a m a , C L 9 7 ( 1 9 9 4 ) .
itrile)dichloropalladium(Il).14,35-36; 15,28-29; 16,25- 26; 17,30-3 | Bis(aceton finds usein the prepaAllylic rearrangement. This suprafacialrearrangement oxides.2 and 6-hydroxyallylic phosphine rationof 4-acetoxy-2-alkenonitrilesr OAc
/w\./\ o
(MeCN)2PdCl2
cN
oAc
(MeCN)2PdCl2
rnrd\^/\
O
Bis(aceton itrile)chloronitropalledior Oxidative cyclization. Homoalll.l vertedto 7-lactolsrand 7-lactones.: req
T. M. Meulemans, N. H. Kiers, B. L. F.er -[994). : P. Compain, J.-M. Vatele,andJ. Gore.SL 9
-r'V"t,/f^"*
THF
'H. Abe, H. Nitta, A. Mori, and S. Inoue.C :J. Clayden and S. Warren, JCS(pt) 29t3 tll 'M. K i m u r a , H . H a r a y a m a ,S . T a n a k a . a n d 'P. A . v a n d e r S c h a a f ,J . - p . S u t t e r , M . G r c l l a n d M . P f e f f e r ,J A C S 1 1 6 ,5 t 4 3 ( 1 9 9 4 ) . '_A . D e g l ' l n n o c e n t i , A . C a p p e r u c c i ,L . B a r r (1994). oA. D u c h e n e ,M . A b a r b r i , J . - L . p a r r a i n . V M. Kosugi, T. Sakaya, S. Ogawa, and T. Mr
OAc
^t'n2HVV\ .r I
Bis(allyl)di.fr-chlorodipallad ium.
87"/"
The catalyst induces endo-trig cyclization of 2-hydroxyat room temperatureto afford 3-pyrrolines.' An oxidaderivatives 3-butenylamine o-allylbenzylaminesaoccurs when PhrP is added after of tertiary tive cyclization Cyclization.
Cross coupling,t Biaryls are otxarr rn the presenceof the palladium complcr vic-Bissilylation.2 Disilanes are sp r h e 1 , 2 - d i s i l ydl e r i v a t i v e s .
Allylic substitution.l Di-Boc-ail1L tates.The productsare convertedinto pr
complexation. NaN(Boc)2
^
aY'v t t \u
l
l
z
"{t,'"' \,,^YNME,
(M€cN)zPdcrz
.:.-NMe2
NaoAc / MecN
\\,". 'i/ 'oAc
Ph3P r'Ya ,; $,./r", I
I
'"?;I'
cl
86"k
Cross couplings. The catalyzed coupling of haloalkenes with organometallic reagentsgivesrise to variousfunctionalizedalkenes,includingenynes,s3-substituted 3-butenoicacids.6and 1.4-dienes.r
o o ll
,./"nou"
7)' Me3Si'
+
Aa,rn"
[[ .2' I
(M€cN)2Pdcl?
DMF.N2 rl,1h
z
fsien.
Me3Si-
64"/"
.--..------.--*\.^ r. a t !
1r'-t ?!:Pt
Many chiral ligands have been investigar lective sense.These bidentate ligands usn pair.n
Reductive cleavage of &(N-goc Using formic acid as hydrogen sourcc. conjugated and deconjugated esters. Th palladium.
Y. Hatanaka, K.-i. Goda,y. Okahara.andI -F. Ozawa,M. Sugawara, andT. Hayashi.O 'R. J u m n a hJ,. M . J .W i l l i a m s a, n dA . C . W 'B. M. TrostandM. G. Organ,.IACS116.t0
Bis(allyl)di-p.chlorodipalladiurn r - R o n c h i .J A C S 1 1 5 '
1 6 .1 5 - 2 6 : 1 7 .3 0 - 3 1 nJs use in the PrePa: : , . p h i n eo x i d e s . 2
45
'H. Abe, H. Nitta, A. Mori, and S. Inoue, CL2443 Ogg2\. :J. Clayden and S. Warren, JCS(PI) 2gl3 (lgg3). tM. K i m u r a , H . H a r a y a m a ,S . T a n a k a , a n d Y . T a m a r u , C C 2 5 3 1( 1 9 9 4 ) . 'P.A. v a n d e r S c h a a f ,J . - P . S u t t e r , M . G r e l l i e r , G . P . M . v a n M i e r , A . L . S p e k , G . v a n K o t e n , and M. Pfeffer, JACS 116,5143 (1994). tA. D e g l ' l n n o c e n t i , A . C a p p e r u c c i ,L . B a r t o l e t t i , A . M o r d i n i , a n d G . R e g i n a t o , I L 3 5 , 2 0 g 1 ( t994). oA. D u c h e n e ,M . A b a r b r i , J . - L . P a r r a i n , M . K i t a m u r a , a n d R . N o y o r i , 5 L 5 2 4 ( l g g 4 ) . 'M. K o s u g i , T . S a k a y a ,S . O g a w a ,a n d T . M i g i t a , B C S J 6 6 , 3 0 5 8 ( 1 9 9 3 ) .
-'
Ita' l|\
'
i
Bis(acetonitrile)chloronitropalladium(II)-copper(II)chloride-oxygen. Oxidative cyclization. Homoallylic and homopropargylicalcoholsare convertedto 7-lactolsrand 7-lactones,2 respectively. 'T.M. M e u l e m a n s ,N . H . K i e r s , B . L . F e r i n g a ,a n d p . W . N . M . v a n L e e u w e n ,T L 3 5 , 4 5 5 -41994).
CN
rP.
.:lr()n of 2-hYdroxY. r r r o l i n e s . rA n o x i d a 'r Ph'P is added after
c i ,r,:
I
C o m p a i n , J . - M . V a t e l e ,a n d J . G o r e , S L g 4 3 ( l g g 4 ' ) .
Bis(allyl)di-fr-chlorodipallad ium. cross coupling.' Biaryls are obtained from aryl halides and aryl(halo)silanes in the presenceof the palladium complex and KF. vic-Bissilylation.2 Disilanes are split and add to alkenes and alkynes to glve t h e 1 . 2 - d i s i l ydl e r i v a r i v e s . Allylic substitution.l Di-Boc-allylamines are readily obtained from allyl acetates.The productsare convertedinto protectedglycine esterson ozonolysis. NaN(Boc)z
\Aoo. > :
U
r
ru1ao.1, ""oi MeOH l6-/.
MeooC
ttlBocl2 95"k
Ph3P- MF
b -
600
86% ) & .\ J : ' L r ' \ u i t h o r g a n o m e t a l l i c c,-.: rr cny nes,t 3-substituted
l.ri
(-pa,ct \ , :-- ,
\
\
S
\lany chiral ligandshave been investigatedto assistthe substitutionin an enantioselectivesense.Thesebidentateligandsusually possessan N,p-,a-6N,.!-,7 or O,p-donor pair.n Reductive cleavage of B-@-Boc-aziridin-2-yl) a,B-unsaturated esters.e using formic acid as hydrogen source, the reductive cleavage gives a mixture of conjugatedand deconjugatedesters.The caralyst is bis(2-methallyl)di-p-chlorodipalladium. Y . H a t a n a k aK,. - i . G o d a ,Y . O k a h a r aa,n dT . H i y a m a , 2 5 0 , 8 3 0(11 9 9 4 ) . 'F. Ozawa, M. Sugawara, and T. Hayashi, OM 13,323'l(lgg4). R. Jumnah,J.M. J. Williams,andA. C. Williams,TL 34,6619(t993\. '8. M. Trost and M. G. Organ,JACStt6, t0320(t994).
l6
Bis(benzonitrile)dichloropalladium(II)
'P. 32' 566 (1993)' von Matt and A' Pfaltz' ACIEE a n d G ' H e l m c h e n 'T A 5 ' ^ ; ' P f a l i z ' C ' L e f e b e r 'T ' F e u c h t ' ; ' ; ; ' P. von Matt, o. Loiseliur' 573( 1994). J' M' J Williams'JCS(PI) -J.V. C G ' F r o s t 'C ' J ' M a r t i n ' a n d A l l e n , S . J . C o o t e ,G J ' D a w s o n ' 2 0 6 5( r 9 9 4 ) . '1. sL 551(1994)' c. fr"" ""d J' M J' Williams' " Y a m a m o t o 'S L 6 4 ( 1 9 9 5 ) ' A ' a n d S h i m i z u , I . A. Satake'
Bis(arenesulfonyl)methanes' under solidare obtained through alkylation Atdehyde syilthesis't Aldehydes l i q u i d b i p h a s i c c o n d i t i o n s f o l l o w e d b y r e d u c t i o n w i t h L i A l Hsynthon' 4andHg(Il)-promoted methanesare a formyl anion hydrolysis.Thus the bissulfonyl
R
I lll 'l
A
B ,.) f
?
Fo/ +
f
catalyst.
Ar'SO2N=XArn
sensitiveO-protectedT-hydroxyB-ketoestersrssimplified'usingtheadductsofthe alcohol as precursors' alkynoic esterswith propargyl
,",J
o ll
ill
'l'
Meo'')
o
PdClz(PhCN)z
o
r',t"o,&orHP PhH 60-650 8h
(no' OTHP
of allylic alcohols (e'g'' allyl alcohols'2 Umpolung Allytation of aldehydes with in the presence attack on aldehydesis realized isoprenol)and the ai'""t nutt"ophilic of (PhCN):PdClI and SnCl:'
(PhcN)2Pdcl2
RcHo - ,o')''y'
?
THF - H2O
OH rr ll I
/\)v
56-83%
are formed' a-Chloromethylene-7-lactones Cyclization of allyl propynoates'3'4 original substitution tnrru"n."d by additivesand the The nature oi tt" B_grouo',', pattern.
i
co (PrcN|fq
13' 34; l5' 29 Bis(benzonitrile)dichloropalladium(II)' other The selective cleavage(fbr which 'i'yl an'n't Cleavage "f p'"p";;;; useis (":1 in the presenceof other "'tn"" :,1"jtals) Pd(Il) reagentsare also effective) very preparation of the u.ing this methodology, the ful for syntheti" *un,p,irutionr.
NaO
f
ArSOzCl- ArI.5 This transformationrc and also LiCl and (lPrO)+Ti. Arenesulfonyl isocyanates.6 Arenesulfon diphenylselenideundergogroup exchangeurth
'Y.-P.WangandX Huang'YH 13'253(1993)'
^
CuCl2
cH{,,
X - - 1 ,n = 1 X = S e .n = 2
Imidazolidin-2'thiones.n Aziridines coo influence of (PhCN)zPdClu.
G .S . S a r i n ,7 L 3 4 ,6 3 0 9( 1 9 9 3 ) . ' Y . M a s u y a m aM, . F u s ea' n dY . K u r u s uC ' L ll99 t S . M a a n dX . L u , J O C 5 8 ' 1 2 4 5( 1 9 9 3 ) ' 'S. Ma andX. Lu, JOMC447'3O5(19931. 'T. Satoh,K. Itoh, M. Miura,andM. Nomura.SCj 'G. a n dL . I . S i m a n d iI,L 3 4 . 2 8 3 9r l 9 9 l r -G. B e s e n y e i S. Nemeth,andL. l. Simandi.fl !6' Besenyei, 'J -O. BaegandH. Atper,JACS116' 1220( l99r)
Bis(ben zyloxy)diethyla minophosph i nc. Glycosyl phosphites-' The diethylamtno rhuson reactionwith sugarsin the presenccof tormed.These productsare not only useful ar Jized to the phosphates,which are precunor \{. M. Sim, H. Kondo,andC.-H. Wong.JACSll!
Bis(bromomagnesium) sulfide. Sulfides. The reagent, prepared b1 satu uith anhydrousH25, reactswith organic halx JOCU2t' ll0] A. N. NodugovandN. N' Pavlova,
B i s ( b r o m o m a g n e s i u m ) s u l f i d e4 7 R
- . ' r t . r n d C . H e l m c h e n I' A 5 .
||.
I
cr cl
B Pdcr2(PhcN)2
lt/
, - i J \ 1 . J . W i l l i a m s ,J C S ( P I I
R{
f_\
CuCl2
04o)
cH3cN, Licl n,43-72h
o4o/
/--n
50-94%
d
) a'
. : n a l k v l a t i o nu n d e r s o l i d t lH. and Hg(II)-Promoted ,, n \ \ n t h o n .
Arsozcl - ArI.5 This transformationrequires znl2 or KI as iodide source, and also LiCl and (iPrO)rTi. Arenesulfonyl isocyanates.6 Arenesulfonylimino derivativesof iodobenzeneor diphenylselenideundergogroup exchangewith co in the presenceof the palladium catalyst. co (PhcN)2Pdct2
Ar'S02N=C=O
Ar'SO2N=XArn l l i r o' f, f - t
cH2ct2
-. .learage (for which other : . r h c r \ ( e . g . ,a c e t a l si)s u s e :hc preparationof the very 'J. u.in-qthe adductsof the
- .
X = 1 ,n = 1 X=Se,n=2
Imidazolidin-2-thiones.s
Aziridines condense with sulfur diimides under the
i nf luence of (PhCN)zPdClz. G. S. Sarin, TL 34,6309 (t993). Y . M a s u y a m a ,M . F u s e , a n d y . K u r u s u , C L l l g g ( l g g j , . 'S. M a a n d X . L u , J O C 5 8 , 1 2 4 5( 1 9 9 3 ) . 'S. Ma and X. Lu, JOMC 442, 305 ( 1993). 'T. S a t o h ,K . I t o h , M . M i u r a , a n d M . N o m u r a , B C S J6 6 , Z l 2 l ( 1 9 9 3 ) . -G. B e s e n y e ia n d L . I . S i m a n d i , T L 3 4 , 2 8 3 9 ( t g g 3 ) . G . B e s e n y e i ,S . N e m e t h , a n d L . L S i m a n d i , T L 3 5 , 9 6 0 9 O g g / ) . 'J.-O. B a e ga n d H . A l p e r , J A C S 1 1 6 , t 2 2 O( g 9 4 \ . .
oil
o ll
nt"o,.WorHP :. '
l -r_
69"k
u n g o f a l l y l i c a l c o h o l s( e . g ' ' -.. r. realized in the presence
o*il : I F
o *
Bis(benzyloxy)diethylaminophosphine. Glycosyl phosphites,t The diethylamino group of the reagent is exchangeabre; thuson reactionwith sugarsin the presenceof r,2,A-triazore,glycosyl phosphitesare iormed' These productsare not onry useful as glycosyrationagents, they can be oxiJized to the phosphates,which are precursorsof sugarnucleotides. M. M. Sim, H. Kondo,andC.-H. Wong,"/ACS11S,2260 il993).
56-83'/" Bis(bromomagnesium) sulfide.
or lJ:
are formed. l:rr Iene-7-lactones . Jnd the original substitution
sulfides' The reagent, prepared by saturating an ethereal solution of EtMgBr *ith anhydrousH25, reactswith organic halides to furnish sulfides. {. N. NodugovandN. N. pavlova, JOCU 29. I 103(l992).
4t
manganese(III) chloride [N,N'-Bis(3,5-di-/-butylsalicylidene)-1,2-cyclohexanediaminato(2-)l
Bis(/-butoxycarbonyl) oxide. IDi-t-butyl pyrocarbonate] Derivatization of amines and alcohols. Attachment of the Boc group to aryand BoczO.Both laminesr is achievedby reactionwith sodium hexamethyldisilazide nitrogen and oxygen atoms of hydroxylamine are derivatized in a biphasic system in the presenceof EtrN as base.2 Cyclic carbodiimides.s Bis(iminophosphoranes)behaveas nucleophilestoward Boc2O. After an isocyanate is formed, a Wittig reaction follows. Either an intramolecular or intermolecular process predominatesaccording to the influence of rins strain.
J. F. Larrow, E. N. Jacobsen,y. Gao. y. Flor
(-\ N=C=N: Boczo - DMAP
cH2ct2
N=c=No
rt.th
'lo"/.
' T. A. Kelly andD.W. McNeil,7L 35, 9003( 1994). I M. A. StaszakandC. N. Doecke,TL 34,7043(1993). tP. Molina,M. Alajarin,P. Sanchez-Andrada, J. Elguero,and M.L. Jimeno,JOC 59,7306 (1994).
N,O-Bis(f -butoxycarbonyl)hydroxylam ine. Synthesisof N-alkylhydroxylamines and hydroxamic acids,' N-Alkylation is conditions(96-98Vayield), whereasacyconvenientlyachievedunder phase-transfer The lation with an acyl chlorideproceedsin the presenceof EtrN in dichloromethane. Boc groups are subsequentlyremoved on treatment with trifluoroacetic acid. ' M. A. StaszakandC.W.Doecke,TL 35,6021(1994\.
[N, N' -Bis(3,5-di-r-butylsalicylidene)- 1,2-cyclohexanediam i nato(2-)] manganese(lII) chloride. Enantioselective epoxidation.' This effective catalyst (l) is readily prepared in a 70-100 kg scalefrom the resolveddiamine (with tartaric acid), the salicylaldehyde (from formylation of the phenol by Duff reaction), and manganeseacetate,followed by anion exchangeby treatment with aqueousNaCl.
Bis(chlorodibutyltin)
oxide. Diol monoesters.t l,n-Diacetates rr by transesterificationto methanol in rh effect arisesfrom cooperationof two difl l,rng-gh.ir diacetates(n > 5) the selcc cannotoperate.
J. Otera,N. Dan-oh,andH. Nozaki.f 19. -l
Bis(sym-collidine)iodine(I) perchlonrc Silylation.t Transsilylation from a { rodinationof the doublebond, renderingr .rs 2- iodomethyltetrahydrofuran). Iodolactonization.2 Medium-sized .rlkenoic acids is favored by the presencc Glycosylationr phenyl selenoghco
Dissacharidesare formed at room tempcr
C. Colombier, T. Skrydstrup, andJ.-M. &r B. SimonorandC. Rousseau, ,/OC59.59ll r l H. M. Zuurmond,P.H. van der Meer.p. A tl ran Boom,JCC 12, l09l (1993).
Bis(1,5-cyclooctadiene)nickel(0). 13. _15
t7.32
Bromoalkene t alkene cyclizatiot. lar cyclization,making methyleneazacrc
lut,r
l',1 manganese(Ill) chloride
Bis(1,5-cyclooctadiene)nickel(O)49
lla
tr|.-' ,i rhe Boc group to aryt h r . : : . i l a z i d ea n d B o c 2 0 .B o t h r o : . . r J r n a b i p h a s i cs y s t e mi n tRibofuranosides.s Starting from ribofuranoses and alcohols, the glycosidation is mediatedby a mixture of AgClOa and Lawesson'sreagentor Ph2Sn:S. ' T . N i s h i oJ, C S ( p t )l l l 3 ( 1 9 9 3 ) . rM. Kurobashi andT. Hiyama,TL 35, 3983(1994). tN. Shimomura CL l94l (1993). andT. Mukaiyama,
z\/\/\.1
-o
aG
T. Zevaco,E. Dunach,and M. postet.It .} :V. Le Boisselier, E. Dunach,and M. porrc
Bismuth. 13, 39 Carbonyl compounds and imines are attacked to give homoallylic alcoholsand amines by a mixture of bismuth and allyl bromide in acetonitrile.The presenceof BuaNBr is required, whereasMerSiCl and NaI are less effective. GenerAllylation.t
ally, the yields rangefrom 85 to95Vo.The use of tantalum insteadof bismuth works only for imines, and with lower yields. '
andJ.S. Sandhu,TL 34,7975(1993). P.J. Bhuyan,D. Prajapati,
Bismuth(Ill) chloride. 15, 37 Bismuth(Ill) chloride is an excellent catalyst for Thus t-butyl chloride is obtainedquantiwith chlorosilanes. chlorinationof alcohols Chlorination of alcohols.t
tatively at room temperature. Reduction of nitroarenes.2 This reagent in combination with zinc is a mild reducing agent, converting nitroarenes to azoxyarenes.
Bis(pyridine)iodine(I) tetrafluorobor Dimerization of 1-iodoalkynes.: l Iodination.2 Arenes undergo iodrn fluoromethanesulfonic acid may be uscd
J. Barluenga,.l M. Gonzalez, L Llorenre.e 'J. Barluenga, J . M . G o n z a l e zM, . A . G a r c r : 0 5 8( r 9 9 3 ) .
Bis(tetrabutylam monium)ceriu ml I V I
Oxidative cross-coupling,t a-Sran dation,and the resultingfree radicalsca .uch as silyl enol ethers and allylsilarrr
reaction.Note that a-germanylalkanoice the a-silylalkanoic estersdo not underso
lM. Labrouillere, andJ. Dubac,5L723(1994). C. Le Roux,H. Gaspard-lloughmane, 2H. N. Borah,D. Prajapati, J.S. Sandhu,andA. C. Ghosh,7L 35, 3167( 1994). ph{ Bismuth(III)
chloride-metal
*
R.M
cooEr
iodide.
Silyl enol ethers react with carbonyl acceptorsto give Bsiloxy ketonesand esters.rAs BiXr is also a catalystfor the replacementof B-siloxy groups, prolonged reaction times can be applied to prepare p-halo carbonyl comAldol condensation.
poundsdirectly.2The reactionis enhancedby ultrasound. 'C. Le Roux,H. Gaspard-lloughmane, J. Dubac,J. Jaud,andP.Vignaux,JOC 58' 1835(1993). 'C. Le Roux,H. Gaspard-lloughmane, andJ. Dubac,JOC 59,2238(1994).
Bismuth(III) mandelate-dimethyl sulfoxide. Epoxide cleavage. Carboxylic acids are obtained from this reaction.' It shows chemoselectivityin that alkenes and alcohols are inert. Bismuth(lII) acetateand oxide are not effective. In aryl epoxides, the presenceof electron-donating groups favor the oxidation.2
\'. Kohnoand K. Narasaka, CL 16g9( 199-1
Bis(tributylstannyl)acetylene.
Ethynylation of azaaromatics.t Afr :nateester,pyridine, quinoline, pyridazrn .\ the tin compound. a-Chloroethyl chl lct ivator.2
T. Itoh,H. Hasegawa, K. Nagata,M. Okade T. Itoh,H. Hasegawa, K. Nagata, M. Okadr.
Bis(tributyltin)acetylene 53
ln -.. rnd alcohols,the glYcosiIt\- r'l\ reagentor Ph2Sn:S.
zvvY
Bi mandelate
N"oo, DMSO, 800
507.
'T.Zevaco,E. Dunach,andM. Postel,TL34,2601(1993\. rV. Le Boisselier, E. Dunach,and M. Postel,JOMC482,ll9 (1994).
i r:. iiircked to give homoallYlic 1 l . r ^ l r r m i d ei n a c e t o n i t r i l eT. h e lr.: \:l
are lesseffective.Gener-
frii: -rn lnsteadof bismuth works
'J. Barluenga, I M . G o n z a l e zl ., L l o r e n t ea,n dP . J .C a m p o sA, C I E E 3 2 , 8 9 3( 1 9 9 3 ) . rJ. Barluenga, J. M. Gonzalez,M. A. Garcia-Martin, P.J. Campos,andG. Asensio,JOC 58,
t!
2058( l 993).
lc' :: .. an excellentcatalyst for r-t , . -hloride is obtainedquanti-
l -
Bis(pyridine)iodine(I) tetrafluoroborate -tetraf luoroboric acid. Dimerization of f-iodoalkynes.t Head-to-tailcoupling gives l,l-diiodoenynes. Iodination.2 Arenes undergoiodination in CH:Cl:. Trifluoroaceticacid or trifluoromethanesulfonicacid may be used insteadof tetrafluoroboricacid as catalyst.
- ^ r n r t r o nw i t h z i n c i s a m i l d
Bis(tetrabutylammonium)cerium(IV) nitrate. Oxidative cross-coupling.' a-Stannylalkanoicestersand amides undergooxidation, and the resultingfree radicalscan be trappedin situ by electron-richalkenes such as silyl enol eihers and allylsilanes.Thus 7-keto estersare accessibleby this reaction.Note that a-germanylalkanoicestersare lessreactivetoward the oxidant and the a-silylalkanoic estersdo not undergooxidation at all.
t?:
; .- : D.-'.
[ ) u b a cS, L7 2 3( 1 9 9 4 ) . 1994). - r 5 -. 1 1 6( 7
(BuaN)zCe(NOg)e
OTBS ph\
*
nsMAcooEr
tnM"ooa, K2CO3,MoCN 00, 2h
u. - -rrbonyl acceptorsto give Brlr.' : : the replacementof B-siloxy t :
::!'pare B-halo carbonYlcom-
lf :.
-:1J.
JOC 58' 1835(1993)' r1 , - .: P \ rgnaux, ( 1 9 9 4)' : l 1 8 i e Jr,'
tr.:.r'J irom this reaction.'It shows ar. :rert. Bismuth(lll) acetateand re..1.e of electron-donatinggroups
o
M=Sn, R=Bu M=Ge, R=Me M=Si, R=Me
44o/ 22"/" 0/,
Y . K o h n o a n d K . N a r a s a k a .C L 1 6 8 9( 1 9 9 3 ) .
Bis(tributylstan nyl)acetylene. Ethynylation of azaaromatics.t After activation of the system by a chloroformate ester,pyridine, quinoline, pyridazine, and analogousheterocyclesare attacked by the tin compound. o-Chloroethyl chloroformateis particularly effective as the activator.2 T. Itoh, H. Hasegawa, K. Nagata,M. Okada,andA. Ohsawa,750,13089(1994). 'T. ltoh, H. Hasegawa, SL 557(1994). K. Nagata,M. Okada,andA. Ohsawa,
54
Bis(tributYltin)oxide
39 Bis(tributyltin) oxide. 13,41-42: 15' r -i,--.BuaNF, benzyl-, allyl-, and alkynylsilanes by Cata|yzed Transmetallation., areconvertedtothetributyltinderivativesbythetinoxideinTHF.Yieldsareexcel. lent - (10 examPles,95-99Vo Yield)' ring opening to afford the stannyl ester i_ltt rr_z_ones., Diketene undergoes a tandem of an aldehyde and HMPA induce of p-stannyloxybutenoic acid' Addition aldolization and decarboxylation'
(BusSn)zO
:{Fo THF / Nz
r I I
l a.Z..,rosnBu3I T' It I O
lAu3SnO '
HMPA 400
0o. 10 min
2-Alkyl-4-oxopentanals'3
I
RcHo
Bis(2,2,2-trichloroethYl) azod Amination of arenes.' \[' electrophilic reagentfor manl a the amines by treatmentwith z
H. Mitchelland Y. Leblanc.JOC
Bis(trichloromethyl) carbonl Dehydration.' Aldoxrnrcr EtrN to give nitriles in good I t Chlorination of phosphint
Y\,' o
dichlorideson reactionwith trq aldehld to 1,2-dichloroalkanes, to isonitriles,ureasto carbodt
48-807o
derived from In the presenceof LiBr' the tin enolate
D. P. Sahu.IJC(B)32B.385( 199 tA. wells,sC 24, l'/15(l99at.
diketeneandbis(tributyltin)oxidereactswitha-bromoaldehydesinachemoselective bromine and decarboxylation' manner. It involves displacementof the
\
/ +
.V.N- Bis(trif luoromethanesul Aromatic chlorination. deficient arenes at room temPc
,Bt
cHo
1r:--,osnBua
(Bu3Sn)2O
l
0o, 10 min
l
l
o'snBu, o
LiBr rl, 24 h
CHO
O
S.V.S€rtd R. Yu.Garlyauskajte,
77"/"
l , 5 . D i k e t o n e s . o T h e d i k e t e n e - t i n o x i d e a d d u c t i s a u s e f u l M i c h a e l d o n not orthat do Note that simple stannyl enol ethers 1,5-diketones. give to enones with reacts of the o-stannyl group by the ester undergo the same reaction; thus the coordination carbonYl must be imPortant' oxide' as well as many other organMacrolactonization.s Bis(tributyltin) of ll-' l3-' 14-' 16-' and l7-membered otin(IV) compounds, catalyzetheformation in hot octane' The yields c'r-hydroxyalkanoates lactones from 2,2,2-trifluoroethyl range from 2l%oto SlVo' '8. P. Warnerand S. L' Buchwald,JOC 59' 5822(1994)' ' CL l2l9 (1993)' 21.Shibata,M. Nishio,A. Baba'andH' Matsuda ' JoC 59'486(1994)' H' Matsuda and 1M. Yasuda, A' Baba' r' Siiittt' M. Nishio, ol. Shibata,M, Nishio,A' Baba,andH' Matsuda'CC 1067(1993)' tJ. D. White,N. J. creen,andF' R' Fleming'?L 34' 3515(1993)'
Bis(trif luoromethyl) telluril I Trifluoromethylation.' methylation.Three different P A renethiols are S-tri f luorol
and S.V.Pazenok. D. Naumann,
1.2-Bis(trimethylsiloxy)cYch I, I - B utanediacylat ioa. ranedionesin one Pot BF, etlx cyclobutenewith acetalsor kc \mall amount of water after tl :rnd to render the reversible n Jouble bonds disfavor the pro
: I * nthesisare relatedto its complexatton br reductionof CoBrz with Zn dust uo rcetylene.Pauson-Khandreactionscan
H. K. Patney,TL 35, 5717(1994). 'V. Periasamy, M. R. Reddy,and A. Dcreg
Cobalt(Il) chloride. 14, 99; 15, 97-9t Allylation of 1,3-dicarbonyl cosV rrotesthe allylation of 1,3-dicarbonllcc Ilnsymmetrical suffides.2 RSH -
p-Acetamido ketones.t A rhree-c rn aldehyde, and acetonitrile appears r hldration of nitrilium species,which rs r
Cobalt(Il)chloride 107 i \ l : : X . r r . M . E . R e u m ' J ' H . R y a n ,a n d K ' A '
tre::iJll\
I
p r e p a r e dat low temperatures
Cobalt(II) acetylacetonate.17,87 canbe rendered enantiose[4tt+2tt+2tt]Cycloadditions.t Suchcycloadditions ligand. lectiveby addinga chiralphosphine
r - '
. rn CH:Cl: with uttrasoundirradiad r :rrton or convertedinto CrOz(OBu')z r.: : - : - 1.5-diol for other oxidations' LTt
Br;
'J. C o s s ya n d A . B o u z i d e ,C C l 2 l 8 ( 1 9 9 3 ) . rS.-1. M u r a h a s h i ,T . N a o t a , a n d N . H i r a i , J O C 5 8 , 7 3 1 8( 1 9 9 3 ) .
h.*1
Co(acac)2 F.PROPHOS Et2AlCl/PhH 66o/o (72'h ael
i
i r : - t l i r e d i n s i t u b Y Zn reductionof hYare : \ H . C l . F u s e d rneso-aziridines r.
-VNHCOOBUI I
-,.
y-Lactones from tetrahydrofurans.2 Oxidation with molecular oxygen is accomplishedin the presenceof an a-diketone. Epoxidation.t Oxygen is used as oxidant, and propanal diethyl acetal acts as a cooxidantin the presenceof 4A-molecular sieves.Silyl keteneacetalsgive a-siloxy estersas a resultof rearrangement. W. Tam,andC. Sood,JOC 58,4513(1993). M. Lautens, '8. Hata,T. Takai,andT. Mukaiyama, CL l5l3 (1993). 'K. CL 1579(1993). Yorozu,T. Takai,T. Yamada,andT. Mukaiyama,
e
t :
5'61" (87olo ee)
, ,-.
Drr.3:imrnes can add to a proximal double L-:.r
Cobalt(II) bromide-silica. Dithioacetization.t The reaction is usually complete at room temperature within a few minutes. Most uses of dicobalt octacarbonyl in organic In situ generation oI CodCo)*' synthesisare relatedto its complexationto triple bonds.The complex may be formed by reductionof CoBrz with Zn dust under a CO atmospherein the presenceof an acetylene.Pauson-Khandreactionscan be carried out subsequently.
llr
H. K. Patney,TL 35, 5'717(1994). : M . P e r i a s a mM y ,. R . R e d d ya, n dA . D e v a s a g a y a r a j , 7 5 0 , 6(915959 4 ) . \ --
+ r'N
^
\.,-r\
\
6O96(95:5)
rr j;rlron of alcohols requires Co(OAc)z as ilar. r'. \'ields of acids or ketones are excel-
Cobalt(Il) chloride. 14, 99: 15, 97-98 Allylation of l,3-dicarbonyl compounds.t A catalytic amount of CoClz promotesthe allylation of 1,3-dicarbonylcompoundswith allyl acetatesin high yields. Unsymmetrical sulfides.2 RSH + F(X - RSR'. p-Acetamido ketones.t A three-component condensation involving a ketone, .rn aldehyde, and acetonitrile appears to involve aldol and Michael reactions and hydrationof nitrilium species,which is quite unusual.
lOt
Cobalt(II) chloride-oxySen
o
o
O
CoC12
R'\
H,
I Rl
B2
NHAC
i l l
+
R-^'Y'\R2 I Rr
CH3CN,AcCl
26-787o
'G.c. Maikap, M . M . R e d d yM , . M u k h o p a d h y aBy.,B h a t i aa, n dJ . I q b a r r, 5 0 , 9 1 4 5( 1 9 9 4 ) . rS. Chowdhury, P.M. Samuel,L Das,andS. i.oy, CC tgg3(lgg4). rB. Bhatia, M. M. Reddy,andJ. Iqbal,CC 713(igg4).
Cobalt(II) chloride-oxygen. oxidation of aldehydes. In the presenceof butanal, aromatic aldehydes undergooxidativecoupling at room temperatureto give benzils (g examples,62-7Svo).1 The sameoxidationcan be diverted to the carboxylic acid on additionof Ac2o to the reactionmedium. A similar processfor the oxidationof secondaryalcoholsis catalyzedby a cobaltdisalencomplex.2 Oxidative condensation of aldehydes and alkenes.l
o ll \rAH
CoCl2-02 /MeCN +
/tcoor"
O
T. P u n n i y a m u r t h y ,S . J . S . K a l r a , a n d J . l g b o l - s .J .
S . K a l r a , T . P u n n i y a m u r t h y ,a n d J . l q b t t . B h a t i a , T . P u n n i y a m u r t h y ,B . B h a t i a , a n d J ' T .P u n n i y a m u r t h y , B. Bhatia,and J. Iqbal. I! 'P. Li and H. Alper, CJC 71, 84 (1993). 5.
C o p p e r .1 5 , 9 9 ;1 6 , 9 5 o-Halophenylcopperreagents.t o-l* copperreagents,which can be usedat roo groups. N-Phenylanthranilic acids.2 Coppc halobenzoic acidsby aniline may be pcrfo Ullmann coupling.3 This classicrc: sis. Unsymmetricalbiphenylsare obtairs ;alicyl alcoholunit), thusrenderingthc ret a-Amino estersand ketones.a c-Dn aminesin refluxingtolueneunderthc inf} ketonesor estersin onestep.A Stevensree \uch products.
OAc
o
AczO, rl
il F1/"
..
+ P?rCH2rllr2 tl N2
Epoxidation and benzylic oxidation.a
tn.4rn
CoCl2-02 /MeCN
tnhrn 91./"
f'Yo*l"n VOH
Allylation of active methllcnc co.Fr uredto promoteC-allylation.
G . W . E b e r t , D . R . P f e n n i g , S . D . S u c h a n .r n d l R. F. Pellon, R. Carrasco, and L. Rodcs. SC l! \l Takahashi,T. Oguku, K. Okamura, T. Dt
rt
tsPrCHO
tcs(Pr) t473(t993).
'F
G. West,K.W. Glaeske, andB. N. Naidu.S 9 J B. Baruahand A. G. Samuelson. /yJClt. 96t
Clea vage of I, 3 - diox olan es.s
R' coet2-znct2to2
^ ) o -\ I n^d
)-R'
D M E ,8 5 - 9 5 .
HCOO- ,/
o il
R^o
\
\
/-R'
Copper(II) acetate. Dehydrogenation of carboxamido c ut 1 the dehydrogenation,which can also bc r
CoPPer(II).c€tete109
NHAC
O
i
l
r'T*'
> :'. :r:
l
B1
'T. Punniyamurthy'S.J. S. Kalra, and J' Iqbal,TL 35' 2959(1994)' tS. J. S. Kalra, T. Punniyamurthy,and J' lqbal, TL 35' 484'l(1994)' 'S. B. Bhatia,andJ' Iqbal'f49' 6l0l (1993)' Bhatia,T. Punniyamurthy, 'T. Punniyamurthy, B' Bhatia,andJ. Iqbal,TL34,4657'4003(1993)' 'P. Li andH. Alper,CJCTI' 84 (1993).
26'78'/o
(1994)' a : . r t r r . a n d J . l q b a l ,I 5 0 , 9 1 4 5
t! :
:' ..-
'ut .'nno''
uns
HCOOJ
!d
o I
-'
^,,\n h
Fl'
\ rR' v
compounds.5 A mixture of cu and cucloa is
TL34'22'19(1993)' c W. Ebert,D. R. Pfennig,S.D. Suchan'andT' A' Donovan' (1993)' 144'l 23' SC R F. Pellon,R. Carrasco,and L. Rodes, and T' Iwasaki' T. Oguku,K. Okamura,T' Da-te'H' Ohmizu' K' Kondo' \1. Takahashi, tcs(PI) t4'13(t993). 'F G. West,K.W. Glaeske'andB' N. Naidu,S 9"17(1993)' N'/Clt' 961(1994)' I B. BaruahandA.G. Samuelson,
91%
t-
7oo/o 63"/o
Copper(II) acetate. Dehydrogenationo!carboxamidocnamincs.|Conjugatediminesareproduced manganeseacetate' 1 the dehydrogenation,which can also be effected with
ll0
Copper(I) bora(trisdimethylpyrazole)
complex
,,?-
ra
s
P1:
d
Ph
R=R'=Me R=Ph,R'=H
Addition ond condcnsation reactions. afford homologsof dimethylitaconate.a
\ ' . R a t o v e l o m a n n a n aY , . Rollin, C. Gebehcnm ,1994). '\. O n o , H . K a t a y a m a ,S . N i s h i y a m a ,a n d T e S . B r a v e r m a n ,D . G r i n s t e i n , a n d H . E . G o r r l r c b 'R. B a l l i n i a n d A . R i n a l d i , T L 3 5 . 9 2 4 7( t 9 9 t t F. G. West and G. U. Gunawardena. JOC St. fi 'M.-H. F i l i p p i n i a n d J . R o d r i g u e z ,C C 3 3 r t 9 9 t
and dimethyl
maleate
J. Vallgarda, U. Appelberg, I. Csoregh, and L' C . C a t i v i e l a ,M . D . D i a z d e V i l l e g a s , a n d A . I
t
Diazomethane
.\eJ h\ the presenceof PhrP (ofr.::re attack of Me2Zn on the
/
rNOe
,-YcooMe
DBU
acooMe ll \cooM"
- '
121
\cooM"
MeCN 15min
93v" i r - , i r - ] l . 1 5 8 7( 1 9 9 2 ) . x r c 5 L ' 1 1 0( 1 9 9 4 ) . CB 126,459(1993)' rn.:ir Schwarze,
4-Hydroxy-2-cyclopentenonesreact with diketene under the influence of DBU to which is the result of O-acylation,intramolecugive 4-acetonyl-2-cyclopentenones,s lar Michael reaction and elimination. An unusual condensationreaction of cyclic p-keto estersand araldehydesgives the 7-arylidenederivatives.'
:r;e.lent catalyst for the condenp,Je.rncludecinnamaldehYdeand
97: 93"/' (E)'hidazone-> 42"/"
' a-vinyl-B-hydroxyl F . : . . 1 r - h ld e s p r o v i d e 1 , 3 d ienes' The dehydra,f,.-. n.'Vhonyl-
+
> 99:< 1 < 7:> 93
JOC 58' 7638 (1993)' K. Maruoka, M. Oishi, and H' Yamamoto'
(DAST)' 13' I l0-l l2; 16' 128-129 Diethylaminosulfur trifluoride 2-Fluoronitriles are proR-eplacementof oxygen functionality by fluorine' acyl cyanides give a'awhile ethers,r duced from a-cyanohydrins or their silyl dif luoronitriles.2 convertedto trifluoromethylalkenes'l Terminally difluorinated allylic alcoholsare
Et2NHSF3 CH2Cl2 - 700 -> 00
9!:
from Et' AlCN preleren*d.: , .rrnide ion the induction arises from . -t *..,ric
'
'
o ./ ' 9 N -_s. ' N ' J. \ph
Ar
H
,ao,o(ss:sF = 70:30)
may be performed with a-Fluorination of thioethers.a This transformation DAST alone or in combinationwith SbClr' (1993)' U. Stelzerand F. Effenberget,TA 4' 16l : E. BartmannandJ. Krause,JFC 61, I l7 (1993)' 'F. ' JFC 62, 183(1993)' TellierandR. Sauvetre 'M. J. RobbinsandS.F. Wnuk,"IOC58' 3800(1993)' Diethyl (1,3'butadien'2'yl) phosphate' Diels-Alderreaction.|Thesubstituteddienereactswithdienophilesinthe presenceofaLewisacid.Thestabilitytowardsacidsmakesiteasiertohandlethan rhe corresponding alkyl and silyl ethers' CJC 72' 2163(1994)' H.-J.Liu, W. M' Feng,J. B' Kim, and E' N' C' Browne'
r,
. - 1 5 9. 3 5 1 ( 1 9 9 4 ) .
lpiperidine'
under ---'^"?d COnVert( to indoles lh\.::J1ones are
l.:
amide'Notably ,i. it"aeredaluminum
hYdrazones' or:.i rration of the
Diethyl carboxymethylphosphonate' The phosphonoacetic acid underI-(Dialkylamtnomrinyqiinylphosphonates't Elimination of the secgoestwofold Mannich ,eaction tl giue the vinylphosphonates. primary adductsoccurs in situ' ondary amine reactant and COz from the
136 Diethyl methylphosPhonate
product, a triply functionalized compound i phosphonateare conceivable.
o (CHzO)n
(EtO),P'l\cooH ' '-tl RR'NH,PhH,^
(EIO\2P,qt I \..R
o
N I
Ap
R'
l \
29-921"
lH. Krawczyk,SC 24,2263(1994).
Diethyl chlorophosPhate. from Claisen rearrangement.t The quenching of the lithium enolates derived claisen for propensity allylic acetatesresults in enol phosphates,which show a higher be used rearrangementthan ketene silyl ethers. The mixed anhydride products can directly to generatecarboxylic acid derivatives'
o
o r-i.-.i-ar o|/b HO@.@{
B. Bonnet,Y. Le Gallic, G. Ple, and L. Duhem 'W. S. Shin, K. Lee, and D.Y. Oh, IL 36. 281 r I L D e l a m a r c h ea n d P . M o s s e t .J O C 5 9 . 5 4 5 . 1r l 9
Diethyl methylsulfonylmethylphospboo Vinylsulfunes.r Bothlithiationandco ultrasound. H. El Fakih,F. Pautet,D. Peters,H. Fillion.rr
oPo(oED2 I
y'-q.,
LOA:
crPo(oED2
EtgN- MeOH
Diethyl oxalate. Isatins.' These compounds are ob(e \-Boc anilines with diethyl oxalate follorrc
cHct3
)\:,/(
650
HMPA
77./"
P. Hewawasam and N. A. Meanwell.fL 35. 710 r R . L . F u n k ,J . B . S t a l l m a na, n dJ .A . W o s 'J A C Sf f s ' 8 8 4 7( 1 9 9 3 ) '
Diethyl methylPhosPhonate. in situ 1,1-Diiodoalkenes.t Diethyl diiodo(lithio)methylphosphonate is formed can also products condensation from MePO(OEt)r, LiHMDS, and iodine. The Horner be dehydroiodinated to give iodoacetylenes. (E)-Atlytic amines.2 Reaction of the lithiated methylphosphonateester with a with an nitrile, followed by addition of an aldehyde,furnishes a conjugatedimine amine. allylic gives the (e.g., NaBH+) with (E)-configuration.Immediate reduction
Diethyl phosphite. Aryl phosphonates.t Phosphite anroo DMF. Arylphosphonate esters are obtaincd Cyclic p-keto phosphonates.t A ncnitro epoxideswith diethyl phosphiteand r
o:"'
NeH - Df
(ElohPOH
o
BuLi,THF, -78o,t h;
il
(Eto)eP-"". PhcN, -780-> 50,t h; RCHO, -5o -> rt, 30 min
i
*".]
L-+*l
NaBH./MeOH
TN,
78o,1h->rt,1h
R/\"\Ph
83-85%(overallYiold)
Functionalized p-keto phosphonates.l lNote: Dimethyl methylphosphonate' After which should have exactly the same reactivity, is described in the cited report') of the esterification reaction of the a-lithio derivative with succinic anhydride and
a-Amino phosphonic esters.t A verr :hese phosphonopeptideprecursors involrer
rldes at 60"C in an ethanolicmedium conrr Reductive deconjugation ol 2-broto :nvolvesMichael addition, debromination rrnetic protonationofthe esterenolates.Trt : he reaction.
Diethylphosphite 137 product,a triply functionalizedcompoundis obtained.various syntheticusesof this phosphonateare conceivable.
o l l rEtO\zP:,4 r
,
I
\N-'
e
ot l
o
I
A t o
R'
Yo
29-92v"
Li _ P\-OMe OMe HOOC-COOH
o i
o l
t
l
--\_.Pr-OMe OMe I-cooH
'B. Bonnet,Y. Le Gallic, G. Ple,and L. Duhamel,S l07l (1993). tWS. Shin, K. Lee,and D.Y. Oh, TL36,2Bt (tggs). rl. D e l a m a r c h ea n d P . M o s s e t ,J O C 5 9 , 5 4 5 3 ( 1 9 9 4 ) .
rn-i : lhe lithium enolatesderived from hr-: .:ou a higher propensityfor Claisen ; :- '.:J anhydride products can be used \4.
Diethyl methylsulfonylmethylphosphonate, (EtO)rP(O)CHrS(O)rCHr. Vinyl sulfunes.' Both lithiationandcondensation with ketonesarepromotedby ultrasound. 'H. El Fakih,F. Pautet, D. Peters,H. Fillion,andJ. L. Luche,SC 24,3225(tgg4\.
P: ::.: t:
COOMe
E t 3 N- M e o H
I -.-1\
/\z\
cHcl3
I
Diethyl oxalate. Isatins.' These compounds are obtained by interception of the o-lithiated N-Boc anilines with diethyl oxalate followed by acid treatment.
650 83o/o
'P. Hewawasam andN. A. Meanwell,fL 35, 7303(1994). 5 l l 5 . . j - r1 9 9 3 ) .
is formed in situ Ih: :rc'thrlphosphonate can also products tr H rner condensation I
Diethyl phosphite. Aryl phosphonates.t Phosphite anions react with diaryliodonium salts in hot DMF. Arylphosphonate esters are obtained in 79-93Vo yield. Cyclic p-keto phosphonates.2 A new synthesis involves the treatment of anitro epoxides with diethyl phosphite and a base at room temperature.
ester with a l:r- ;led methylphosphonate with an imine lc :::'ntshes a conjugated amine' allylic the t * rrh NaBH.r)gives
'
='
-78".th->rt,th
R/,,.yPh
83-85%(ov€rall Yield) \.,rer Dimethyl methylphosphonate' r. rr:. .. .Jescribedin the cited report') After r-:::, .rnhvdrideand esterificationof the
(Y"
(Eto)2PoH
YPO(OEt)z
oT'
8O7o
T*,
NaBHy'MeOH
NaH . THF
a-Amino phosphonic esters.3 A very simple procedure for the preparation of these phosphonopeptideprecursors involves admixture of the phosphite with aldehydesat 60'C in an ethanolic medium containing NHaOAc and 3A molecular sieves. Reductive deconjugation of 2-bromo-2-alkenoatcs.a The process probably rnvolves Michael addition, debromination, and phosphite elimination prior to the kinetic protonation of the ester enolates.Triethylamine is required as baseto promote rhe reaction.
13E 2,2-Difluorovinyllithium and isoquinolines.5 Diethyl [(triphenylphosphoranylidene)aminolphosphonateis generatedfrom l-(triphenylphosphoranylidene)amino-methylbenzotriazole by reaction with diethyl phosphite anion. It undergoestypical Horner 2-Azadienes
reactions.
Diiodomethane. 13, ll3-115, 275-276: tC Ring expansion of silacyclobutanct. LDA-CH2I2 inserrsinto the cyclic C-Si bo have found some interesting synthetic applr
' 2 . - D . L i u a n d Z . - C .C h e n ,S 3 7 3( 1 9 9 3 ) . t D.Y. Kim and M. S. Kong,ICS(Pl)3359(1994)' rH. Takahashi, S 763(1994)' N. Imai, K' Onimura,andS. Kobayashi' M. Yoshioka, oT. Hirao,K. Hirano,andY. Ohshiro,BCSJ66,2781(1993). s A . R . K a t r i t z k yG J . J i a n gJ, O C5 9 ' 4 5 5 6( 1 9 9 4 ) . , . Zhang,and
Diethyl phosphoramidate. to acrylic esters in B-Amino esters.t The reagent is a Michael donor that adds free amines are liberThe toluene. in refluxing BuaNBr and KzCOr presence of the temperature. at room in benzene HCI with adducts Michael the treating ated on rK. Osowska-Pacewicka, S. Zawadzki,andA.Zwierzak'PSSE2'49 (1993)'
cnr+ j lil
Mez
&
Simmons-Smith reaction. Asymnnr containing a free hydroxyl group ar C-l rr elucopyranosides2 and their a-o- analogs'h cvclopropanes. (OBn
BsPSlVo\71,,n jg OH
Diethyl (trichloromethyl)phosphonate. Alkylphosphonate esters.t The carbanion generatedfrom dechlorination with BuLi condenseswith aldehydes(and some ketones). Catalytic hydrogenation of the (chlorovinyl)phosphonateproducts affords phosphonates.
ll#.71
o{r',
Ehan
o{*
'G.T. Lo*en and M. R. Almond,JOC 59,4548(1994).
Dif luoroiodomethane. A practical preparation of HCFzI is by reaction I,I-Difluoro-2-iodoalkanes.t of FSO:CFzCOFwith KI in MeCN between 30 and 40"C for 30 min. The iododifluoromethylationof alkenesis initiated by sodium dithionite. 'P. Cao,J.-X. Duan,and (1994). Q.-Y.Chen,CC'13'7
2,2-Difluorovinyllithium. a,B-Ilnsaturated acids and derivatives.t The adducts with carbonyl compounds are unstable.on treatment with HzSOa , HuSOr-MeOH,and EI2NLi-THF they are transformed into the unsaturated acids, methyl esters, and diethylamides' respectively.
Ph
F2C=CHLi
"x:
THF - EtzO -1000
'F.
T e l l i e ra n d R . S a u v e t r e , T L 3 4 , 5 4 3 3( 1 9 9 3 )
CFz
H2SOa -150
Ph
/-t"oor.',
An allylic alcohol may undergoan as\m ,.f a chiral ligand (e.g., a tartrate ester)to rl Trimethylaluminum can serve the sanE :odomethanefor cyclopropanation.5
Homologation of allylic alcohols.6 TL .rlic alcoholsbecomesa minor pathwa\ slr *hile using CH2IrEt2AlCl as reagents.Hoa
Methylenation of ketones.T The comb .i methylenatingagenr.The Wittig-like rcr iead are found to suppressthe reactivirl. of i :he Simmons-Smith reaction)is recovercdI Methylene homologation of vinylcq 'rhich undergotranspositionalalkylation.
&"" lc'r"ztr
RO€ -aC -> .r
Dliodomethane 139
l, : : rohenylPhosPhoranYlidene)e.9h,,ranylidene)amino-methylor: l: undergoestyPical Horner
Diiodomethane. 13, ll3-115, 275-276;16,184-185;17,155 Ring expansionof silacyclobutanes.tThe lithium carbenoidgeneratedfrom LDA-CH212 insertsinto thecyclicC-Si bondto give2-iodosilacyclopentanes, which havefoundsomeinterestingsyntheticapplications. cH2t2/ LDA JI
f. ^rrashi,S 763(1994).
Mez
THF, .78O
\^.,r-t 5l
Mez
Ar
837o
9*:
xr: rhat addsto acrylic estersin rrnc The free amines are libern/ene at room temperature. p r . s : . a 9( 1 9 9 3 ) .
Simmons-Smith reaction. Asymmetric methylene transfer to allyl glycosides containing a free hydroxyl group at C-2 arises from its directing effect. Both B-lglucopyranosides2 and their a-o- analogsrhavebeenexploitedfor the accessof chiral cyclopropanes. ,-oBn
BgPSlVorz\Ph OH
.rr:.J from dechlorinationwith I Crtalytic hYdrogenationof the
;;
(OBn
eno-$-Q "6^,oryor}",'n
OBn Et2Zn cq2l2
D3te'
lgrrJit()n of HCF2I is bY reaction at r'(. tor 30 min. The iododifluoht.,n:lc'.
'hc
rJducts with carbonYl comH SO.-MeOH, and EtzNLi-THF mct:\l esters,and diethYlamides'
-:*.
Et2zn
\--/ t"oo"
An allylic alcohol may undergo an asymmetric cyclopropanationoby attachment of a chiral ligand (e.g.,a tartrate ester)to the derived zinc alkoxide. Trimethylaluminum can serve the same role as Zn-Cu or Et2Zn to activate dirodomethanefor cyclopropanation.5 Homologation of allylic alcohols.o The Simmons-Smith reaction of certain allvlic alcohols becomes a minor pathway when they are treated with EtrAl/Et2AlOEt while using CH212-Et2Alclas reagents.Homoallylic iodidesare obtained. Methylenation of ketones.l The combination Zn-TiCla transforms CHzlz into r methylenating agent. The Wittig-like reaction is acceleratedby PbClr. Traces of lead are found to suppressthe reactivity of Zn toward CH212,but the reactivity (for the Simmons-Smith reaction)is recoveredby adding MerSiCl. Methylene homologation of vinylcoppers.s Allytmetat species are formed, *hich undergotranspositionalalkylation.
lCHzznl BCHO -400-> d
o (Y \-f-.R
,6"
0.5 h
80-91"/"
140 Diisobutylaluminum hYdride (1993). 'K. M a r s u m o t o ,y . A o k i , K . o s h i m a , K . U t i m o t o , a n d N . A . R a h m a n , T 4 9 , 8 4 8 ' 7 tA. B. Chareue and B. Cote, JOC 58,933 (1993). r A . B . C h a r e t t e ,N . T u r c o t t e , a n d J . - F . M a r c o u x , f L 3 5 ' 5 1 3 ( 1 9 9 4 ) ' nY. U k a . , i ,K . S a d a ,a n d K . I n o m a t a , C L 1 2 2 7 ( 1 9 9 3 ) . tJ. M . R u s s oa n d W . A . P r i c e , J O C 5 8 , 3 5 8 9 ( 1 9 9 3 ) ' o Y. Ukaji and K. Inomata , cL 2353 (1992). (1994)' tf. t u t u i , T . K a k i u c h i , Y . T a k a o k a ,a n d K . U t i m o t o ' J o C 5 9 , 2 6 6 8 ' 2 6 7 1 s A. Sidduri, M. J. Rozema, and P. Knochel ' JOC 58,2694 (1993)'
Diiron nonacarbonyl. 13, 320-321; 15, 334; 16' 351-353 Activation of allylic ethers. An allylic ether 7 to an electron-withdrawing group is activatedby forming the Fe(CO)+complex. on acid treatment ionization towards o."urc to generatethe allyl cation (still complexedto iron)' which is reactive substitution The etc.r enolates, ester malonate ethers, enol silyl as such nucleophiles
'S. Kikooka,M. Shirouchi.and Y. Kr : C . C a i n e l l iM , . P a n u n z i oM. . C o n r e 3809(l993). 'M. Lautens,P. Chiu,andJ.T.Colrrc 'M. Hayashi,T. Yoshiga,K. Nakarao 'J. M. ChongandJ. Johansen, fL 35. ^J. P. Marino and C. R. Hurt, SC 2f. 6 'D.J. K r y s a nS , C 2 4 , 1 5 8 9( 1 9 9 4 ) .
is stereoselective.2 'T. Zhou and J. R. Green,TL 34' 4497(1993). 'D. Enders,B. Jandeleit,and G. Raabe,ACIEE 33' 1949(1994)' 17' 123-125 Diisobutylaluminum hydride. 13, ll5-l16; 15, 137-138;16, 134-135; esters can of products reduction DIBALH The amines. and Monosilyl acetals those TMSoTf-pyridine'and with treatment by acetals be convertedinto monosilyl reagents'2 organolithium of addition the of nitriles into amines by unit. Opening of oxabicycles.3 The S7y2'reduction opens the 2,5-dihydrofuran This transformation. the assist to is required endo-oH Usually the presenceof an methodisapp|icabletotheelaborationoftheCrr-CzlSegmentofionomycin.
tsBu2AlH hexanes, a
837" Specialpreparations. a-Trialkylsiloxy aldehydes4and l-tosyloxy-2-alkanolss havebeensynthesizedusingDIBALHreductionofcyanohydrinsilylethersand epoxytosylates'respectively.Indolesand(Z)-allylicalcoholsareacquiredafter a-hydroxy simple manipulationsof the primary reductionproducts of nitriles and
Diisobutylaluminum hydridc-d Reduction of a-sulfinyl tao added to the medium. The relarrv opposite to that obtained withour t instead of ZnCl2.1
J .L . G . R u a n oA, . F u e r t ea, n dM . C I ' A . B . B u e n oM , . C . C a r r e n oJ,. L . G . I ( 1994). 'G. G u a n t iL, . B a n f i ,R . R i v a ,a n dM ,
Diisopinocampheylborane, ( Ipc! Chiral 1,4-diols.t Reactionol a rapid hydroboration, which is foll An alternative method2comprt! results in cyclic oxaboranes, tnra Prior to the oxidation the carbon c BuLi. The diols have been conw -piperidines.
esters,respectivelY.
anolz-/cru VNHz
iBu2AlH/ PhH, 0o; KF/ H2O,0o
""olzl{ \.,4N
o
"A"
6,:* THF..ltr
8H3. Sila M€Ol.l
Diisopinocampheylborane, (Ipc)zBH,end B derivatlves l4l I. Rrhman, T 49,8487 (1993).
\ i
..
olo
eg_lt.
FBu2AlH, -78o
,L-{
PhgP=CHR,2So
53-747" Or 5e 1668.2671 (1994). '.ri 9:
l::
i:.1
ts: 1 r\) an electron-withdrawing lcr ()n acid treatment ionization r, l:, 'n r. which is reactive towards !tc: in,llales, etc.r The substitution
9
-,:
'S. Kikooka,M. Shirouchi,andY. Kaneko,TL 34. l4gl ,lgg3\. rG. c a i n e l l i ,M . P a n u n z i oM, . c o n t e n t oD, . G i a c o m i n E i , . M e z z i n aa, n dD . G i o v a g n o lri4, 9 . 38090993). tM. Lautens, P. Chiu,andJ.T.Colucci,ACIEE12,2Sl (1993). {M. Hayashi,T. Yoshiga, K. Nakatani,K. Ono,and N. Oguni,TSO,2g|l (lgg4). 'J. M. Chong andJ. Johansen , TL 35,7lg7 (lgg4). nJ.P. MarinoandC. R. Hurt, SC 24,839(lgg4). 'D. J. Krysan,SC 24, t58g(tgg|).
lr- l.tl't:16, 134-135;17,123-125 of esterscan ,H :rJuctionProducts . I \ { S O T f - P Y r i d i n e ' atnhdo s e u ::
Diisobutylaluminum hydride-zinc chloride. Reduction of a-sulfinyl ketones. chelation control operates when Zncl2 is added to the medium. The relative configuration of the resultant alcohol is often oppositeto that obtained without the metal salt.r'2Magnesiumbromide can be used instead of ZnCl2.3
tt: j :I reagents.2 n : r 1 . t h e 2 . 5 - d i h Y d r o f u r aunn i t . r . : . ' r : t t h e t r a n s f o r m a t i o nT' h i s -( . i S m e n lo f i o n o m Y c i n .
'J. L. G. Ruano,A. Fuerte,andM. C. Maestro,TA S, 1443(lgg4). tA. B. Bueno, M.C. Carreno,J. L.G. Ruano,B. pefia,A. Rubio,andM. A. Hoyos,I50, 9355 ( 1994). 'G. cuanti, L. Banfi,R. Riva,and M.T. Zannetti,TL34,5483(lgg3\.
\ox
e h \j . . ' a n d l - t o s y l o x y - 2 - a l k a n o l s s n : ;ranohydrin silYl ethers and t l . r . : . l l c o h o l s a r e a c q u i r e da f t e r p: ,j.r.t\ of nitriles and d-hydroxy
Diisopinocampheylborane, (Ipc)2BH, and B derivatives. 13, ll7-l18 chiral 1,4-diols.' Reaction ofallyl ketoneswith this organoboraneproceedsby a rapid hydroboration, which is followed by an intramolecular reduction. An alternativemethod2comprisesenantioselective allylation of aldehydes,which results in cyclic oxaboranes, transboration with BHr . sMez, and then oxidation. Prior to the oxidation the carbon chain can be elongatedby reaction with BrcH2Cl, BuLi. The diols have been converted to optically active 2-alkylpyrrolidines and -piperidines.
^< 3-O
o
"4"
V),'t"r"'z TftF, -1000; BH3. SMe2 ; MeOH
_
?M" O,B\ t l
r"n{)
#)^ (> 98% ee)
Dirrl! borohydride 142 Diisopropoxytitanium(III)
are preThe useful synthetic reagents Functionarized l-atkenyrboronates, of the l-alkynes with (Ipc)zBH and treatment pared by hydroboration of substituted unO tetramethylethyleneglycol'3 alkenylboraneswittr acetald"t'ya" is a reducing agent that furCarbinols. B-Chlo;diis;pinocampheylborane group' carbinols in c-n bond geminal to rhe methyl nishes a hydride by severingttre o-hydroxyacetophetrifluoromethyl ketonesa'sand good ee are formed r.orri tr,. nones.olnterestingly,theconfigurationofthelatterseriesisoppositetothatofthe reduction products of o-methoxyacetophenones' 3-Heteroallylboranes.l.8The3-amino-and3.silylallylderivativesarevefy v a l u a b l e r e a g e n t s r o , t n e ' y n t t , e s i s o f a r r t i - 3 . a m j n o . l - a l k e nlatter - 4 . o lcases' s a n d aan n t ioxida-|-a|kenewith aldehydes'In the 3,4-diols'respectively,Uy-tonO"n'ation tive desilYlationis required'
Dilithium tetramethylcobaltate. Substitution of alkenyl and alLytyl tluorides with a methyl group in exccll ferrate reagent.
T. Kauffmann,R. Salker.and K.-U \ot'. C
Dimesityl(atkYl)borane. 14' 6 Homologation of alkYl halidcshalide to the homologous alcohol crpl ralkyl)lithium by deprotonationand tlr ' cies.Conventionaloxidationafter tltc all also be used as electroPhiles.
l-Pr2N. 7
2'usi',
BuLi - TMEDA;
.
BF3'OEt2
^J \
"l'"v\,'\ r
,-Pr2N, /
9611Q,-780;
OH I
.*;; *T MeOH
A. Pelter,L. Warren,J.W.Wilson.G F \ 1007( 1993).
OH
,/t
82")"aoM" ' C. A. Molanderand K' L' Bobbitt'JOC 59' 26'16(1994\' (1993)' p. eJi-t"i. s"row'andB' Singaram'TA 4' 189 ,T. Nguyen,D. Sherman, (1993)' 2s5l 23' SC Suzuki' A' and rA. Kamabuchi, T' Moriya'Nl rtaiyuutu' T 49' 1725(1993)' 'P.V. Ramachandran' A'V' f"oaolouit' undH'C' Brown' (1994)' Brown'rA 5' 106l' 1075 c i"ooo'ouic' sp.v. Ramachandran' B G";;';'u' T-d-Y (1994)' 2141 6P.V.Ramachandran' B coni' unoH C' Brown'TL35' ' e . C . V . B a r r e tat n dM ' A J e e f e l dI '4 9 ' 7 8 5 ?( 1 9 9 3 f - ; . ; . M . B a r r e tat n dJ ' W 'M a l e c h aJ' C S ( P l l)9 0 l ( 1 9 9 4 ) '
Di methylaluminyl phenyl sulfidc. 2-Alkyt-2-cyclohexenoncs.' Thc r by conjugateaddition and trapping of th eration of the double bond and remorll rnesylation.Actually, the liberatedthtd ,:ess;thus the final operation involres d
O -78o; Me2AlSPh,CH2C12, RCHO.THF,.78O
DiisoProPenYl oxalate' O x a l y l a t i o n . ' s e l e c t i v e r e a c t i o n w i t h n u c l e o p h i l e s i s a c ctwo o mdifferent plishable 'Forexamines' with formed in a stepwiseprocess are oxamides mixed ample, (1993)' 'M. Neveux,C. Bruneau'S' Lecolier'andP' H' Dixneuf'T 49'2629
borohydride'. Diisopropoxytitanium(III) (i-PrO)zTiClz and agent is prepared in situ from reducing 1,2'Reduction'' This cara,B-unsaturated of in the- reduction (phNEtrBH4. It sfrows fhemo.eleJtiuity bonyl comPounds' rK.S.Ravikumar,s.Baskaran,andS.chandrasekaran'JOC58'5981(1993)'
Ot{
. \ " t l vsn 36€5\
M . A . A r m i t a g e , D . C . L a t h b u r Y ,a n d M I
Dimethylamino(dimethyl)[o'hydror Alcoholprotection'' An alcohol (70-95%).Su :on at roomtemperature 'ore,the deprotection avoidsthe addrt
Dim€thylamino(dimethyl)[o-hydroxy.(E)-styryl]silane143
are Pre[u -r nthetic reagents of the ,L 13-rlBH and treatment h..::: glvcol.l fur:. ., reducing agent that in h : i lnethylgroup' Carbinols tc-.-'' and o-hydroxyacetoPhethat of the r ..":.- r\ oppositeto very i--: riall.,-l derivativesare . . .. xcn-'l-ols and 4t'tti-l-alkenecases'an oxidatdt. ln the latter
Dilithium tetramethylcobaltate. Substitution o! alkenyl and alkynyl halides.l Replacementof the chlorides and fluorides with a methyl group in excellentyields is achieved with the cobaltate or ferrate reagent. rT. Kauffmann,R. Salker,and K.-U. Vob,CB 126, 144'7 (1993).
Dimesityl(alkyl)borane. 14, 6 Homologation of alkyl halides.t A new way for the conversion of an alkyl halide to the homologous alcohol exploits the facile formation of dimesitylboryl(alkyl)lithium by deprotonationand the excellentnucleophilicityof the lithiated species.Conventionaloxidationafter the alkylation completesthe process.Epoxidescan also be used as electrophiles.
OH
"699, -780;
\ :
KF'H2O2 MeOH
-\^
,A. pelter,L. Warren,J.W.Wilson.C. F. Vaughan-Williams, and R. M. Rosser,T 49,2988, ( 3007 r993).
OH
rl
(1993)' rt,ii-r:1. fA 4, 189 :r . l-1 l85l (1993). ' {9. t1:5 (1993)' r(1994)' B"'*n. IA 5, 106l' 1075 H : l 9 9 r l ) . $ -
Dimethylaluminyl phenyl sulfide. 2-Alkyl-2-cyclohexenones.' The alkylation of2-cyclohexenonecan be initiated by conjugateadditionand trappingofthe aluminum enolatewith an aldehyde.Regeneration of the double bond and removal of the hydroxyl group are accomplished by mesylation.Actually, the liberatedthiolate displacesthe allylic mesylatein the process;thus the final operationinvolvesdesulfurizationwith Raney nickel.
I F:
O Ma2AlSPh, CH2C|2, -78o;
RCHO, THF, -78O
For exlc..::.:ler is accomplishable' a mines' d i f f e r e n t r r' 'c.r with two r-'
A
f
O
T
\.Aspn
" H
H O S P Meso2ct.NEt3,cH2ct2oo; a\^* -sio2,cH2cl2,rt
I
\,'/
ll
o
h
ErOH,250
r'f* t r l
51-64"/.
I 4 9 .2 6 2 9( 1 9 9 3 ) ' M. A. Armitage, D. C. Lathbury, and M. B. Mitchell' JCS(Pl) l55l (1994).
(i-PrO)zTiClzand rir:iJ rn situ from cara,B-unsaturated of r ::Jucrion
r : z - . t t ) C5 E ,5 9 8 1( 1 9 9 3 ) '
Dimethylamino(dimethyl)[o-hydroxy-(E)-styryUsilane. the dimethylaminogroupfrom siliAlcoholprotection.t An alcoholdisplaces' (70-957o).Suchsilyl ethersarephotolabile(254nm); thereron at roomtemperature 'bre,the deprotection avoidsthe additionof reagents.
144 DimethYldioxlrane
Y
""r"')tftz--p FOH
*
o-o
rN (254 nm)
THF
ROH
HO'
MoPO-C f
83-920/"
' M. C. PirrungandY. R. Lee,JOC5E' 6961(1993)'
DimethYl carbonate. of ketones may be followed by Ketonc-cster exchange't Carbomethoxylation deacylationinsituwhenthereactioniscarriedoutathightemperatures. Methy|ationofactivatedtoluenes,2Ary|acetonitrilesandmethylarylacetates aremonomethylatedatthebenzylicpositiononheatingwith(Meo)zCoandKzCo: in an autoclaveat l80oC' 3.Methyloxazolin.2.ones.lUndersimilarconditionsketoximesundergothe yield' very unusual heterocyclization in 22-48Vo (MeO)2C=O NOH
K2CO3,1900
,'^t-.-O.
I
ilFo
\-,,^N
487o
'M. Selva,C. A. Marques,andP' Tundo'G 123'515(1993)' tM. Selva,C. A. Marques,andP' Tundo'JCS(PI)t323(1994)' (1993)' tC. A. Marques,M. Selva'P' Tundo'andF' Montanati'JOC 58' 5765 14' 148; 15' 143-144; 16' 142-144 Dimethyldioxirane. 12, 413; 13' t20; in situ'l Generatedfrom Caro's acid and used prone to of allenic products Epoxidation. The epoxidation ::iP:l"l^.:re isoinduce group in proper distance may secondary reactions; tnus an aldehyde merization.2
!c:, ' o""\
X KzCOs/ MeOH
o
r
ll
),^)
o.-r< ,
OMe 837"
oxidations.Secondaryalcoholsareselectivelyoxidizedtoketones,including are C2-slmmetricl"anage;'''o sec;sec-l'Z-Drols'which vic-diols (without C-C ;; purity'l cal, give chiral ketols in high optical
!t
Sulfides are oxidized to sulfoxides.^( 'noval of a benzylthioethylgroup? from 1 nakes the group base-labile.When thc s rears chiral ligands, the oxidation beconx Cyclic thioamidesare desulfurizedto i Ketoximes,rohydrae C:N - C:O. rr)nyl products.
Hydroxylations. Titanium enolatest on exposurt :urnish a-ketols (60-97%o)ta ( 7 8 ' C , m i n ) . I :.rpid De-O-benzylation.ts The oxidatirc 'rher functional groups,including second Oxidation of aromatic and hctctol Tethoxyarenesto afford p-quinones'u rcg Benzofurans and substituted indoles u '.rngereadily to give benzannulatedlactoo ' ' malealdehyde,rewhich can be trapped I
e)
\1 o-o M€2CO
/-r
or-rc (
00,0.5h
(- W. Jones, J. P. Sankey, W. R. Sandcrsor l994). l K. Crandall and E. Rambo, IL 35' l'tt9 t R C u r c i , L . D ' A c c o l t i , A . D e t o m a s o ,C . F u r \'ry. TL 34,4559 (1993). P B o v i c e l l i , P . L u p a t t e l l i , A . S a n e t t i .a n d E L - D ' A c c o l t i , A . D e t o m a s o ,C . F u s c o . A . R t R S . G l a s sa n d Y . L i u , Z L 3 5 , 3 8 8 7 ( 1 9 9 { t T - H . C h a n a n d C . - P .F e i , C C 8 2 5 ( 1 9 9 3 ) * i t, \ t
A . S c h e n k ,J . F r i s c h , W . A d a m , a n d F P C l a u d i a , E . M i n c i o n e , R . S a l a d i n o .a n d I A. Olah, Q. Liao, C.-S. Lee, G. K. S- Pn A l t a m u r a ,R . C u r c i , a n d J . O . E d w a r d s . Saba. SC 24' 695 (1994)-
Dinethyldioxirane 145
X
o*o
F--(254 nm)
ROH
Me2CO- CH2Cl2
MsCN
00.8h
83-92"/o
>960/o (g4o/oeel
Sulfides are oxidized to sulfoxides.nOne applicationof this reaction is the reThe oxidation moval of a benzylthioethylgroupT from protected oligosaccharides. makes the group base-labile.When the sulfide is coordinatedto a metal that also
'retones may be followed bY )f hrshtemPeratures. afld methyl arYlacetates 11111j3r (MeO)zCOand KzCOr *tth 11;
bearschiral ligands,the oxidationbecomesenantioselective.s Cyclic thioamidesare desulfurizedto afford imines.o give carC:N - C:O. Ketoximes,r0hydrazones,rrand diazo compounds1213 bonyl products.
611;,,n.ketoximes undergo the
Hydroxylations. Titanium enolatesundergo diastereoselectivehydroxylation to furnish a-ketols (60-97vo)taon exposureto dimethyldioxirane.The reactionis very r a p i d( - 7 8 " C , l m i n ) .
\ - c Ve
€',
De-O-benzylation.t5 The oxidative cleavage occurs without affecting many other functional groups,including secondaryalcohol, OTBS. Oxidation of aromatic and heteroaromatic cornpounds. The oxidation of methoxyarenes to afford p-quinones'orequiresacid catalysts. Benzofurans and substituted indoles undergo epoxidation, but the products rearrangereadily to give benzannulatedlactonesrT Furan itself is converted and lactams.rE ro malealdehyde,re which can be trappedby Wittig reagents.
9!.3
o ( t t s 7 6 5( 1 9 9 3 ) .
lJl
lJ-l: 16' 142-144
llc:.:; comPoundsare Prone to r r l . r J l s t a n c em a y i n d u c e i s o -
o
: k ' .
OMe
83'. l r .,rrdized to ketones, including Drols, which are C2-slmmetri-
a
X
o-o MezCO 00,0.5h
Ph3P=CHCHO
H
C
cHO
cq2clz
J.:\
OHi
\:J
-CHO
62%
C . W . J o n e s , J . P . S a n k e y , W . R . S a n d e r s o n ,M . C . R o c c a , a n d S . L . W i l s o n , J C R ( S ) l l 4 (t994). rJ. K . C r a n d a l l a n d E . R a m b o , T L 3 5 , 1 4 8 9( 1 9 9 4 ) . 'R. C u r c i , L . D ' A c c o l t i , A . D e t o m a s o ,C . F u s c o , K . T a k e u c h i ,Y . O h g a , P . E . E a t o n , a n d Y . C . Yip, rL 34, 4559 (t993). 'P. B o v i c e l l i , P . L u p a t t e l l i , A . S a n e t t i , a n d E . M i n c i o n e , T L 3 5 , 8 4 7 ' 1( 1 9 9 4 ) . 'L. D ' A c c o l t i , A . D e t o m a s o ,C . F u s c o , A . R o s a , a n d R . C u r c i , J O C 5 8 , 3 6 0 0 ( 1 9 9 3 ) . -R.S. G f a s sa n d Y . L i u , r L 3 5 , 3 8 8 7 ( 1 9 9 4 ) . -T.-H. C h a n a n d C . - P .F e i , C C 8 2 5 ( 1 9 9 3 ) . 'W. A . S c h e n k ,J . F r i s c h , W . A d a m , a n d F . P r e c h t l , A C I E E 3 3 , 1 6 0 9 ( 1 9 9 4 ) . 'C. C l a u d i a , E . M i n c i o n e , R . S a l a d i n o ,a n d R . N i c o l e t t i , T 5 0 , 3 2 5 9 ( 1 9 9 4 ) . G . A . O l a h , Q . L i a o , C . - S . L e e , G . K . S . P r a k a s h ,S L 4 2 7 ( 1 9 9 3 ) . A . A l t a m u r a , R . C u r c i , a n d J . O . E d w a r d s ,J O C 5 8 , 7 2 8 9 ( 1 9 9 3 ) . 'A. S a b a ,S C 2 4 , 6 9 5 ( t 9 9 4 \ .
145 1,3-Dimethylirnidazoliumiodide lrP. (1993)' D a r k i n s , N . l v l c C a r t h y ,M . A . M c K e r v e y , a n d T ' Y e ' C C 1 2 2 2 'oW. A d a m , M . M i i l l e r , a n d F . P r e c h t l ,J O C 5 9 ' 2 3 5 8 ( 1 9 9 4 ) . IsR. Csuk andP. Ddrr, I50,9983 (1994). 'ow. Adam and M. Shimizu' S 560 (1994). ' t w . A d a m a n d M . S a u t e r ,7 5 0 ' l l 4 4 l ( 1 9 9 4 ) . t'2. Z h a n g a n d C . S . F o o t e , , / A C Sf 1 5 ' 8 8 6 7 ( 1 9 9 3 ) . ''B.J. Adter, C. Barrett, J. Brennan' P. McGuigan, M'A' McKervey' and B' Tarbit' CC 1220
MeNA
NPh ll ArAct
,' lsrm
+ A''CHO
NaH / T}f
A . M i y a s h i t a , H . M a t s u d a ,a n d T . H i g a s h r m .
( 1993).
N,N-Dimethylformamide-phosphoryl chloride' of o-hydroxyalkylCyclodehydration.t A mild and efficientcyclodehydration to largeis adaptable method The Cl-. phenolscalls for the useof clcH:N*Mez scaleoperations. OH l ^
n
pnnoloA&o.vovPh
(Y' \.Aox
H ofo^o^en
Dimethyl methylphosphonate. 16, 145 Cycloalkenones. The nucleophilic a disubstituted 1,3-cycloalkanedionesnas Wadsworth reaction to give 3-substituted l The reaction of the same reagent ritl phonates),which may undergocyclization rapid aldolization, permitting subsequcnlr I -cyclohexenones.
Cl' [CICH=NMe2]+ EtsN
o
9]---o'--o--en LiCH2PO(OM6)2 78"/o
,\
t i l I
rP.A. Procopiou, A.C. Brodie,M.J. Deal,andD'F' Hayman'TL34''7483(1993)' N, N-Dimethylformamide -th ionyl chloride' sulfene.t Methanesulfonic acid gives sulfene (CHt:59r;
on reaction with the
Vilsmeier reagent. 'D. Prajapati, S 468 (1993)' S.P. Singh'A. R. Mahajan,andJ' S Sandhu,
2,2-Dimethylhydrazino(di methyl)aluminum. and Hydrazones.t The reagent is prepared from N,N-dimethylhydrazine of unretrimethylaluminum in hot toluene (977o yield).It is useful for derivatization substituted active ketones (e.g., ferrocenyl ketones) in refluxing toluene. The fully hydraTropone hydrazonescan undergo exchangeon reaction with NzH+ in ethanol. method' this by zone, which has previously been unavailable, can be prepared ' B . B i l s t e i na n dP . D e n i f l ,S 1 5 8( 1 9 9 4 ) .
1,3-Dimethylimidazolium iodide. presence a-Diketones.t N-Phenylimidoyl chlorides react with aldehydesin the resultofthe ofthe imidazolium iodide and a base (ylide generation).Acid hydrolysis ing o-keto imines leads to a-diketones'
2H3%
/.COOMa :r.COOMe
LicHzpo(oMe)z-
I g po( | .-u.
luq" I
L
T . F u r u t a . E . O s h i m a . a n d Y . Y a m a m o t o .t C :E. W e n k e r t a n d M . K . S c h o r p ,J O C 5 9 , 1 9 4 3| V. Mikolajczyk and M. Mikina, JOC 59.6ft
Di methyl(methylthio)sulfon ium srlts. The triflate is effe< Glycosylation' rllylcarbamoyl group for reaction with gl1
Disulfidc bond formation.z Couplir achievedon treatment with the tetrafluom
H. KunzandJ. Zimmer,TL34,2907 (199\t 'P. Bishop,C. Jones,andJ. Chmielewski, fL I
Dimethyl(methylthio)sulfoniumsalts 147
-:t ,1993).
It g
NPh ll ArAcl
\1,i':'rr€\. and B. Tarbit' CC 1220
krJ: nr tl ration of o-hydroxyalkylhc rrc'rhod is adaPtableto large-
'
+ AI'CHO
MeNa i NMe r - v
NPh ll
nr.\rZAr NaH / THF
O I
,n,
l:
l
l
o
l
nr.\.,A/ l
o
A . M i y a s h i t a , H . M a t s u d a ,a n d T . H i g a s h i n o , C P B 4 0 , 2 6 2 7 ( 1 9 9 2 ) .
Dimethyl rnethylphosphonate. 16, 145 Cycloalkenones. The nucleophilic attack of lithiomethylphosphonateson 2,2' disubstituted 1,3-cycloalkanedionesresults in fragmentation and EmmonsWadsworth reaction to give 3-substituted 2-cycloalkenones.' The reaction of the same reagent with a,99: l)
':lz EU
Fluorine.13, 135; 14, 167; 15' 16 Ele ct roPhilic f luorination'' rn 9870formic acid or sulfuric aci The yield for direct fluorination c
\ , t Ert
PO'b ( tl
o tl
: po
Y"
\g.
\--H'H
irom l57o to 90Vo. Fluorination of allencs'' t oresenceor absenceof dry NaF' and it must be carried out at lo$
I
I
i anti
syn
peraturesto avoid charring'
rK. Mikami,M. Terada' andT' Nakai'CC343(1993)' Europium tris[trif luoromethyl(hydroxymethylene)-d-camphorate' catalystfor cycloadditioninDiels-Alder reaction.t Eu(hfc), is an efficient a-pyronesystems' volvingelectron-deficient o COOMe
)'v" (.6
t
CH2Cl2
tr\
rt.6h 88%
rI.
R . D . C h a m b e r s 'C ' J ' S k i n n e r . J T R . D . C h a m b e r s ,M ' P . G r e e n h a l l ' t T. Arimura, M. Shibakami,M Trt
I l-cool,l"
(o" rr
HzC=C=Cl{Oll
(1994)' E . M a r k o a n d G . R . E v a n s ,S L 4 3 1
oEt
)i V-Fluorobis(benzenesulfonY Fluorination of aromotkl derivedfro .]romto arYllithiums
\'. Snieckus, F. Beaulieu, K Mottt , 1994).
r2- Fluoro-4' -carboxY)triPbc!! Peptide sYnthesis.t The re
rn acid-labile handle. A Fmoc :hereafter the Fmoc grouP ls I * ithout affecting the ester linh
C. C. Zikos and N' G. Ferderigos
a {.(.mPhorele 3 S \te1 . amtrr
c€: nti >99:1) 7 5 " 6( s 4 na
Fluorine. 13, 135; 14, 167;15, 160 Fluorination of aromatic compounds is effective Electrophilic fluorination.r with a l:9 mixture of F2-N2at room temperature. acid sulfuric acid or in 987oformic of 1,3-dicarbonylcompounds2by this system varies fluorination The yield for direct
:, _ I
from l5Vo to 90Vo. Fluorination of allenes.3 Allene behaves differently toward fluorine in the presenceor absenceof dry NaF. The reaction of various allenes is explosion-prone and it must be carried out at low temperature. Cyanoallene requires even lower temperaturesto avoid charring.
) 9'r
F2- NaF
!th r lene)-d'camPhorate' c:: :. renl catalyst for cycloaddition
o // 9 l-coottle
:c, t'
zl-\
^)
oEt 88'/"
H2C=C=CHoMe
F3ccF2cF2ocF3 -.,*lo" 89o/"
'R. D . C h a m b e r s .C . J . S k i n n e r , J . T h o m s o n , a n d J . H u t c h i n s o n ' C C 1 7 ( 1 9 9 5 ) ' :R. D . C h a m b e r s ,M . P . G r e e n h a l l , a n d J . H u t c h i n s o n ' C C 2 l ( 1 9 9 5 ) . 'T. A r i m u r a , M . S h i b a k a m i , M . T a m u r a , S . K u r o s a w a ,a n d A . S e k i y a , . / C R ( S )8 9 ' ( 1 9 9 4 ) '
.V-Fluorobis(benzenesulfonyl)imide. Fluorination of aromatics.' (Phsor)rNF is useful for deliveringa fluorine atomto aryllithiumsderivedfrom directedortho-metallation' 'V. Snieckus, K. Mohri, W. Han, C. K. Murphy,and F' A' Davies,TL 35' 3465 F. Beaulieu, (1994). bromide. (2-Fluoro-4'-carboxy)triphenylmethyl Peptide synthesis.t The reagent(1) is useful for solid-phasepeptide synthesisas an acid-labile handle. A Fmoc amino acid may be derivatized as the trityl ester, rhereafter the Fmoc group is removable by treatment with 40Vo piperidine-DMF without affecting the esterlinkage.
cooH
x=F,cl (1) C. C. Zikos and N. G. Ferderigos, TL 35, 1767 (1994)
162 N-Fluoro'2,4,6'trimethylpyridinium
triflate
Fluoroboric acid. cyclic ethers are converted to Allylic rearrange'nent't 2-Alkenyl-2-alkylthio enol ethers at low temperature' - .9 r , -- -:^..^ tricarthe presence of 4'l' molecular sieves' Electrophilic substitutions' In trapped with from the appropriatedienols2can be bonyl(dienyl)iron catronsgenerated The molecusieves. the cavities of the molecular an alcohol thar is too bd;; ;; enter MgSOa is role in regiocontrol' When anhydrous lar sieves also play an important internal allylic position' used, some reaction occurs at the Enolsilylethersundergoalkylationwithdicobalt-complexedpropargylicalcoh o l s a f t e r i o n i z a t i o n o r t t r - e t a t t e r w i t h f l u o r o b o r i c a c i d . 3 A l , l , l ' 3 , 3 , 3of . h eax aweakly fluorocobalt exerts its effect by virtue isopropylphosphite Iigand on the and strongly a'-acceptingbehavior' o-ao*iig 'J. P. Hagen,JoC sE,506(1993)' t6. qulr"o,u-Cuillouand J'-P' Lellouche'JoC 59' 4693(1994)' JAcs ll5' 6438(1993)' '1. ift'r. Caffyn andK' M' Nicholas'
N-Fluoro'2,10' (3,3-dichlorocamphorsultam)' Fluorinationol"otot"''Asymmetricfluorinationisobservedinmoderate reagent(1)' yields and enantiomer excesseswith ^l
rtl-"' t-rl VN_F
-;F--^ o (1)
at room temperature. The reagent serlc electron transfer Process. rtl Dimeric alkenes from stabilizcd t singlc a by water, the reaction proceeds two loses cal dimerizes,and the dimer andV' V 9 A. S. Kiselyov,L. Strekowski, ' A. S. Kiselyov,TL 35,8951(1994)'
Fluorosilicic acid. 17' 139 Selective deprotection of trialtyls when a r-butyldimethylsill retained be at room temperature' acid rosilicic
/OSiMe?8u'
,r"S,/V
{ . S . P i l c h e r a n d P . D e S h o n g ,J O C 5 t ' 5 l
Formic acid. 13' 137 Deprotection of AdPoc-amino .nethylethoxycarbonyl group from th ;rently cleaved by treatment with forn Reductive ilechlorination of cUa :ron proceedsunder mild conditions l
I F. A. Davis,P. Zhou,and C' K' Murphy' TL 34' 39'71(1993)'
Semihydrogenation of alkYncs'' Pd(0)-catalyzedtransfer reduction of .electivityof 89-987o. The reducingI
N-Fluoropyridinium salts' 16' 170-17l Functionalizationofpyridine.Regioselectivereactionwithoxygen,sulfur,and C-2 occurs via an additionunO *ltf' carbon nucleophiles2at "ir."g"" "".f"ophil,''
Reduction of carbonYl comPoutJ i-deazaflavins.aFormic acid recycks a-HydroxY acids are obtained' in -.rtalyzed cleavageof diallyl oxosrrc rrxylation, and reduction of the keto
elimination Pathway' JI]C fo' tl6t (l??1)' rA. S. KiselyovandL. Strekowski, t n. i. fir"fyou and L' Strekowski'"IOC58' 4476(1993)' trif late' N-Fluoro'2,4,6'trimethylpyridinium to of carbonyl compoundsin moderate Generation Hyttrolysisof ditnio'ac)ian't medium aqueous and organic (e.g., cH2cl) good yields is accomplished in a mixed
o i
,nt-tAo* t ^4;-t-..\ " t l o
l
^
h
E
Formicacid 163
o -r.llc ethers are convertedto .,' : i molecular sieves,tricarrrr:. jrenolsr can be traPPedwith lr ::.,'lecularsieves.The molecuj1,, \\'hen anhYdrousMgSOa is
at room temperature. The reagent serves as an electron acceptor to initiate a single electron transfer process. Dimeric alkenes from stahiliZed Wittig reagents.2 In the presence of traces of water, the reaction proceedsby a single electron transfer mechanism. The cation radical dimerizes,and the dimer losestwo phosphinemolecules' 'A. S. Kiselyov,L. Strekowski,and V. V. Semenov,T 49' 2l5l (1993). rA. S. Kiselyov,TL 35,8951(1994).
t\ll:,'n.
rail'.,'mplexedpropargylicalco: .r,:.i A I,1,1,3,3,3-hexafluoros .::ect bY virtue of a weaklY
Fluorosilicic acid. 17, 139 ethers.' A triisopropylsiloxy group can Selective deprotection of trialkflsilyl be retained when a t-butyldimethylsilyl group is removed on treatment with fluorosilicic acid at room temperature.
/:\
l q e :
/r
9!:
,-P13SiO
,OSiMezBur
(1x) HzSiFe t-BUOH rt
A/Y
oH
,-Pr3SiO
ri:ilr(rn is observedin moderate '
l.-i
r. :jr!tton with oxygen'sulfur, and lc. :t C-l occursvia an addition-
l !
A . S . P i l c h e r a n d P . D e S h o n g ,J o C 5 E , 5 1 3 0 ( 1 9 9 3 ) .
Formic acid. 13. 137 Deprotection of Adpoc-amino acids and peptides.' The l-adamantyl-lmethylethoxycarbonyl group from the N-protected amino acid or peptide is efficiently cleaved by treatment with formic acid in trifluoroethanol and chloroform. Reductive dechlorination of chloroarenes.2 Catalyzed by Pd-C the dechlorinarion proceedsunder mild conditions.PCBs are destroyedby this method' Semihydrogenation of alkynes.l Formic acid is a hydrogen source for the Pd(0)-catalyzedtransfer reduction of the triple bond to afford the (Z)-alkene with a selectivityof 89-98Vo.The reducingsystemalso contains triethylamine' Reduction of carbonyl cotfrpounds. The reduction is effected with 1,5-dihydroFormic acid recyclesthe spentreagent. 5-deazaflavins.o a-Hydroxy acids are obtained, in the presenceof triethylamine,by rutheniumcatalyzed cleavageof diallyl oxosuccinates.sPresumably via ester cleavage,decarboxylation, and reduction of the ketone.
o i
pn/'Yo/'-< ^4.rzo.-.\ " t l cr:h"n) I comPoundsin moderateto c i CH:Cl:) and aqueousmedium
l
-
[(cod)Ru(OCOCF3)2]2 HCO2H
OH
I
PhMCOzH El3N,DPPB,dioxane 1000,4 h
80%
164
Formic acid
Hydrationofterminalalkynes'6Inanhydrousmedia,formicacidactsasan is necessaryfor the "quiuul"nt of water in the conversion.Activation with Rur(co)12 to the treatment' inert reaction of functionalized alkynes, which are otherwise Ru3(Co)12 HcooH
.. \
\r^v oH
r00o
o tl ""Zt'..' I
o-""o
Gadolinium(III) isoProPoxidc. Redox reactions.t In the Pn tively, oxidation of alcohols and re
85"/"
rsopropoxideat room temPeratur€
t h
' W . V o e l t e r a n d H . K a l b a c h e r ,l , A l 3 l ( 1 9 9 3 ) . (1993)' tJ. P . B a r r e n , S . S . B a g h e l ,a n d P . J ' M c C l o s k e y ' S C 2 3 ' 1 6 0 l rK. Tani, N. Ono, S. Okamoto, and F. Sato' CC 386 (1993)' a 541 (1993)' K. Kuroda, T. Nagamatsu, R. Yanada, and F' Yoneda' JCS(PI) tY. I ' S h i m i z u' and A' Yamamoto' JOMC T ' S a k a m o t o ' T e k a w a , M . Maruyama, T Sezaki, 473.257 (994). oN. Menashe and Y. Shvo, JOC 58,'7434 (1993)'
M. Kinosh T. Okano,M. Matsuoka,
Gallane. Reduction of carbonYl conPo cient reductionwith GaHr NR. r
example, 4-t-butylcyclohexanorr 8 7 : 1 3 .A s g a l l i u m i s m o r e e l e c t rhan alane. However, the two ree giving allylic alcohols.
C. L. Raston,A. F.-H.Siu,C. J. Tnt
Gallium. Allyl- and proPargYlgalliut ;onverted to allylating agents for observedwith silyl-substituted bn
Bi
,/\//\-... * v siMe3
R
r
>O
R'/
;
,r'.HanandY.-2.Huang,IL 35.9{
Gallium(Il) chloride.17,140 Reductive Friedel- Crafts a ce CaCl .GaClr, and advantages Lewisacidityof Ga(III).Thusth nesdirectly affordsalkylarenes
s -'r..1r1.formic acid acts as an 'rt-.,CO)r: is necessarYfor the rh r :.r : nc'rtto the treatment'
isopropoxide. Gadolinium(lll) Redox reactions.t In the presenceof cyclohexanoneand isopropanol, respectively, oxidation of alcohols and reduction of ketones are catalyzedby the lanthanoid isopropoxide at room temperature or below. 'T. Okano,M. Matsuoka, M. Kinoshita,andJ. Kiji, NKK 487(1993)' t
qq-]).
t-.
('.; :17(1993). ' \ ^ ^ : / u . a n dA . Y a m a m o t oIOMC
Gallane. Reduction of carbonyl compounds with Lewis base adducts.' The highly effiFor cient reductionwith GaHl NRr or GaHI PR: also showsdiastereoselectivity' ratio of a trans:cis example, 4-l-butylcyclohexanone furnishes the alcohols with reactive gallane is less 87:13. As gallium is more electronegativethan aluminum, than alane. However, the two reagentsbehave similarly in the reduction of enones, giving allylic alcohols. rC. L. Raston,A. F.-H.Siu,C. J. Tranter,andD. J. Young,IL 35, 5915(1994)'
Gallium. Allyl- and propargylgallium reagents.' Allylic and propargylic bromides are converted to allylating agents for carbonyl compounds. Regioselectivereactions are observedwith silyl-substituted bromides' SjMe3
a,/Vsiu",
+ > o e''
Ga Kt - Lict THF, ^; Hgo*
* ^y/V *5f|l..,"". oH oH > 90% (total yield) (EjZ>90: o * *'."1 90% (96:4)
"*
s' T 49,7239(1993)' E \! P 'ursouli
with glyrzc; reectionof arylacetonitriles arylinto transformed readily u:.:'h are 1,.
Addition to imines. In the presenceof LiCIO+, r'r-bromonitrilesare attacked by Grignard reagentsto form cyclic imines in a tandem addition-cyclizationreaction.T lmines themselvesare activatedby l-(trimethylsilyl)benzotriazolein the Grignard :eacrion.8 Chiral N-(alkylthio)iminesgive optically activehomoallylic amine deriva:rveson reactionwith allylmagnesiumbromide.' The presence of additives can change the diastereoselectivity of Grignard -:actions.lo
16E Grignard reag€nts
Some trif luoromethyl compounds suc \ to alkenes.teTrifluoroacetyl-stabilized trct acid on decompose but the products dependencyof the stereoselectivitlon ti
N.Rn Vo y t t -l'-'n o )---/-o ' c t u g J
w n
l
CFs
\o
n,oo"#o -78o 680/" CeCI3/THF,Et2O, -40o Cul - BF3'OEt2/ El2O,
RLgI
PPh3
derivasalts. N-Alkyl-rr or N-alkoxycarbonyl Adtlition to chiral pyridinium atC-2' attack to asymmetric induction during tives12are equally 'u"tO""O'" d,B-unsaturated Clharge-iirectedaddition to a-silylated Conjugate addition. substrates' is suppressedin such amidate anions is observed'13-l'i-eaOition with Grignard reagents a'B-Epoxy hydrazonesreact Attdition-frag'nent(ttion'
iPrMgCl
CFs NHz
THF -40o-> rl, 3.5 h
/ \
to afford allYlic alcohols''o F'MgBr
^
iAnruHr. /
R
ebo, t1 -
58-71"/"
provides Ring cleavageof a-nitrocycloalkanones
o
o /-,, l l
a synthesis of B-keto silanes'rs
Noz
TMSCH2MgCI THF
fsit',tes
(--r.--.-Noz
-300 -> 00, t h
\
esters are chiral l,l,-biphenyl-2-carboxylate Addition_erimination. Axially reagents'16 Grignard aiyt wittr obtained by the reaction of 2-menthoxybenzoates a of a malonic ester unit constitutes elimination by f"fft*"d Conjugate addition The reagentsare 1,1-dimetalloalkanes' useful method ro, tn. u.."r, io tzl-urt"n"s.17
R ' T " 3oo*
Crignard reagentsto effect chain elong hromineand protodesilyation,it const
MeaSi,
a5"/"
!=a"oo" r
The reaction of (Z)-l-halo-l-alkcnl kctoo halidesresultsin B;y-unsaturated Displacement reactions' I '3- Drbr .rllyltrimethylsilaneby reaction \rith
a'rus.nl.r\ Lne,
2,2_Difluoro enol silyl ethers are 18 methyl triPhenYlsilYlketone'
rHF'
p
R , R "
\1.-i
-78o->-2oo
76-91%
of trifluoroformed by the Grignard reaction
I
Me3Si. NBs
,.oir,
Br
L&
A method for the enantioselectl\c :hrough ring oPening of formYl-Pru O rignard reagents.2,2-Dimethyl-l'3-d 'Aith .cctivering opening on reaction high more the on group :rrn a /-butoxy
.ire formed25when 2-aryl-1,3-dithiole Grignard reagents are thiophilic t with retention of configurati -.rsides26 a-Chloro-a-tolylsulfinylal kanoic c
ir\placing the sulfinYl grouP'2t A benzotriazol-l-yl group attactF( :.i1. Its displacementby Grignard rc1
Grignardreagents 169
Br
Some trifluoromethyl compoundssuch as 2-trifluoromethylanilineare converted to alkenes.reTrifluoroacetyl-stabilizedWittig reagentsundergoGrignard reactions, but the products decompose on acid treatment to give alkenes.20Noteworthy is the dependencyof the stereoselectivityon the acid strength.
: e h
c 9Fo
euoocr.,-\,-,, i l -
DE'' 707o
tsuoocf
RMgX
?"p
H
PPhs
workup: 5% HCI E- selective HOAc Z- selective
,lir - or N-alkoxycarbonYlderival u . : : ' n d u r i n g a t t a c ka t C - 2 ' it:,,-. lr, a-silylated a,B-unsaturat€d pp:l..ed in such substrates' rrl ,nc'\reactwith Grignard reagents
CFa
iPrMgCl
NHC -
THF -40o-> rt,3.5 h
|
^-r
l, a.'-?"" | I|
L**j
Y
r.s',/-1.-
\rl"*l 68/"
io.,
//_8,
58-7'tok
.r nthesisof B-keto silanes.15 l
with allylmagnesium The reaction of (Z)-l-halo-l-alkenyl-1,3,2-dioxaborolanes ketones.2l halidesresultsin Bry-unsaturated Displacement reactions. 1,3-Dibromo-l-trimethylsilylpropene is availablefrom atlyltrimethylsilaneby reaction with NBS. The dibromo compound couples with Grignard reagentsto effect chain elongation.With further displacementof the vinylic bromine and protodesilyation,it constitutesan intriguing approachto (Z)-alkenes.12
..-.SiMes -.----r-..
Measi
NO,
\
85%
esters are .l -r:phen-vl-2-carboxylate gs. .rrth aryl Grignard reagents''u r , t : malonic ester unit constitutesa Ihe :.'agentsare 1,1-dimetalloalkanes'
**,,
",{r-
RMox
Me3si\
-=-
,'FL,
J
\-R
A method for the enantioselectivesynthesisof a-amino acetals(aldehydes)"is through ring opening of formyl-protected,chiral 2-formyl-1,3-oxazolidineswith and dioxanesare subjectto regioseGrignard reagents.2,2-Dimethyl-1,3-dioxolanes The productsconlectivering opening on reactionwith methylmagnesiumiodide.2a rain a t-butoxy group on the more highly substitutedcarbon atom. Styrene derivatives are similarly treated. are formed25when 2-aryl- 1,3-dithiolane-S-oxides Grignard reagentsare thiophilic towards sugar thiocyanates,forming thiogly-
76-91"/o
[.r :rr Grignard reactionof trifluoro-
with retentionof configuration. cosides26 a-Chloro-a-tolylsulfinylalkanoicestersreact selectivelywith Grignard reagents, Jisplacingthe sulfinyl group.tt A benzotriazol-l-yl group attachedto an activatedbenzylic position is nucleofugal. Its displacementby Grignard reagents28 has been demonstrated.
170 Grignardreagents Symmetrical a-diketones can be synthesizedfrom 1,4-dimethylpiperazine-2,3dione2eor 1,1'-oxalyldiimidazole.30 In a general approach to phosphonodithioic acid derivatives,I the first step is the Grignard reaction of P-chloro- 1,3,2-dithiaphospholane. Displacement-rearrangement.32 The reaction of allenesulfinate esters with alkenyl Grignard reagentsproceedsby displacementon sulfur. [2,3]Sigmatropicrearrangementand dimerization follow.
an", "{:-*" IV""]Sp2' displacement. a,B-Disubstitutedacrylic estersand nitriles are available which acidderivatives, of 3-acetoxy-2-methylenealkanoic from allylic displacement3r arereadilyobtainedfrom a Baylis-Hillmanreaction. OAc I *\.cooMe
ll
Allylic
R'MoX
A
Grignard reagents/cerium(III) cl Cerium(III)chloridepolarizes sr lectivitiesin Grignardreactions.I enonesr andnitroethylarenes,2 rcsp
nA:,,'coor'te
rHF
"T. Hattori, N. Koike, and S. Miyano. '' C. E. Tucker and p. Knochel, S 5-10r I ''F. J i n , Y . X u , a n d W . H u a n g ,J C S : p t l ''M. H o 1 . | a tA, . S . K i s e l y o v , a n d L . S r r e t"Y. Shen and S. Gao, JOC 5E,4564 { lt t' H . C . B r o w n a n d R . S o u n d a r a r a j a nI. ::R. A n g e l l , P . J . P a r s o n s ,a n d A . N a l h -'K. R. MuralidharanM , . K. Mokhalle t'w.-L. Cheng,S.-M. Yeh, and T.-y. Lr tt W.-L. Cheng and T.-Y. Luh, HC 3. JO toZ. P a k u l s k i , D . P i e r o z y n s k i ,a n d A . i :'T. S a t o h ,Y . K i t o h , K . - 1 . O n d a , K . T e t'A. R. Katritzky, H. Lang, and X. Ler 3U.T. Mueller-Westerhoff and M. Zhol ''R. H. Mitchell and V. S. Iyer, Il 3zl. J '' S . F . M a r t i n , A . S . W a g m a n ,G . G . Z t 1 ':J.-B. B a u d i n ,M . - G . C o m m e n i l .S . A 'rD. B a s a v a i a h ,P . K . S . S a r m a , a n d A I "A. Y a n a g i s a w aH , . Hibino, N. Nomun '5S. W a t a n a b e ,K . S u g a h a r a ,T . F u j i r e . !
\R'
62 - 75"/"
phosphates are displaced, showing 7-selectivity with respect to allylic
Grignard reagents.ro a-Trifluoromethylacrylic
acid is transformed
acrylic acids35 with various unsaturated Grignard
into
a-substituted
B,B-difluoro-
reagents.
'H.-S. L i n a n d L . A . P a q u e t t e ,S C 2 4 , 2 5 0 3 ( 1 9 9 4 ) . 2T. S a t o h ,Y . K i t o h , K . O n d a , a n d K . Y a m a k a w a , T L S 4 , 2 3 3 1 ( 1 9 9 3 ) . rR.J. B u t l i n , l . D . L i n n e y , D . J . C r i t c h e r ,M . F . M a h o n , K . C . M o l l o y , a n d M . W i l l s , J C S ( P l ) l58l 0993). 4J. A. Marshall and Y. Tang, JOC 58,3233 (1993). 5 M . A . B l a s k o v i c ha n d G . L a j o i e , J A C S 1 1 5 , 5 0 2 1 ( 1 9 9 3 ) . "P. C . B . P a g e ,J . C . P r o d g e r ,a n d D . W e s t w o o d ,T 4 9 , 1 0 3 5 5( 1 9 9 3 ) . tD. F . F r y , C . B . F o w l e r ,a n d R . K . D i e t e r , S L 8 3 6 ( 1 9 9 4 ) . " A. R. Katritzky, Q. Hong, and Z. Yang, JOC 59,1947 (1994\. 'T.-K. Y a n g , R . - Y . C h e n , D . - S . L e e , W . - S . P e n g ,Y . - 2 . J i a n g ,A . - Q . M i , a n d T . - T . l o n g , J O C
s9,9r4(t994).
'oF. L. uan Delft. M. De Kort, G. A. Van der Marel, and J. H. van Boom, TA 5,2261 (1994). " Y . G e n i s s o n ,C . M a r a z a n o , a n d B . C . D a s , J O C 5 8 , 2 0 5 2 ( 1 9 9 3 ) . ''D. L . C o m i n s , S . P . J o s e p h ,a n d R . R . G o e h r i n g , J A C S 1 1 6 , 4 7 1 9 ( 1 9 9 4 ) . rrM. P . C o o k e , J r . a n d C . M . P o l l o c k , J O C 5 E , ' 7 4 7 4( 1 9 9 1 ) . 'o S . C h a n d r a s e k a rM , . T a k h i , a n d J . S . Y a d a v ,T L 3 6 , 3 0 7 ( 1 9 9 5 ) . 'tR. Ballini. G. Bartoli. R. Giovannini, E. Marcantoni,and M. Petrini, IL34,3301 (1993).
O
H-N.Me
,A/--
G. Bartoli, C. Cimarelli, E. Marcanro 'G. Bartoli, M. Bosco,L. Sambri. and I
G rignard reagents/copper salts. Coupling. Dilithium tetrachh bromide with a,ardibromoalkancs have also been used as coupling par
Ss2' displacements. The opcni tions of chlorides are regio- and sren alized allyl thiazolin-2-yl sulfides ir
Grlgnard reagcnts/coppersalts 17l
d :: :r l.'1-dimethylpiperazine-2'3' the first step is the crJ -1.'n\atives,rr - .i '
h'.:
t: - 'f allenesulfinateesters with E - ' r . u l f u r . [ 2 . 3 l S i g m a t r o p irce a r -
rrl:, r'.ters and nitriles are available n c:.celkanoicacid derivatives,which
16T. H a t t o r i , N . K o i k e , a n d S . M i y a n o , J C S ( P I )2 2 7 3 ( 1 9 9 4 ) . 17C. E. Tucker and P. Knochel,S 530 (1993). 'tF. J i n , Y . X u , a n d W . H u a n g ,J C S ( P I )7 9 5 ( 1 9 9 3 ) . ''M. Ho.liat, A. S. Kiselyov, and L. Strekowski, SC 24, 267 (1994). tuY. Shen and S. Gao, JOC 58,4564 (1993). '' H. C. Brown and R. Soundararajan,TL 35,6963 (1994). 22R. A n g e l l , P . J . P a r s o n s ,a n d A . N a y l o r , S L 1 8 9 ( 1 9 9 3 ) . L K. R. Muralidharan,M. K. Mokhallalati, and L' N. Pridgen,TL 35' 7489 (1994). 'ow.-L. Cheng,S.-M. Yeh, and T.-Y. Luh, JOC 58, 5576(1993). "w.-L. Cheng and T.-Y. Luh, HC 3, 505 (1992). 'uZ. P a k u l s k i , D . P i e r o z y n s k i ,a n d A . Z a m o j s k i , f 5 0 , 2 9 7 5 ( 1 9 9 4 ) . "T. S a t o h .Y . K i t o h , K . - L O n d a , K . T a k a n o , a n d K . Y a m a k a w a , 7 5 0 , 4 9 5 7 ( 1 9 9 4 ) ' :8A. R . K a t r i t z k y , H . L a n g , a n d X . L a u , T 4 9 , ' 1 4 4 5( 1 9 9 3 ) . }U.T. Mueller-Westerhoff and M. Zhou, TL 34,571 (1993). r('R. H. Mitchell and V. S. Iyer, TL 34, 3683 (1993). t' S . F . M a r t i n , A . S . W a g m a n ,C . G . Z i p p , a n d M . K ' G r a t c h e v ,J O C 5 9 , 1 9 5 7 ( 1 9 9 4 ) . r?J.-8. B a u d i n , M . - G . C o m m e n i l , S . A . J u l i a , L . T o u p e t ,a n d Y . W a n g ,S Z 8 3 9 ( 1 9 9 3 ) . I D . B a s a v a i a h ,P . K . S . S a r m a , a n d A . K . D . B h a v a n i , C C l 0 9 l ( 1 9 9 4 ) . !A. Y a n a g i s a w aH , . H i b i n o , N . N o m u r a , a n d H . Y a m a m o t o ,J A C S l l 5 ' 5 8 7 9 ( 1 9 9 3 ) . r 5 W a t a n a b e ,K . S u g a h a r a T , . F u j i t a , M . S a k a m o t o ,a n d T . K i t a z u m e ' J F C 6 2 ' 2 0 1 ( 1 9 9 3 ) ' S.
:
l::
'.-,cooMe
Grignard reagents/cerium(III)chloride. to enhancetheir reactivitiesandregioseCerium(III)chloridepolarizessubstrates lectivitiesin Grignard reactions.B-Enaminoketonesand B-nitrostyrenesafford underthe influenceof CeClr. respectively, enonesrand nitroethylarenes,2
'R' ' -
/f-o
1. .: !'.tr\ ity with respect to allylic D.i :,r,, n-substituted B,B-difluorot:.i -.rgenls.
O
CaCl3,THF -780
H.N.Me
*Az\
R.MgX 10% ACOH
65-85%
I
7 ; . 1 { 1 . 1 3(11 9 9 3 ) . rr.. - K C Molloy,andM' Wills' JCS(PI) 'G. Bartoli, C. Cimarelli, E. Marcantoni,G. Palmieri, and M' Petrini, CC715 (1994). r G . B a r t o l i , M . B o s c o ,L . S a m b r i ,a n d E . M a r c a n t o n i , 7 L 3 5 , 8 6 5 1( 1 9 9 4 ) .
::5 r1993).
19 -v:\
/
l.l9{). Jr.rng. A.-Q
Mi, and T -T' Jong' JOC
(1994)' I , - : J H . I a n B o o m ,T A 5 , 2 2 6 1 It I rlr1993). i r , . 1 1 6 . 1 7 1( 91 9 9 4 ) . '.| ,-r' 35 : ,1995). ,n,JM. Petrini,TL 34, 3301(1993)' rr
Grignard reagents/copPer salts. Coupling. Dilithium tetrachlorocupratecan be used to couPle allylmagnesium bromide with o,ardibromoalkanes to provide ar-bromoalkenes.rVinylic tellurides havealso been usedas coupling partners.2 Sp2, displacements. The opening of allylic carbonatesrand displacementreacThe thio unit of functiontions of chlorides are regio- and stereoselectiveprocesses.4 alized allyl thiazolin-2-yl sulfides is selectivelyremoved during the reaction.5
172 Grignard reagents/coppersalts
t H . - J . C r i s t a u ,M . - B . G a s c ,a n d X . Y - Y '8. P i e r s ,B . W . A . Y e u n g , a n d F . F . F l c t
oAo ''.
MsMgBr
I enO,u/-\y?"gZ
Cul - BF3' OEt2 THF, .78O
involves the displacementof A convenient preparation of tributylstannylalkenes6 the synthesis of alkynesT reaction an allylic acetate. By using a bromoallene in the branching at the propargylic position is realized' activating group on nltrogen Opritng of aziridines. Aziridines with an
Grignard reagents/nickel complcr Coupling with neopentyl iodilt Grignard reagentscouple with neog Reaction with enol etherc. 2-S reducedto the (E)-alkenols2with rg nickel chloride complex. The rerr recifeiolide.
undergo electrophilic reactions'8'e Conjugateaddition.Precursorsofunusualaminoacidsareacquiredbytan2-(Oxazolidin-2dem addition and bromination of N-alkenoyloxazolidin-2-ones'r0 compounds' those to route on-3-yl)acrylatesrralso act as acceptorsin an alternative
iPrlgt
/u Ph
.
i-\
RMgX- CUBF SMe2
vYnvo o
THF -780 -> -100 .
6
i"",r.-{iY
P''\-
Displacement of chalcogc nidct C-C bond formation from vinYlic c Conj ugate a d dit ion - eliminat io group of benzamides with ar1.
'\{"n nBuMgX-Cul
Yilvo
BnOOC
O
THF, -780-> 250
THF. .!
6
NBS/THF, -78O
tn
(StrrP)rr€
20h
\1.ntb R c f 89o/. (R=Ph)
";{'
oN
)'YJvo BnOOC
MeOH
o
Pd(oH)2- c THF
93"/o
making disubstituted Alkynylphosphonates undergo stereoselective addition' readily available' alkenylphosphonatesr2 indirectly' for example' from Sometimes vinylic Grignard reagentsare prepared13 The sn/Li exchange is the readily available vinylstannanes via the vinyllithiums. present' be may rapid at low temperature' and a primary chloride 'D. K. Johnson, andJ' Kang,SC 24' 1557(1994)' J. Donohoe, 'A. Chieffi and J.V.Comasseto, TLSS' 4063(1994)' tS.-K. Kang,D.-G.Cho,J.-U.Chung,andD'-Y' Kim' TA 5' 2l (1994)' oJ.-E.Beckvall,E. S.M. Persson, andA' Bombrun'JOC 59' 4126(1994)' tV. Calo, V. Fiandanese, A' Nacci,and A' Scilimati' I50"7283 (1994)' uF.Bellina,A. Carpita,M. De Santis,andR' Rossi'750' 4853(1994)' tF. D'Ani"llo, A. Mann, M. Taddei'and C'-G' Wermuth'TL35"l'l'15 (1994)' ? 49' 6309(1993)' 'J. E. Baldwin,A. C' Spivey,C' J. Schofield, andJ' B' Sweeney' 'H. M. I. Osborn,J. B. Sweeney, 'TL35'2739 (1994)' andW' Howson 'oG.Li, M. A. Jarosinski, andV'J. Hruby'Il 34, 2561(1993)' I'P. A. LanderandL. S. Hegedus'JACS116'8126(1994)'
triphenyls.o Thioamides. Good yields of t u ith chlorothioformamides.?
K. Park,K. Yuan,andW.J. Scott..lO J.-P.Ducoux,P. Le Menez,N. Kuncs andC. Allard L. Hevesi,B. Hermans, 'F. L. Mazzo Babudri,V. Fiandanese, L. L. Shiu,C.-C.Yu, K.-T.Wong.B.'L 1 2 .l 0 l 8 ( l 9 9 3 ) . 'J. J.J. A. Cooney,and M. Ju Clayden, G. Marcha F. Babudri,V. Fiandanese,
G rignard reagents/Palladium cll Coupling with vinylic halidct r rrh retentionof configuration. Sx2 Displacements'1 Regio-
rhosphateshas been observed. Biphenyl synthesis.a Monoar : unctionalization of biphenyl derirr
Grignord reagents/polladiumchloride cornplexes 173 ''H.-J. C r i s t a u , M . - B . G a s c ,a n d X . Y . M b i a n d a , J O M C 4 7 4 ,C l 4 ( 1 9 9 4 ) . 't E . P i e r s , B . W . A . Y e u n g ,a n d F . F . F l e m i n g , C J C 7 1 , 2 8 0 ( 1 9 9 3 ) . HO_
-
:
ano--,/-\AZ
r.:
Grignard reagents/nickel complexes. Coupling with neopentyl iodides.' On treatment with ZnClz and (dppf)NiClr, Grignard reagentscouple with neopentyl iodides. Reaction with enol ethers. 2-Substituteddihydropyrans and dihydrofurans are reduced to the (E)-alkenols2 with isopropylmagnesiumbromide in the presenceof a nickel chloride complex. The reaction has been applied to a formal synthesis of
Ih ,n activating grouP on nitrogen
recifeiolide.
I
837" of la.rr'ner^ involves the displacement a l k y n e s T o f the :c.rction the synthesis
tan3uj, Jmino acids are acquired by 2 ( O x a z o l i d in-2l.,r,z',lrdin-2-ones.'0 compounds' those .:.:l:native route to
Y;-,.jy
r.. ;' \-,1 : . .., ,o : o F.
.-1
Ph \
iPrMgBr
H
^
Y)5HH, \.. " / o Po(on)z'c x o r x p 90"/"
!l'.
lc.: . c addition, making disubstituted p:rr.rred'r indirectly, for example'from is e . rrllithiums' The Sn/Li exchange lor:J', may be Present' l. .. -200
90%
95"/o
z\ ,-)_/ 770/o
'N. I r a n p o o r a n d P . S a l e h i ,S I 1 5 2 ( 1 9 9 4 ) . : K. I. Booker-Milburn and D. F. Thompson , TL 34,'7291 (1993). 3 D . V i l l e m i n a n d F . S a u v a g e tS , L 435 (1994). tS. M u r a t a . K . T e r a m o t o .M . M i u r a , a n d M . N o m u r a , B C S J 6 6 ' 1 2 9 7 ( 1 9 9 3 ) . tM. K a c a n a n d A . M c K i l l o p , S C 2 3 , 2 1 8 5( 1 9 9 3 ) . uD. M . A n t o n o v , L . L B e t e n ' k i i , A . A . D u d i n o v , a n d M . M . K r a y u s h k i n , M C r 3 00 9 9 4 ) . 'R. S . S r i v a s t a v aa n d K . M . N i c h o l a s ,T L 3 5 , 8 ' 1 3 9( 1 9 9 4 ) .
198 Iron(II) sulfate
Iron(lII) chloride, clay-supported' p.ct, oirp"t.ed in silica gel catalyzes the rapid condenDithioacetalization.' sation of ketones with o-benzenebismethanethiol' """";-;;;;;:rlrrn., activiti.esfor the Iron monrmorillonitEshows Bood catalytic acetals and aldimines' synthesis of B-amino esters from silyl ketene
M. van LeeuwenandA. McKillop..lCSl tA. M. Gasco,C. Medana,andA. Gasco
Isocyanuric chloride. a-Perchloro esters.' Oxidatirc < ro chloroalkyl estersthat are also full
'H. K. Patney, SC23, 1829(1993)' 'M. Onuku,h..Ottno,N. Yanagiya' andY' Izumi' sL 141(1993)'
o. Iron(III) Perchlorate. Transesterification't
esters of Ethyl esters from carboxylic acids and acetic
R.
/o-(R'
1oA*
benzylicalcoholsareobtainedinthecatalyzedtransesterificationprocesses,using group' ethyl acetateas the donor of ethoxy or acetyl ' B. Kumar,H. Kumar,and A. Parmar,IJC(B)32B, 292 (1993)' F. Bellisia.M. Boni, F. Ghelfi,andU V Iron(III) "--)ilrir,
PhthalocYanine' with PhNH9H This catalyst effects anilination of alkenes ,^ination.t
inrefluxingPhMe.otherFecatalystscausereductionofthereagenttoanilinetoa great extent.
.V-Isopropylephedrine. En antio selective prot onat ion. ron source for thiol ester enolates. C. Fehr,I. Stempf,andJ. Galindo.AClfl
Fe-phthalocyanins
,NA
rNHPh "nA
P h M e/ N 2 , 4
2- Isopropylapoisopi nocampheylbc E n a n t io selectiv e hydroborat iot -' iignificantly better asymmetricindu boranes.
'M. Johannsen JoC 59'214(1994)' andK. A. Jorgensen,
Iron(II) sulfate. of aromatic halides with enoSxvll reactionsof haloatenes't The displacement NH3 to give arylacetic acid derivatives lates of acetic acid derivatives in liquid (esters,amides,etc.)hasabroadscope'Thereactionisinitiatedbyelectrontransfer. produces o-nitroanilines' The Reduction of benzofuroxans'2 The reduction when PhSH is used as the reducing agent' iron salt may be presentrn catalytic amounts
oFeSOr .7HzO DMSO, H2O rt
[rY*o' \z\nx,
U. P. Dhokte and H. C. Brown, fL J5. I
2-Isopropylapoisopinocampheylborane199
I g.. iltalyzes the raPid condeng,',,J catalytic activiti.esfor the s .rrJ aldimtnes.
' M. van Leeuwen and A. McKillop, ICS(PL) 2433 (1993). tA. M . G a s c o ,C . M e d a n a , a n d A . G a s c o ,S C 2 4 , 2 ' 1 0 7 ( 1 9 9 4 ) .
Isocyanuric
chloride.
\
a-Perchloro esters.' Oxidative cleavageof cyclic acetals by this reagent leads to chloroalkyl estersthat are also fully chlorinatedat the a-position.
cl Oo.tt-7,O t
)rr.r; acids and acetic esters of ln.c-terification processes,using
R
g-zR'
v bl- 1 R ,
t
"',NyN'cr o
*r ^t^
v'
\^/-\
I
ct
DMF
)
X
,o !-* v
|
'R'
X=OH,Cl t : ! ! i
'F. Bellisia,M. Boni, F. Ghelfi,andU. M. Pagnoni,TL35,2961(1994). inr:r,,n of alkeneswith PhNHOH Ir(,i ,'i the reagentto aniline to a
/
NHPh
N-lsopropylephedri ne. Enantioselective protonation.' ton source for thiol ester enolates.
This chiral amino alcohol is an excellent pro-
' C. Fehr,l. Stempf,andJ. Galindo,ACIEE 32, 1042(1993).
a:: >
-E'.
mc: t ,'f aromatichalideswith enoo ::\e arylacetic acid derivatives nr .- rnitiatedby electrontransfer' 1-1 produceso-nitroanilines' The PhSH rs usedas the reducingagent'
\'-Noa j?,Naz t co"'o
2-Isopropylapoisopi nocampheylborane. Enantioselective hydroboration.t This bulkier chiral borane i-PraBHz achieves significantly better asymmetricinduction than those realized by IpcBH2 and related boranes.
6*, (1994). U. P. DhokteandH. C. Brown,7Z 35,4'115
Ketene. Acetylation.t This reagent effects rapid c-acetylation of B-diketone cu(II) chelatesat room temperature in CHCI: (75-95Vo yield). Contrarily, the use of acetyl chlorides (and other acyl chlorides) leads to a mixture of C- and O-acetyl derivatives'
Lanthanum(III) bromide. Benzyl esters.t Benzyl ab presenceof LaBrr. Other lanthe 'Y. JiangandY. Yuan,SC24, l(Xj
'G. J. Matare,A. Bohac,andP. Hrnciar,S 381(1994)'
Ketene acetals. A general preparativeprocedurerconsists ofpassing HCI through a stoichiometric etherealmixture of a nitrile and an alcohol (2 OH per CN) at 0'C and treatment of the adducts with NaOMe. Both acyclic and cyclic ketene acetals are obtainable' lA. B. Argadeand B. R. Joglekar,SC 23, 19'19(1993).
Lanthanum(III) chloride. B-AIkoxy carboxylic aciltacids is catalyzed by La(III) gl
andH, rrr J. A. Peters, J. Huskens.
Lanthanum(III) isoproporila p-Cyanohydrins.t Group
Ketene r-butyldimethylsilyl methyl acetal. Pummerer reanangernen| Sulfoxides are converted into a-siloxy sulfides,' in which the new O-C bond is anti to the original S-O bond. Accordingly, the rearrangementof chiral sulfoxides is enantioselective.The method is applicable to syn-
curs in the presenceof Ln(lll) r
thesisof B-lactam Precursors.t
Lanthanum(III) tris-F-dikar Thc Selective alkylation.t in thc differentiated be clearly (iilc methylation amine undergo
Meo\
ra\ *"-?.,.1) J+i,
^trr-
\z\
}1-70'l. (> 99o/. ee)
'Y. Kita, N. Shibata,S. Fukui, andS. Fujita,TL 35' 9733(1994)' ty. Kita. N. Shibata, TL 36, ll5 (1995)' N. Kawano,T. Tohjo,C. Fujimori,andK. Matsumoto,
'
H. Ohno,A. Mori, andS. Inorr. (
unchanged. Hydrogenation.2 With ler enonescan be selectively redrrc I.V. Komarov,V. E. Denisenko,I tl.V. Komarov,V.E. Deniscnko, e
Lead(IV) ecetate. 13, 155-156 Cleavage of N-substituteJ 1 irom such derivatives bearing c 4- Oxopentylation of hctc ,ring cleavage) in the prescno r ields of the products. The rer eroaromatics.Manganese(IIl) r
Cu(II) C-i. .r \ lation of B-diketone r.c.J ContrarilY,the use of acetYl ,:.,.
,,f C- and O-acelyl derivatives'
Lanthanum(III) bromide. BenZyl esters.t Benzyl ethers can be used to esterify carboxylic acids in the presenceof LaBrr. Other lanthanoid bromides (Nd, Sm, Dy, Er) are also effective. 'Y. JiangandY. Yuan,SC24, 1045(1994)'
I
p3\-:ns HCI through a stoichiometric the { nc: C\ ) at OoCand treatmentof atenr ucetalsare obtainable'
Lanthanum(III) chloride. p-Alkoxy carboxllic acids.t The Michael addition of alcohols to unsaturated acids is catalyzed by La(III) salts. 'J. Huskens, and H. van Bekkum,T 49,3149(1993). J. A. Peters,
Lanthanum(Ill) isopropoxide. 17, 160 p-Cyanohydrins,t Group transfer from acetone cyanohydrin to epoxides occurs in the presenceof Ln(III) alkoxides. r:rcrtedinto a-siloxy sulfides" in the rear6 i :'O bond. AccordinglY' The method is aPPlicableto syn-
'H. Ohno,A. Mori, andS. Inoue,CL9'15(1993).
ir.
-:?'D-
i'i'70"6 (> 99% €e)
t. --:1 199'1). , L 36' I l5 (1995)' , 1 J K M a t s u m o t oT r
Lanthanum(III) tris-F-diketonates. Selectivealkylation.t The reactivities of amines toward alkylating agents can be clearly differentiated in the presence of a lanthanide complex. Thus a tertiary amine undergomethylation(MeI or MezSOa),while a primary amino group remains unchanged. Hydrogenation.2 With lanthanum(Ill) tris-B-diketonates, the C:C enonescan be selectivelyreduced in a catalytic hydrogenationprotocol'
bond in
'1.V.Komarov.V. E. Denisenko, andM. Yu. Kornilov,T 49,7593(1993). tf .V. Komarov,V. E. Denisenko,and M. Yu. Kornilov,T S0' 6921(1994)'
Lead(IV) acetate. 13, 155-156; 14, 188;16,193-194 cleavage of N-substituted phenylglycinols.t The generationof primary amines from such derivatives bearing chiral substitutentsproceeds without racemization. 4-Oxopentylation of heteroaromatics.2 The oxidation of 1-methylcyclobutanol (ring cleavage) in the presence of pyridine and related substancesleads to useful yields of the products. The reaction involves radical substitution on protonated heteroaromatics.Manganese(Ill) acetate is a comparable reagent. 20r
202 Lipases
Ho-b
O
Pb(OAc)a HOAC, 80-l0oo
67"/" (2.75:1l Dioxycarbenes.3 A method for the carbene generation involves oxidation of methyl dimethylhydrazonocarboxylate,alcoholysis, and pyrolysis.
Pb(OAc)4
F"**co,r"
cH2ct2
MeQ oac
-x N{ i l o
BOH
A
RO MeO
60-721o a Saturated alcohols form D-lactoneson reaction with Remote carbonylation Pb(OAc)aand carbon monoxide.
o
af>
M-)
oH
Pb(OAc)4
co / PhH 400
af\^o
l ( | fl-4':-z H
|
'M. K. MokhallalatiandL. N. Pridgen,SC23, 2055(1993). 'G. L Nikishin,L. L. Sokova,andN. I. Kapustina, DoK 326,205(1992). tK. Kasram,D. L. Pole,M. El-Saidi,andJ. Warkentin, JACSl16, l16l (1994). oS.Tsunoi,I. Ryu, and N. Sonoda,JACS116,54'13(1994).
Lead(IV) acetate-copper(II) acetate. Dehydrogenation.t 2-(Alkoxycarbonyl)- and 2-(aminocarbonyl)cycloalkanones are converted to the cycloalkenoneswith the mixed acetatesin refluxing benzene. 'A. G. SchultzandM. A. Holoboski.TL 34,3021(1993).
Lipases. Hydrolysis.
The list includes acetatesof primary alcohols adjacentto a stereodimethyl trans-aziridine-2,3-dicarboxycenter,lmethyl 3-hydroxyalk-2-enoates,2 late,3 acetatesof secondary alcoholsainctuding the homoallylic type,5 4-substituted oxazolin-5-ones,6and 1-chloroacetoxybicyclo[4.1.0]heptane.?
Resolution by tran sesterif icat iot. hols,8propargyl alcohols,e2-phenylthro hydroxy-2-hexenoates,12 and 2-substr esterification provides a means of scpe also resolvedby lipase-mediatedenan Other esters that have also been us iluoroethyl propionate.rs'16 There is a rc cationrTof racemic trifluoroethyl estcr
Malonic estersare desymmetrized chiral carboxylic estersare obtainedfr boxylic carbonic anhydrides.re Chemoselective tran sester if icatia of carbohydrates,2o the 2-OH of 4.6-0l of 1,3-naphthalenediol22 has been obsc only moderate (3-OAc : l-OAc : 1,3-(OA
Amidation of esterc, Acrylic:' e well as N,N'-diacyldiamines26 are rl diestersare converted to N-aminosucc B-Hydroxy esters give equimolar r
resolved esters.2E The former compoul alcohols.Racemic amines, like alcoh (ion2eor N-alkoxycarbonylation.{
T. Matsumoto.Y. Takeda.E. Iwata.M S :P. AIlevi, M. Anastasia, P. Ciuffreda.eo 'M. Bucciarelli, A. Forni.I. Moretti.F. P 'Y. Naoshima, M. Kamezawa, H. Tachrb JCS(P1)5s'1(1993). 'Y.-C. Pai,J.-M. Fang,andS.-H.Wu..lO ^J.2. Crich,R. Brieva,P. Marquart.R -l (1993). 'J.-P. Barnier,L. Blanco,G. Rousseau. E 'N.W. BoazandR. L. Zimmerman,IA 5. 'P. Allevi, M. Anastasia,F. Cajone.P-Ci "'T. Fukazawaand T. Hashimoto,IA rl. ll " L.T. KanervaandO. Sundholm, JCSTP tH. M. Takano,andl Akita, l. Umezawa, 'T. Itoh,J. Chika,Y. Takagi,andS. Nisb '' M. Pozoand V. Gotor,T 49, 10725 ll99: 'V. S. Parmar.R. Sinha,K. S. Bisht,S.Gr uL.T. KanervaandE. Vanttinen,IA 4. tj 'F. Theil,A. Kunath,M. Ramm,T. Rabr 'tM. ShapiraandA. L. Gutman,IA 5, l6t '8. andM. Bassir,fL 35.{ Guibe-Jampel 'R. Pulidoand V. Gotor, CR 252,55 ( 19, t' L. Panza,M. Luisetti,E. Crociati,andS
LiPases203
a-,. i2.75:1)
involves oxidation of
i.::-rittion
r. r1J Fvrolysis'
\leo
,oR
N;(
d
O +
\< /\
^
Rq '
ued
t,.::r d-lactoneson reaction with
o ll -tt--,/r^'O
..-'l.\///
l
r
67" o
lv. '
)A -r:6 :05 (1992). ! - { ( \ l 1 6 .l 1 6 l ( 1 9 9 4 ) ' 9.:
lnJ :-(aminocarbonyl)cycloalkanon:: rr'J lcetatesin refluxing benzene' 9:
rlmrr\ alcoholsadjacentto a stereon\\ . I rans -aziridine-2,3-dicarboxyrhe homoallylic type,54-substituted .l ,, heptane.?
Resolutioniy transesterification. Using vinylic acetatesto esterify allyl alcohols,Epropargyl alcohols,e2-phenylthiocycloalkanols,r0a-hydroxy esters,rrmethyl 5the enantioselective and 2-substituted 1,3-propanediols,13 hydroxy-2-hexenoates,12 Vinyl carbonatesare isomers. optical of of separation esterification provides a means carbonates'ra to benzyl conversion enantioselective also resolved by lipase-mediated 2,2,2-triinclude resolution kinetic in the used been Other esters that have also transesterifienantioselective on a double report is a There fluoroethyl propionate.rs'r6 cationrTof racemic trifluoroethyl esters and cyclic meso-diolsby lipase catalysis. Malonic esters are desymmetrized by exchangeof one of the ester groups,rsand chiral carboxylic estersare obtained from lipase-mediatedalcoholysis of mixed carre boxylic carbonic anhydrides. Chemoselectivetransesterification. The esterification of the primary alcohol the 2-OH of 4,6-O-benzylideneglycopyranosides,2rand the 3-OH of carbohydrates,2o has been observed,although in the last casethe selectivity is of 1,3-naphthalenediol22 (3-OAc: l-OAc: 1,3-(OAc)z:80:16:4). only moderate Amidation of esters. Acrylic2s and B-keto amides,2aprotected dipeptides,2sas well as N,N'-diacyldiamines26 are accessible by the enzymatic method. Succinic diestersare converted to N-aminosuccinimides2?by hydrazines' 3-hydroxyamides and the B-Hydroxy esters give equimolar mixtures of chiral synthesis of 1,3-amino the for are useful resolved esters.28The former compounds acetylaenantioselective by resolved are alcohols. Racemic amines, like alcohols, tion2eor N-alkoxycarbonylation.30 lT. Marsumoto, y. Takeda,E. Iwata,M. Sakamoto, andT. Ishida,CPB42, ll9l (1994). rP. Allevi, M. Anastasia, P. Ciuffreda,andA'M. Sanvito,TA4'1397 (1993)' rM. Bucciarelli, 3041(1993)' A. Forni,I. Moretti,F. Prati,andG. Torre,JCS(P1) I Y. Naoshima, T' Fujita,K Kihara'andT' Raku' Y. Munakata, H' Tachibana, M. Kamezawa, JCS(PI)557(1993). tY.-C. Pai,J.-M.Fang,andS.-H.Wu,JoC 59' 6018(1994). oJ.Z. Crich,R. Brieva,P. Marquart,R.-L' Gu, S. Flemming,and C'J' Sih' "/oC 58' 3252 ( l 993). tJ.-p.Barnier,L. Blanco,G. Rousseau, "/OC58, 1570(1993). andI. Fresse, E. Guibe-Jampel, 'N.W. BoazandR. L. Zimmerman,TA 5, 153(1994). 'P. Allevi, M. Anastasia, F. Cajone,P. Ciuffreda,andA. M' Sanvito,TA 5' 13(1994)' 'nT.Fukazawa TA 4,2323 (1993). andT. Hashimoto, 'L.T. KanervaandO. Sundholm'JCS(PI)2407(1993). 'tH. Akita, I. Umezawa, M. Takano,andT. Oishi,CPB 4l' 680(1993). 'tT. Itoh,J. Chika,Y. Takagi,andS. Nishiyama' JOC 58,5'll'l (1993)' '' M. Pozoand V. Gotor,T 49, 10725(1993). ,5v. s. parmar,R. Sinha,K. S. Bisht,S. Gupta,A. K. Prasad, T 49,4107(1993). andP.Taneja, ' u L . T .K a n e r v a n dE . V a n t t i n e n , T4A, 8 5 ( 1 9 9 3 ) ' ''F. Theil.A. Kunath,M. Ramm,T. Reiher,andH' Schick,JCS(PI)1509(1994)' '8M. ShapiraandA. L. Gutman,?A 5, 1689(1994). '8. Guibe-Jampel andM. Bassir,IL 35,421(1994). 'R. Pulidoandv. Gotor'CR252,55(1994);JCS(PI)589(1993)' t' L. Panza,M. Luisetti,E. Crociati,andS. Riva,JCC 12' 125(1993).
204 LithiophosPhine (1993)' 22D. L a m b u s t a ,G . N i c o l o s i , M . P i a t t e l l i , a n d C . S a n f i l i p p o , I J C ( B ) 3 2 8 ' 5 8 ttS. Puertas, R. Brieva, F. Rebolledo, and V. Gotor, T 49' 400'l (1993)' 2nM. J . G a r c i a , F . R e b o l l e d o ,a n d V . G o t o r , f 5 0 ' 6 9 3 5 ( 1 9 9 4 ) . ? 5 K . K a w a s h i r o , K . K a i s o , D . M i n a t o , S . S u g i y a m a ,a n d H . H a y a s h i , T 4 9 , 4 5 4 l ( 1 9 9 3 ) . "C. Astorga, F. Rebolledo, and V. Gotor, JCS(Pl) 829 (1994)' "C. Astorga, F. Rebolledo' and V. Gotor, S 287 (1993)' 28 M. J. Garcia, F. Rebolledo, and V. Gotor, TA 4,2199 (1993). " M . T . R e e t z a n d C . D r e i s b a c h ,C h i m i a 4 8 , 5 7 0 ( 1 9 9 4 ) ' 'oM. Pozo and V. Gotor, T 49,4321 (1993).
2-Lithiothiazole. Formyl anion equivalent.' 2-Lrt pounds. Degradation of the heteroclcl dride reduction, and hydrolysis (HgCl D\
u{)
Bn.r,Boc BnAcooMe
,::':
*"
c-Lithioalkyl dimesitylborane. 13, 8 Alkenes.t The a-boryl carbanions react with carbonyl compounds to afford are trapped alkenes. The reagentis (E)-selectivefor ArCHO when the intermediates leads to TFAA with Treatment HF-MeCN. with MerSiCl and then treated with aq. are they aldehydes (E)-alkenes atiphatic from (Z)-alkenes mainly. For generationof lithioalkylboranes'2 the (e.g., to CF.SO.H) added together with a protic acid are Ketones.3 when the adducts from the lithioalkylboranes and aldehydes furnishes MeszBCHzLi that except treated with TFAA or NCS, ketones are formed,
5-Lithiomethyl-3-methylisoxazolc Benzoisothiazoles.tAnnulatron bonyl compoundsprobablyprocecd
I -al kenes.
tization.
Ph
J
"nFo.a" . 99%de, 97% ee)
These are gr esters.':coa chloromethylphosphonic saturateda-aminonitriles,15phospl Assorted anions,
derived from c.r-haloalkanecarboxll i of a synthesisof N-Boc cyclic imino r are unstable i methyl-2-oxazolinesre evenat -75"C.
213 LithiumdiisoProPYlamide N-Protected iminodiacetic esters readily yield 1,3-dianions,rwhich are useful or:Jr'\ the nucleophilein the derivar. l.'rtormed in the Presenceof a U l':'
3\ [ . rr ith CO gives a reagentthat is D r J r n : l r .i t c a n b e u s e dt o s y n t h e s i z e s1i. \'-phenyl imidates to N-silYl r3:i('ment at room temperature.
nucleophiles. 2-Arenesulfonyl benzamides are deprotonated in a reDirected lithiation. in good yields gioselectivefashion, furnishing thioxanthen-9-one10,10-dioxidesa directed omanifest compounds, iodo the (57-96Vo).3-Halopyridines,including be noted It should (at electrophiles.s with C-4) reaction lithiation and regioselective BuLi or either with on treatment generates 3,4-pyridyne that 3-chloro-4-iodopyridine r-BuLi. Halogendance is also observed'n Vinyl esters are silylated at the trigonal a-carbon, making available the enol esters of silyl ketones.TThe regioselectivedeprotonation of B-alkoxyacrylic esters and the ability of the lithio derivative to undergo a tandem Michael-Julia condensation with suitable acceptorsare exploitable in the synthesis of highly functionalized cyclopentenones.8
o
2oo
o2
rcooEt LDA/THF, .9OO
Ph{
1-SOzPh ETOOCJ/
tr. i39: 16,196-197; 17' 165-167 rr:rrrro of (E)- and (Z)-ketene silyl D jr'ncrated from conjugate esters by rlrJ. r\ present,they are quenchedby t"::,'nr of the SAMP/RAMP hYdraUun.carboxylicesters2with l_- .,.:','t'
osiMeT
707"(E:Z >99 1 ) MeOOC\/.\ l-) \
- . v \,Asorpn
cooEt
\
r
+
54"/"
(>99"/.de, 97% ee)
LDA / THF
L-62"k
ao-\
SMPU
-
Ph-\
Alkenyl aryl sulfoxides are also deprotonated at the a-carbon, and the subsequent reaction with aldehydesis diastereoselective.q Cyclopropanation.to When a ketone or nitrile and 2-phenylsulfonyl-1,3-cyclohexadieneare mixed with LDA, a twofold reaction (Michael + SN2)occurs.
THF;
\le35iCl
-:
ll ),,so,pn
?--a
55"/" 2:1) (ratioot diast€reomers
I9 9 3) .
.fA
-4
These are generated by deprotonation of allylic halides,rl chiral carbamates,'tunesters,r2conjugatedhydrazones,13 chloromethylphosphonic The dianions sulfonamides.rt and phosphonamides,16 saturated a-aminonitriles,15 the basis forms reaction this and cyclize, acids derived from ar-haloalkanecarboxylic Assorted anions.
The conjugatebasesof 2-(arylmethoxy)of a synthesisof N-Boc cyclic imino acids.rE as are unstable methyl-Z-oxazolinesre [2,3]sigmatropic rearrangement takes place -75'C. even at
triamide 214 Lithium diisopropylarnide-hexamethylphosphoric LDA, THF
o1
o.-/--*K
-750,3.5h
riY l l
l
t
or
\Zf-rl'\
)
/
D . D u g a t , D . G a r d e t t e ,J . - C . G r a m a i n , a n d B I 'P. D o w d a n d B . K . W i l k , S C 2 3 , 2 3 O 7( 1 9 9 3 t 'K. K a t o , H . S u e m u n ea, n d K . S a k a i , I 5 0 . 3 1 1 1 'M.-C. P . Y e h , B . A . S h e u ,H . - W . F u , S . - 1 .T a u .
OH 70"/"
'J. Otera,Y. Fujita,andS. Fukuzumi,SL2l3 (1994). 'D. Enders,H. J. Scherer,and J. Runsink,CB 126, 1929(1993). tJ. Einhorn,C. Einhorn,andJ.-L. Pierre,SL 1023(1994\. aF.Beaulieu JOC 59,6508(1994). andV. Snieckus, t c . w . G r i b b l ea n dM . G . S a u l n i eH r ,3 5 , 1 5 l ( 1 9 9 3 ) . oRocca,C. Cochennec, M. Mallet, A. Godard,and F. Marsais,L. Thomas-dit-Dumont, G. Queguiner,JOC 58,7832(1993). 's.w. wright, ra 3s, l84l (1994). tA. Datraand R. R. Schmidt,TL 34, 416l (1993). nJ.Fawcett. JCS(Pl)6'7(1993). andD. R. Russell, S. House,P.R. Jenkins,N. J. Lawrence, '0A.M. Ericsson, N. A. Plobeck,andJ.-8. Biickvall,ACS48, 252 (1994). " M. Julia,J.-N.Verpeaux, BSCFf31, 539(1994). andT. Zahneisen, 12S.Berte-Verrando, F. Nief, C. Patois,and P. Savignac,JCS(PI)821(1994). 13M.Yamashita, andK. Nakano,BCSJ66, 1759(1993). K. Matsumiya, 'oS.S.C. KochandA. R. Chamberlin, JOC 58,2725(1993). 'tC.-J.Chang,J.-M. Fang,andL.-F. Liao,JoC 58, 1754(1993). '6V.J. Blazis,K. J. Koeller,andC. D. Spilling,TA 5,499 (1994). 'tF. A. Davis,P. Zhou,andP.J.Carroll,JOC 58,4890(1993). 'tA. De Nicola.C. Einhorn,J. Einhorn,andJ. L. Luche,CC 8'19(1994). ''K. KamataandM. Terashima, CC 2771(1994\. triamide. Lithium diisopropylamide-hexamethylphosphoric Enolization.t N-Aryl enaminones are enolized toward the a'-position despite the presenceof HMPA. For alkylation at the 7-carbon it is necessary to use LiNlSiMer)z as the base. A general approach to itaconic estersz is via the a-dimethylaminomethylsuccinates,which are formed by alkylation of B-dimethylaminopropionic esterswith a bromoacetate. 1,4-Asymmetricinduction is evident in the alkylationsof chiral cyclic acetalsof esters. cycloalkanone-2-carboxylic Attack of a remote ester enolate onto a diene-Fe(COh complex under a CO atmosphere leads to a cyclic product. Fused and bridged ring systems can thus be
Lithium diisopropylamide-potassiumr-l Epoxide isomerization' This stmng allylicalcohols. The regiochemistry of thc mal heteroatomin the substrate.
rt
I S. AidhenandR. Brasl: D. Enders, K.-J.Heider.er LTMP /THF Ms3SiCl - 1000-> rt
61"/"
,osiMes TBSO
OMe
82/"
Directed lithiation, The nitrogen atom of aromatic aldimines assiststhe deprotonation at a proximal benzylic position by LTMP.T The resulting lithium derivatives are nucleophilic and synthetically useful for elaboration of isoquinolines.a
oc"e
-oupling with aryl iodid
l- ith ium tri-s-butylbon
r 5 .r 9 2 - 1 9 3
Demethylation.t Ar :he cleavageof aryl meth
C. Majetich,Y. Zhang,arl
l- ith ium trimethylsilyld Helerocycles. Borh
LTMP / THF
3-siloxy ketonesand ofcl nrolve condensationwirt n\ertion.
BCON(OMe)Ms rt
(R=nBu) 83o/"
Dianions of B-enamino ketones.s The deprotonation is complete at room temperature, but the subsequentalkylation (e.g., with aldehydes)should be conducted at a lower temperature (-70'C).
2'''/l (/
221 Lithium trimethylsilyldiazomethane
t is made Posln::.i F\ an amine in MeCN yields' ^,,1. 85-987o in obtained are rl. F)tlcneacetals.t The anion furnishes and system rai::-.'ntationof the dioxolane
K. Yasue,and H. Yamamoto,CC 2103(1994). A. Yanagisawa, 'K. HartoriandH. Yamamoto, JOC58, 5301(1993);r 50, 3099(1994). 'L. andD. S. Carter,JOC 58,2463(1993). A. Flippin,J. M. Muchowski, 'L. JOC 58,2631(1993). A. FlippinandJ. M. Muchowski, 'G. Bartoli,M. Bosco,C. Cimarelli,R. Dalpozzo,andG. Palmieri,T49,252l(1993).
Lithium tetramethylthallate. 17, 172 I,2-Addition to enones.t This methylating agent can discriminate an enone rnd a ketone, favoring the former. The reversechemoselectivity may be due to the operation of a single-electrontransfer mechanism.
r i. -r5.761( 1994)' ).r 171-172 LTuP). 13, 167; 14,194-195;17' initiated is compounds r.:.:'\n ro carbonyl side of an dc::i hase the less substituted to give tends -r',no\ubstituted epoxide t\ j on thc rr: - ,'i estersis highly dependent a-t-butyldi' methyl of i: :- rhe silylation (E)-isomer r i i 1c'reaction conditions: The and -: !r.: i i'r l it h ium tetramethylpiperidide' of presence the in lr-.J:methylsilyl chloride
I E. MarkoandC.W.Leung,JACS116,371(1994).
Lithium trialkylstannate. Altenyl stannanes,t The Siy2' displacementof propargyl tosylates in the prescnce of CuBr . SMez provides allenyl stannanes,which, by virtue of Pd(0)-catalyzed :oupling with aryl iodides, are important precursorsfor arylallenes. p-Trialkylstannylcyclohexanones.' Conjugated chiral (SAMP) hydrazones mpose attack by organostannane reagents diastereoselectivelyand enantioselec:rrely. The adductsare nucleophilic,thus allowing substitutionat C-2. Entry of the :lectrophile trans to the tin residue is favored. SC 24,789(1994). I S. AidhenandR. Braslau, K.-J.Heider.andG. Raabe,ACIEE32,598(1993). D Enders.
t \
.rur,,", lve
Mqsicl
;1t'u* OMe
TBSO
' 10Oo -> rl
82"/"
the deprol(':- ,,1aromatic aldimines assists derivativcr lithium resulting br t.T\lP.' The I i,,: cl.rborationof isoquinolines'a
Lithium tri-s-butylborohydride (L-selectride). 13, 167-168;14, 195-196;
ts. t92-193 Demethylation.t An unconventional application of the bulky reducing agent is :rc cleavageof aryl methyl ethers (68-100% yield). J Majetich,Y. Zhang,and K. Wheless,TL 35,8"12'l(1994).
L ithium trimethylsilyldiazomethane. Heterocycles. Both the formation of 5-trimethylsilyl-2,3-dihydrofuransr from i-siloxy ketonesand of cycloheptapyrrolones2from N-methylanilides of a-keto acids :rrolve condensationwith the ketone group and subsequentSrv2reaction or carbene
car. lr.r€ Me
:rsertion. $% (R=rFBu)
r 3
*.,z\ room temT:.': Jeprotonation is complete at ar conducted r. i $ rth aldehydes)should be
tl
MqSiC(Li)N2 EtzO -780->A
I
ll' t A
222 Lithium tris(methylthio)methide 'K. Miwa, T. Aoyama, and T. Shioiri, SL 461 (1994). tH. O g a w a ,T . A o y a m a , a n d T . S h i o i r i , 5 L 7 5 7 ( 1 9 9 4 ) .
Lithium triorganozincates. Halogen-zinc exchange, Haloarenes are converted by Me:ZnLi to arylzinc nucleophiles.rReaction of the latter with carbonyl compounds gives benzylic alcohols. Analogously, propargylic substratesgive allenylzinc reagentsthat are sourcesof homopropargylic alcohols.2 Silylzincate reagents are superior to silylcuprates in Conjugate addition.l in the addition to the a,B-unsaturatedcarbonyl compounds. efficiency terms of their lY. Kondo,N. Takazawa, JOC 59,4717(1994). C. Yamazaki,andT. Sakamoto, 2T.Katsuhira, T. Harada,K. Maejima,A. Osada,andA. Oku,JOC 58' 6166(1993). tR. A. N. C. Crump,l. Fleming,andC. J. Urch,JC.S(P1) 701(1994).
Lithium tris(t-alkoxy)aluminum hydride. a-Amino aldehydes. N-Boc a-amino phenyl estersr and carboxyanhydrides2 are reduced to aldehydesin THF. chiral a-hydroxy acids.s a-Keto esters of cis-3-tosylaminoisoborneolare reduced stereoselectively.The chiral auxiliary can be removed by LiOH in aqueous
Homologous thioesters.2 Bcsi , methylthio)alkanes derived from r esters.The transformationis acco * ith aqueousHBFr in DMSO ar t3{
r-.A. Abood,SC23, 8ll (1993). 'V. Barbero, S. Cadamuro, L DeganrI
Lithium tris(phenylthio)merh ilc. Ipso anion precursor,t Nuck products that readily subrnit a PhS resultinglithio compoundsare acrl
o II
('>-\J]
(Phs)3cLi/ THF
(
-7go : s-BuLi / THF
I
THF at room temperature without racemization.
T Cohen, K. McNamara, M. A. Kuzcr NHTs
NHTs
o
l i ^ . ot'\\.,Hn tl
LiArH(ocEr3)3 THF,
OO
o
o ll
o-vPh : OH
97"/.
Stereoselective reduction of cyclic ketones.a Conformationally rigid ketones are reduced from the less hindered equatorial direction by the very bulky tris(lbutyldiethylmethoxy)aluminum hydride reagent. Thus 4-l-butylcyclohexanone furin a 95:5 ratio. nishesa mixture of cis- and trct?.s-alcohols 'P. Zlatoidsky, HCA 77,150(1994). 'J.A. Fehrentz, C. Pothion,J.-C.Califano,A. Loffet,andJ. Martinez'TL35'9031(1994). tY. B. Xiang,K. Snow,andM. Belley,JOC 58,993(1993). nG. Boireau,A. Deberly,andR. Toneva,SL 585(1993).
Lithium tris(methylth io)methide. B-Hydroxy esters.t Epoxide ring opening with LiC(SMeh with subsequenthydrolysis (mediated by HgO-HgCl2) complementsthe conventional method involving formation of B-cyanohydrins. The overall yields of the new method are good; however, the reagentsare much more expensive.
r9 9 3 ) .
223 Lithiumtris(phenylthio)methide Homologous thioesters,2 Besides complete hydrolysis to give esters, 1,1,I-tris(methylthio)alkanes derived from alkyl halides can also be a source of methylthio esters. The transformation is accomplished by heating the tris(methylthio)alkanes
)q: 9-j
with aqueousHBFa in DMSO at 130'C. 313 -r,n\€tt€d by Me3ZnLi to arylzinc alcorr^ r\l compoundsgives benzylic of sources are that reagents rc ,. cn1lzinc in a j i ^ r . r r e s u p e r i o rt o s i l y l c u p r a t e s compounds' carbonyl hc'. J-unsaturated S:., :'"ttr. JOC 59,47l'7(1994)' (1993)' r . - . : \ O k u ,J O C5 8 ,6 1 6 6 , , r \ r , .,r l 0 l ( 1 9 9 4 ) .
o :-':nr l estersrand carboxyanhydrides2
rr)
Lithium tris(phenylthio)methide. Ipso anion precursor.t Nucleophilic homologation of the reagent generates productsthat readily submit a PhS unit to anothernucleophile(e.g., sec-BuLi). The resulting lithio compounds are acyl anion or methylene anion equivalents.
oLi ll
?.
lc:
'N.A. AboodS , C2 3 ,8 l l ( 1 9 9 3 ) . rM. Barbero,S. Cadamuro, (1993). andR' Fochi,JCS(Pl)2075 I. Degani,S. Dughera,
are re't r'is-3-tosylaminoisoborneol aqueous in LiOH bY removed ..rn be
(Phs)3cLi / THF -78o i s-BuLi / THF
6-
1,,1i Phs/\sPh
o a\ 250
H
91% (>99'/" ee)
M Bordoloi,fL 34, l68l (19931 t M Bordoloi, CC 922 (1993)-
*
Magnesium-mercurY(Il) cL DesulfonYlation.l
H
o
a{ x"*"oo*"
OH Mg -HgCl2 MeOH - 2go
r--{l,,,,,, \--j".,,,."oot"
98% (4'32:1)
(e'g" epoxide) suffers sufficient leaving ability Note that a 7-substituent with conditions.5 reductive removal under these
224
,^q
chlorlde 225 Magnesium-mercury(II) Reiluctive coupling. Using Mg as a sacrificial anode to perform electrolysis, aromatic estersare reduced to benzils6 and isothiocyanate estersto dithiooxamides.T Stannylation of organohalides.E Magnesium together with PbBr2 promotes coupling of allyl, vinyl, propargyl, and aryl halides with BurSnCl in THF at room temperature.The unsaturatedstannanesare obtained in 66-99Vo yield.
I)renesare metallatedbY treata n rr' prePared bY the subsequent Itl
/f
'M.w. Sell,H. Xiong,andR. D. Rieke,ZL 34,600'1,60ll(1993). 'Y.-C. Xu, E. Lebeau,andC. Walker,TL35,6207(1994). tZ.-Y. Wei andE. E. Knaus,IL 34, 4439(1993). oc.H. Lee,E. B. Choi,E. Lee,andC.S. Pak,JOC 59, 1428(1994). tC. S. Pak,E. Lee,andG. H. Lee,JoC 58,1523(1993). oM. Heintz,M. Devaud,H. Hebri,E. Dunach,andM. Troupel ,T49,2249 (1993). 'Y.-P. Xiao andM.-2. Bei, YH 13,84 (1993). oH. Tanaka,A.K.M. abdulHai, H. Ogawa,andS. Torii, SI 835(1993).
o
\.:. r.-rctionwith Mg in methanolat I r:rr:hodpertains to its selectivity: c T,, cleaveone group from a PolYkr^.: Otherwise an excessof Mg is r n , ' :. r n b e d i l u t e d w i t h T H F ' c : r l c r t u r e so f a s u b s t r a t em a y i n -',,ro-2-alkenoatesais observed' ot
Magnesium-cadmium chloride-water. Reductions.t A numberof functionalgroupsare rapidly reducedby this system, which includesacid chlorides,benzyl halides,epoxides,and carbonylcompounds.THF is usedas cosolvent. are observed. Ketonesfrom nitroalkenes.2 Someselectives
Noe
Mg -cd'2 H2O/ THF 15 min
Aco
.-Q,, H 91q. (>99%ee)
'M. Bordoloi, 7L 34, 168l(1993). rM. Bordoloi, CC922(1993).
Magnesium-mercury(II) chloride. Desulfonylation.l
rc'.ri
O"?
Mg- HgCl2
a.rrr
rbility (e.g., epoxide) suffers
;;* 2
,ntt/Y h
l
98%
Magnesiumbromide
Phenytsulfidesfrom sulfoxides.2 /-(o
soPh
U.r,,"'./
p h O '"\"s
Mg -HgC12 MeOH -430,3h
o,,
€rp
TsN"-t"Yph
sPh
/-.e'
o
Ar ( \-J
)-cooEt
Methoxyrnethylenetriphenylphosphorane. (E)-4-Hydroxyalk-2-enals.' The Wittig reaction with 2,3-epoxy aldehydes leads to unstable enol ethers, which are rapidly hydrolyzed. Since the epoxy aldehydes are available in chiral form from the allylic alcohols through Sharplessepoxidation and oxidation, 4-hydroxyalkenals with desired absolute configuration at the carbinol center are easily established.
OH
Ph3P=CHOMe
1nc:.CC2597(1994)'l-carboxYlicesters. firrrl elycinesynthon(l) with a t-butyl [!n,r acidsare recoveredfrom hydroly-
"{""o
I 'oAZl '
I.BUOK/ THF -780-> 250
cHo
80o/. (R=Ph)
'L. Yu andZ.Wang,CC 232(1993).
F. IN- (2- Methoxymethyl)pyrrolidinyl]n itroethene. Chiral Michael acceptor. The chiral auxiliary of this nitroenamine (l) deternimines the stereochemicalcourseof Michael reactionsrsuch that enantioselective troolefination (e.g., with lactone enolates)becomes a reality.
CIZnO
t . , /< o. I
ide. hr. easily handled hydroperoxidewith l .rre relectively hydrolyzed in aqueous rrcl.J b;- ozonolysisof 2,3-dimethyl-2by Jrlurion with water, extraction with d rhat rhe simpler 2-methoxyprop-2-yl
DME, -780
o o
)Ll.\ l
No,
5L"".
82"/. (56"/"ee)
(1)
' M. Node,R. Kurosaki,K. Hosomi,T. Inoue,K. Nishide,T. Ohmori,and K. Fuji, TL 36,99 (l99s).
236 Methylaluminum 1,1'-bi(2,2"naphthoxlde)
2-(4-MethoxYPhenYl)ethanol. protection of carboxylic acids.t Esters are prepared using DCC-DMAP, and ot room temperathey are cleaved on contact withl%o trifluoroacetic acid in cHzcl2 estersand t-Boc t-butyl affect not do conditions deblocking ture for a short time. The
cHo
+
:C=O
amines. ' M. S. Bernato*icz,H.-G.Chao'andG. R. Matsueda, TL 35' 165l(1994)' Y . T a m a i , M . S o m e y a ,J . F u k u m o t o . S
l.-Methoxy-3-trimethylsiloxy'1,3-butadiene' Trichlorotropones,tThe Diels-Alder reaction with tetrachlorocyclopropene is isolatedin 56Voyield' 3,4,5-Trichlorotropone takesplaceat room temperature.
"'X"' "",.'oy\zo"".
oy'\
+
|
,Fcl
\-( ct'
cl
56%
tM.
Methylaluminum bis(2,6-di-r-boty 15,204:16,209-212; 17,184-l8t Homologationof carbonyl cosT mote reactionof aldehydesr and I ketones. Isomerization of trisubstitutca . titudesis revealedin the rearrangen ohenoxide.
/)
.o'rX Ph/'Ph
V
G . B a n w e l l a n d J . H . K n i g h t , A J C 4 6 , 1 8 6 1( 1 9 9 3 ) '
SbFs/PhMe-THF -78o
an \-.\zN
/-\
Br{r />O-)2Altr,o ag' \_z )CHzCh / \
TO,
l -
.Y\ KMnOI
5,
!-
Methytamine-potassium Permanganate' Amination of nitroisoquinolines.'
NOc
02'
\ " "
.*"d3
NHMe
26"/o
lM. Wozniak and K. Nowak, LA 355(1994\.
Methylaluminum 1,1''bi(2,2"naphthoxide)' ketenewith aldehydes is subject to B-Lactones.t The [2+2]cycloadditionof (S). (S) asymmetricinduction
-7go -> -N
Chemoselective organolithits plane of cyclohexanonesby the bulkl the axial direction. Also for steric cyclohexanonesin which C-2 and C" Asymmetric Diels-Aldcr r.ta dienophiles (e.g., the acrylate of >p cycloaddition.
K. Maruoka,A. B. Concepcion, andH : K. Maruoka,A. B. Concepcion, andH 'K. Maruoka,N. Murase,R. Bureau.T I 'K. Maruoka,H. Imoto,andH. Yamerm 'K. Maruoka,M. Oishi.K. Shiohara. tr
Methylaluminum bis(2.6-di-r-butyl-4-X-phenoxide)237 PhM€, -78o, t h
r\ J:. Preparedusing DCC-DMAP' and Ir1i..:r. acid in CHzCl2 at room temperaio:.. .i,' not affect t-butyl estersand t-Boc
//'a,,
+
cHo
r? -\o 15"/"
(36"/.ee)
srtj:
f L 3 5 , 1 6 5 l( 1 9 9 4 ) .
'Y.
[f.
: ! ' r a t i o n w i t h tetrachlorocYcloProPene : h i , , r , , t r o p o n ei s isolated in 56VoYield. I
a
vvr'
I
-
c
tl-cl
\-{
rt
cll
Methylalu minum bis(2,6-di-t-butyl-4-X-phenox ide). 13, 203; 14, 206 -207 ; r5, 2Q4: 16, 209-212: 17, 184-188 Homologation of carbonyl cornpounds. The very bulky organoaluminums promote reaction of aldehydesr and ketones2 with diazoalkanes. Aldehydes afford ketones. Isomerization of trisubstituted epoxides.t A reversal of relative migratory aptitudes is revealed in the rearrangementinduced by SbFsand by the bulky aluminum phenoxide.
oy'\ -
T a m a i , M . S o m e y a ,J . F u k u m o t o , S . M i y a n o , J C S ( P I ) 1 5 4 9( 1 9 9 4 ) .
cl
56%
/F
o'r,X
aF.o..,X P/'Ph .
Phl'Ph
+
V SbF5/PhMe-THF-78o
O-)2AlMe
(^)r!o.",X Ph''Ph o""Y
92:8
89o/"
0:100
cH2c12
\'l:
y'-- \ t ,N
-7go -> -200
NOz
MeN\zL*r-\ .
\-rl..,'i
.,::" 60%
Chemoselective organolithium reactions.a The blocking of the equatorial plane of cyclohexanonesby the bulky Lewis acid fbrces attack by nucleophilesfrom the axial direction. Also for steric reasons dialkyl ketones are less reactive than cyclohexanonesin which C-2 and C-6 are not substituted. Asymmetric Diels-Alder reactions.s Single-sited coordination of chiral dienophiles (e.g., the acrylate of o-pantolactone)confers diastereoselectivityto the cycloaddition.
!ile t. to nn ,'t ketene with aldehydes is subject
'K. Maruoka,A. B. Concepcion,and H. Yamamoto,SL 521(1994). t K. Maruoka,A. B. Concepcion,and H. Yamamoto,JoC 59,4725(1994). rK. Maruoka,N. Murase,R. Bureau,T. Ooi, andH. Yamamoto, f 50,3663(1994). tK. Maruoka.H. Imoto. ,SL441 (1994). andH. Yamamoto, 5K. Maruoka,M. Oishi,K. Shiohara, ?50,8983(1994). andH. Yamamoto,
238 Methylenecyclopropane
Methylaluminum bis(2,6-diphenylphenoxide). 15, 205; 16, 212-213 Organometallic reaction of aldehydes.r Contrasteric functionalization of the more hindered aldehyde has been observed in a competing reaction, due to selective complexation of the less hindered substrates.
grBDPs \\-
+
6-\
_ ,lj tsorBDPS n/i'v
r K . M a r u o k aS. . S a i t o A 1 5 ,l l 8 3 ( 1 9 9 3 ) . . . B . C o n c e p c i oann, dH . Y a m a m o t o , J A C1S
iodides. 1-(N-Methylamido)-3-methylimidazolium Ketones. These imidazolium salts (1) are acyl transfer agentsthat react readily with organometallic compounds to give ketones.
O
t='1
o
*
*,J1.".ilrl*tt l r -
II
R'MgX THF -78o -> rt
R
n'
F . M . C o r d e r o ,S . C i c c h i , A . G o r i , a n d A I
!tethylenetriphenylphosphorene. Vinyltin cornpounds.t Acyhins ur agent.Accordingly,vinyltinsare accer
J . - 8 . V e r l h a c ,H . K w o n , a n d M . p e r e r r c . . l (
75-921"
(1)
'M.A.
d e l a s H e r a s ,A . M o l i n a , J . J . V a q u e r o J, . L . G . N a v i o , a n d J . A l v a r e z - B u i l l a "' / O C 5 t ' 5862 0993\.
O-Methyl benzenesulfenate. 16, 214 Alkyt phenyl sulfoxides.t The methoxysulfonium salts obtained from reaction of the sulfenateester with alkyl halides decomposein situ (elimination of MeX in analogy to the Arbusov reaction), leading to the sulfoxides.
Ilethyl N-ethyl-N-tributylstan nylcrrl Diacylcyclopropanes.t The rin req
.ommon tin enolates,which are not Vr ketones react well, and cyclizarion fi ;l clopropanes.
R'
I i l ^ , ^,\ ,w' H V
+
\ ('^'
'M. KerstenandE. Wenschuh, PSS80, 8l (1993).
Methyl chlorodif luoroacetate. Trifluoromethylarencs.''2 The substitution of aryl halides to give ArCFr by heating with CICFzCOOMe, KF, and CuI in DMF involves insertion of difluorocarbene into C-Cu bonds. 'J.-X. Duan,D.-B. Su,and Q.-Y.Chen,JFC 61,279(1993). tJ.-X. Duan,D.-B. Su,J.-P.Wu, and Q.-Y.Chen,JFC 66, 167(1994).
Methylenecyclopropane. 1,3-Dipolar cycloadditions.t The reaction of methylenecyclopropanewith nitrones generatesspirocyclic isoxazolidines that are prone to thermal rearrangement. Thus 4-piperidones can be prepared in a two-step process.
l. Shibata,Y. Mori, H. Yamasaki, A. B.h.-
V-Methylimidazole.
Reactions of rallylnickels.t As .l rrcial effects to allylation and coupling n
S. Knapp,J. Albaneze, andH. J. Schusar. .n
\lethyl a-isocyanatoacrylate. This dienophile is obtained in good :r€atmentwith NaReOa,COC|r, and rrrfl
F. Effenberger, J. Kuhlwein,and C. Baum3
Meihyl c-isocyanatoacrylate
s l, :: 16.212-213 of the rtrr.:!'ricfunctionalization dueto selective ni:.rrns reaction,
239
OTBDPS
/ { c s 1 1 5 .l l 8 3 0 9 9 3 ) .
'F.M.
ls. | ::,r.ter
Methylenetriphenylphosphorane. vinyltin compounds.t Acyltins undergo normal wittig reactions with this reagent. Accordingly, vinyltins are accessible.
o q
Cordero,S. Cicchi,A. Goti, andA. Brandi,TL35,g4g (1994').
agents that react readily
ll F
,
lJ.-B. Verf hac,H. Kwon,and M. Pereyre,JCS(pl) 1367(lgg3).
-5 92"/"
rnd J. Alvarez-Builla, ,/OC 5t,
Methyl N-ethyl-N-tributylstan nylcarbamate. Diacylcyclopropanes.t The tin reagentpromotes Michael reactions.conrrary ro common tin enolates, which are not Michael donors, those derived from a-chloroketones react well, and cyclization following the conjugate addition results in cyclopropanes.
R'
Dr-r: \alts obtained from reaction s. .:r \rtu (elimination of MeX in rl: r rJes.
o R"'t\./cl
+
{
Et Bu35n-N-COOM6
)
LiBr/ CICH2CH2CI
a2t
600
o R ' ll r
n14
I
c4^' 26-970/o
' I. rf ,:rl halides to give ArCFr by r : . , , l r e s i n s e r t i o no f d i f l u o r o c a r -
F: b ^- r1994).
with nif :rcrhrlenecyclopropane t f !"'ne to thermal rearrangement. F r , ' .e \ \ .
Shibata,Y. Mori, H. Yamasaki,A. Baba,and H. Matsuda , TL g4, 6567Og93\.
.V-Methylimidazole. Reactions of rallylnickels.t As an additive, N-methylimidazole confers beneficial effects to allylation and coupling reactions. S. Knapp,J. Albaneze, andH.J. Schugar, JOC 58,997(1993).
Methyl c-isocyanatoacrylate. This dienophile is obtained in good yields from methyl a-azidopropionate by rreatmentwith NaReOr,COCI2,and triflic acid.l F. Effenberger, J. Kuhlwein,and C. Baumgartner, LA 1069(1994).
rt
sulfoximine 240 S-Methyl-S-neomenthyl-N-tosyl
salts. S-Methylisothiocarbonohydrazide are formed sym-Tetrazines.t6-substituted 3-methylthio-1,2,4,5-tetrazines (1). is an oxidative last step The salts with the when iminium chloridesare treated aromatization.
A \_, i
+
ures{
,NHNH2 NHNH2
cl
+
N=N
EgN / EIOH
, )-^
ues{
NaNOz-HOAc
Mo2N'
fa
N_N
I
S.S. Taj andR. Soman,IA 5, l5l3 r 19
15-371" (1)
' S.C. Fields,M. H. Parker,andW R. Erickson,JOC 59' 8284( 1994)'
Methyllithium. 13, 188-189;14,2ll;15, 208 Deprotonation. For alkylation of enamino ketones at the 7-positionr and lithiation of allenes2the use of MeLi-HMPA is adequate. Debromination. Selective debromination of I,l-dibromoalkenes affords predominantly (98:2) the (E)-isomers.3gez-Dibromocyclopropanes are debrominated. A preparation of 1-trialkylsilylcyclopropenes by this method takes advantage of a 1.2-siliconshift.a
euy\e' Me3Si
Br
MsLi / Et2O rt,th
Methyl 2-pyridinesulfinate. Preparedin557o yield from 2-p1rr m e n tw i t h N B S i n o n e p o r t i o n . l a,B-Unsaturated ketoncs.t Th
the sulfinylation-dehydrosulfinylar using this reagentand withour the rrc requiresreflux in THF. Ketonescontaining dithioaceralg tional oxidative methods are incon thermal decompositionof the o-sul membered)is recommended.
A BuAsiM".
o
lot
ll
42"/" Reaction with carbonyl compounds. Methyl 2,3-epoxypropanoate derived from serine gives ketones on reaction with RLi or RMgX at low temperatures.It is important that MerSiCl is added before RM.5 The addition of organometallic reagentsto a-nitroketones constitutes a straightforward route to 0-nitro alcohols.o rG. Bartoli,M. Bosco,C. Cimarelli,R. Dalpozzo, G. De Munno,andG. Palmieri,TA 4, 165l
7l
RMn' B. M. Trost and J. R. Parquette, JOC g'.
5-Methyl-1,5-tetramethylene-4-p Facially selectiveDiels-Aldcr r philesgivesadductswith which srer
(1993). 2P.Audin,G. Drut-Grevoz, andJ. Paris,SC23, ll39 (1993). 3D. Grandjean andP. Pale,fL 34, ll55 (1993). nM. S. Baird,C. M. Dale,andJ.R. Al Dulayymi,JCS(Pl)1373(1993)' 5L. Pegorier, S 1403(1994). Y. Petit,A. Mambu,andM. Larcheveque' uR. Ballini,G. Barroli,P.V.Gariboldi,E. Marcantoni, andM. Petrini,Joc 58,3368(1993).
r< I
Ptr
x.alt x4 l
S-Methyl-S-neomenthyl-N-tosyl sulfoxim ine. chiral epoxides.t The carbanion derived from the sulfoximine (1) reacts with aldehydesby methylene transfer.
M. Beckmann,
T. Meyer, F. Schulz. aod
241 5-Methyl-1,5-tetramethylene-4-phenylcyclopentadiene
N o'A,\-'l l l l
A t l
lr, ' . .1.-1.5-tetrazinesare formed [. I The last stePis an oxidative
N-".'^ ".di- " : o
(1)
N=N
a.'-
'S. S. Tai and R. Soman,TA 5, l5l3 (1994).
N-N
r-:r:
15-37"/"
!9 .:\1 ( 1994).
r \c:,,nes at the 7-positionr and lithiqu.!l!' affords pre-
oi l.l-dibromoalkenes sn.';r clopropanes are debrominated' r lhr. method takes advantage of a
Methyl 2-pyridinesulfinate. Prepared in 55Voyield from 2-pyridinethiol in l: I MeOH-CH2CI2 at 0"C by treatm e n tw i t h N B S i n o n e p o r t i o n . r u,p-Unsaturated ketones.' The direct dehydrogenationof ketones involving the sulfinylation-dehydrosulfinylation sequence is achieved in a one-pot reaction using this reagentand without the need ofa sulfenic acid trap. Sulfinylation ofesters requires reflux in THF. Ketones containing dithioacetal groups can be dehydrogenated,whereas conventional oxidative methods are incompatible. Addition of CuSOq (2 equiv.) before thermal decomposition of the a-sulfinylated mesocyclic k€tones (7-, 8-, and 12membered) is recommended.
/'\
A
i
KH / THF
R/u
a2"/" lc::rl 1.3-epoxypropanoatederived i ,': R\lgX at low temperatures'It is o-:rrrtrketonesconstitutesa straighti []. \tunno, and G. Palmieri' TA 4' 165l P
I
R'
t. I i:,'nr the sulfoximine (l) reacts with
|
o
tl
*lg*, lroo
B. M. Trost and J. R. Parquette, JOC 58, 1579 (1993)
5- Methyl-1,5-tetramethylene-4-phenylcyclopentadiene. Facially selective Diels-Alder rcactions.t The reaction with various dienophiles gives adducts with which stereochemicalmanipulation is greatly simplified.
o
'vi1
: _ \t . i . r 7 3( 1 9 9 3 ) . q - : . 1 1 0 3( 1 9 9 4 ) . 'n .:J \{. Petrini'JOC 58' 3368(1993)'
l
\"Ar-Ot,te
BrAsiM".
r95:51
BocNH
BocNH OH
\ / ..t--1,
B2CuLi
-.LCHO .j
BocNH OH
*\
. / ..-i
49-93% (89-98:11-2)
Other additions. 4-Substituted dihydropyridines are usually synthesized by addition reactions on activated pyridines. Derivatization of 3-pyridinecarbaldehyde into a C2-slmmetrical imidazolidine enables the addition enantioselectiver? by using soft nucleophiles, the attack of which is preceded by coordination to the chiral auxiliary.
ilzK' \-/ dn
, ,Ph N-l
i _
pyridine-CH2C12
_cl
n
02llw ,CuCl2
tl
pyridinacH2C12
n\^ox
__-.aO
li:r'. rrf amides and estersun-
t'('
tl /\
O2llN, CuCl2
-/\
cleavage of alkenes.2 The reaction is sensitized by p-dimethoxybenzene. Ene reactions. Enones with an a-trialkylsilyl3 or a-trialkylstannyl substituent4 are accessiblefrom alkenylsilanes and stannanes,respectively,by reaction with singlet oxygen and subsequentdehydration. Instead ofdehydration, the addition
270 Ozone of titanium(IV) isopropoxide to the allylic hydroperoxide intermediates induces epoxidation of the transposed alkene linkage.5'6The hydroperoxides can also be reduced and used for other syntheticpurposes.t
SiMe3 l'9
SiMeq
A I
O2lhv,rPP
(iP'otr{H,d
-
Y
v
OH 65%(dr93:7)
TPP : tetraphenylporphyrin
Allylstannanesare convertedto hydroperoxideswith a vinylic stannylgroup.sThe reaction is stereoselective. The reaction is regio- and diastereoselectivefor allylic alcohols.'The effect of a neighboringcarboxyl group is also interesting.r0
Ph'l\^
# tAJ
1
Methyl esterc by degradation ol aILr stituted alkenes in methanolic NaOH afl Selective oxidation, 5-Hydropcro: acetals, undergo selective cleavagear rb themselvesare available from ene re*rr
MoOOC(CH2)7...
crH',..,..V
r
r€r
l o-o(\ 'o'
)-\Z\r
Pd(OAc)2*HCOONa BuaNCl-iP12NEt oMA,
800
70"/" (E:Z 56:641 Secondary reactions sometimes also take place. Thus the arylation of 4-koHetalkenyl)-B-lactamsis accompaniedby ring openingto give the 3-alkenamides'r2 substrates. from functionalized are formed carbocycles15 and erocycles'3'ra
\z\,
+
,l' Ph
Boc I
..N FCOOM€ HO
o
Ph
ftcno
Allylic oxidation. Allylic alcoho DMF.24Allylic esters are obtained fn nent with Pd(OAc)z-benzoquinonc an Someunsaturatedcarboxylic acids uod .ridative cyclization leadsto bicyclrcI
Pd(OAc)z-AcONa BuaNCl-DMF 1000
o-J I
\./Xll
zFPh Ph
1,4-Difunctionalization of 1,3- Jit
847o
Interestingly, 4-bromo-N-tosylindole reacts with ethyl acrylate in HOAc in the presenceof Pd(OAc)zat C-3 only.16 Suzuki, Srille, and related couplings, The oxidative addition of the C-B bond in aryl and alkenyl boronic acids to Pd(0) initiates the coupling with aryl halides or
rf-al 0H \4
Pd(OAch
CNblrr THF
Palladium(II)acetate275 16,259-263:
l::-ll7r
mcrhod of couPling unsaturated lu5.rratestructures,additives,and llr lr'.r: of styrenecarboxylicacids . . . : . i n t h e H e c k r e a c t i o ni s s u c cl :hc efficiencY(and in fact it was It is also he: rr pes of substrates).3 out is carried ri z,,rrzation,awhich lrc e.j in rhis reaction,a great variety 4.5ilc..1J-rtyryl-2-azetidinones.s ' alhomoallylic n.
coon"
q)
9:
O""''"oot"
ts:
isomert' g,' . hc-mo-and regioselective
,.9
on'\rt\4\ '' il
Palladium(II) acetate-tin(II) acetate. Side chain benzoyloxylationof aryl methyl ethers.t Activation of the C-H bond is achievedin the presenceof oxygenand Bzzo, giving excellentyields of the benzoates.
Pd(OAc)2
PhOMe +
on'^V'^\4n . , 6 It
o
rT. Mandai, J. Tsuji, Y. Tsujiguchi, and S. Saito, ,IACS 115,5865 (1993). I T . M a n d a i , Y . T s u j i g u c h i ,S . M a t s u o k a ,a n d J . T s u j i , T L 3 4 , 7 6 1 5 ( l g g 3 \ . -'K. Nozaki, N. Sato, and H. Takaya, JOC 59,2679 (1994). t'C. S. Cho, K. Tanabe, and S. Uemura, TL 35, lZ']/5(lgg4). IJ. P . G e n e t , E . B l a r t , M . S a v i g n a c ,S . L e m e u n e ,a n d J . - M . p a r i s , I Z 3 4 , 4 l g 9 ( 1 9 9 3 ) . ::S. L e m a i r e - A u d o i r e , M . S a v i g n a c ,E . B l a r t , G . p o u r c e l o t , a n d J . p . G e n e t , T L 3 5 , g 7 g 3 (t994). 'oD. M . X . D o n n e l l y , J . - P . F i n e t , a n d B . A . R a t t i g a n ,J C S ( p l ) l j 2 g ( t g g 3 \ . t'V. C a l o , V . F i a n d a n e s eA , . Nacci, and A. Scilimati,TLg6, l7l (1995). " B . M . T r o s r a n d C . M . M a r r s , " / A C Sl l 5 , 6 6 3 6 ( 1 9 9 3 ) . )J.-E. Backvalt,R. Gaui, and H. E. Schink, S 343 (1993). ''S. K u l a s e g a r a ma n d R . J . K u l a w i e c , J O C 5 9 , 7 1 9 5 ( 1 9 9 4 ) .
Bz2O
',6
Sn(OAc)2-O2
PhOCH2OBz
1300, 120 h
OC-/o
T. Ohishi,J. Yamada,Y. Inui, T. Sakaguchi,and M. yamashita,JOC 59,'t521(lgg4).
o
; < ' : \ 1 -1 8 9( 1 9 9 4 ) ' l: :-r1 (1993).
Palladium(II) 6cetate-tin(II) chloride. Dimethylallylation of aldehydes.t Allyltin reagentsare formed in situ from isoprene, which then add to aldehydesto afford homoallylic alcohols.
q:
-;r- r1993). ,. y; .r5alll (1994). E\
\um, C Tu, and W' Leong,JOC CL
OH I
Pd(OAc)2-SnCl2
+
RCHO
HOAC-H20 400, 24h
-
A
'R
17 - 85% I Vl. .re. SL l9l (1994)'
: s t r - 1 5 2( 1 9 9 3 ) . t - r 5 1 : 8 7( 1 9 9 4 ) . Hc:: IOC 59,4172(1994)' 6r
e9J).
a-: S Saito, TL35,5697 (1994)'
'Y. Masuyama, M. Tsunoda, andY. Kurusu,CC l45l (1993).
Palladium(II) acetylacetonate-tributylphosphine. 17, 269 Eliminations. Allylic esters undergo reductive elimination. Myrtenyl formate gives 82Voyield of a mixture of a-pinene and B-pinener in a ratio of 2 : 98. However, propargylic formate is defunctionalized without isomerization.2
,
monoxide chloride-csrbon 282 Palladium(II)chloride-copper(II) It should be Thedisplacedformateanionisthehydridesourceforthereduction. In refluxing noted that HCOONH4 is addedto the reaction of propargylic carbonates. reduced'3 is also bond benzene the triple BnO\
l
Pd(acac)2-Bu3P
BnO--
97o/"
Pd(acac)2-8u3P
BnOI HO
PhH, 800
Vnnu"
Pez{./ NSAG-.q
co rl
tCsHr
HO/'J
,CsHrr
t z
o^{' )-6 o
2
aYz'^
CsHrr
I S. F. Vasilevsky, B. A. Trofimov, A . G. \lel'l tT.T. Zung,L.G. Bruk, andO.N. Temkrn..y rY. Kondo, F. Shiga,N. Murata, T. Sakamcx 'R. D. Walkup and M. D. Mosher,f 49. 9:t5 tM. K i m u r a , N . S a e k i ,S . U c h i d a . H . H a r a r e m 76n /L993).
760/o
Elimination of unactivated sulfones to give alkenesais mediated by Pd(acac)z' rT. Mandai,T. Matsumoto, andJ. Tsuji,SL ll3 (1993)' 2T. Mandai,T. Marsumoto,Y. Tsujiguchi,S. Matsuoka,and J. Tsuji,JOMC 473'343 (1994)' ,s._K. Kang,D.-C.park,D.-G.Cho,J.-U.Chung,andK.-Y. lung,JCS(PI)23'l (1994). oY. Gai, L. Jin, M. Julia,andJ.-N.Verpeaux, CC 1625(1993)' Palladium(II) chloride. 13' 234-235; 15,245-249; 16' 268-269 done using Pdcl2 Redox processes. Hydrodehalogenationof organic halides is hand' benzils are other the On catalyst.r as anchored on poly(N-vinyl-2-pyrrolidone) DMSO' and PdClz of presence obtained2from diarylacetylenes in the compoundsa in Biphenyls. Aryl halides can couple with aryltin3 and silicon of 4-bromocarbonylation from uqu.ou, media. The acylpalladium speciesobtained biphenyl can be rntercepted in situ by 2,6-di-t-butylphenoxides'5 coupling reactions Heck-type reaction. Aryl and vinylic mercurials undergo Ring oPening LiCl' and CuClz' with p-alkenyl-B-lactams6 in the presenceof PdClz'
Palladium(II) chloride-copper(I/ll r cl Oxid.ation. The system is besr kr ketones (Wacker oxidation). It has becn c
glycosidesdirectlyr or after phorolysisof droisobenzofuranis oxidized to phthalrd An electrochemicalversion{of ttr lt tris(4-bromophenyl)amine as mediator rnr
' H. B. MereyalaandS. Guntha,TL 34.6929t tJ. Ltining,U. Miiller,N. Debski,andP. \letrr 'M. Miyamoto,Y. Minami, Y. Ukaji, H. Kroo 'T. Inokuchi,L. Ping,F. Hamaue,M. lza*e. r
Palladium(II) iodide. p-Lactones.t Vicinal cis-dicarbonl served in the presenceof PdI2 and Kl urd
with double bond migration occurs during the reaction' 'Y. Zhang,S. Liao,andY' Xu, fL 35,4599(1994)' 'f .-w. Ctri, M. S. Yosubov,and V. D. Filimonov,SC24' 2119(1994)' r A. I. Roshchin, TL 36' 125(1995)' N. A. Bumagin,andI' P' Beletskaya' 4A. I. Roshchin, DC 334'602 (1994)' N. A. Bumagin,andI' P' Beletskaya' tY. Kubota,T. Hanaoka'K' Takeuchi,andY' Sugi'CC 1553(1994)' 6R.C. LarockandS. Ding,JOC SE,208l(1993)' e' 13' 235 -236 chloride - copper(Il) chloride carbon monoxid for This combination of reagents is commonly used carbonylatioiesters' methyl the obtained as homologation of alkynes.r,2The products are usually when a proper functional group is formation bond C-C attends ff"i..o."y.firutiont-5 present at a short distance.
Palladium(II) oxidative
/"^
co/taor f f 6 h
B . G a b r i e l e ,M . C o s t a , G . S a l e r n o ,a n d G . P (
tR)-Pantolactone.16, 269-270 a-Heterosubstitutedesters. Chiral 1 of tfl reactionswith racemica-haloesters give predominantllpn ular displacements
(R)-Pantolactone 2E3
ar it. I ior the reduction. It should be trer lic carbonates.In refluxing
N'-
COOMe
.Y, VttHtrrt"
PdCl2-CuCl2 NaOAc-KzCO3
Z\r-( I
ll
Ms 76"h
,CsH't'
*on/ N,. I
*.rAz\ "
l CsHl
>-Ph
\-,/-N'
CO/ MoOH
S.F. Vasilevsky, B. A. Trofimov,A. G. Mal'kina,andL. Brandsma, SC 24,85 (1994). 'T.T. Zung,L. G. Bruk, andO. N. Temkin,MC 2 (1994). Y. Kondo,F. Shiga,N. Murata,T. Sakamoto, andH. Yamanaka, (1994). I50, 11803 'R. D. Walkupand M. D. Mosher,T 49,9285(lgg3). 'M. Kimura,N. Saeki,S. Uchida,H. Harayama, S. Tanaka,K. Fugami,andY. Tamaru,IL 34, 76ll (r993).
76"/"
r.'
rr mediated bY Pd(acac)2.
n1 J Tsuji, JOMC 473'343 (1994)' - \ J u n g ,J C S ( P I ) 2 1 7 ( 1 9 9 4 ) ' 9{:
). 16.268-269 rnrc halidesis done using PdCl2 . On the other hand, benzils are PdCl; and DMSO. trn' and silicon comPounds4in I fr,)m carbonylation of 4-bromolphenorides.5 rrrl. undergo couPling reactions r.CuCl;,and LiCl' Ring oPening
Palladium(II) chloride-copper(I/II) chloride-oxygen. Oxidation. The system is best known for oxidation of l-alkenes to methyl ketones (Wacker oxidation). It has been employed to remove the allyl group of allyl glycosidesdirectly' or after photolysis of the products.2In the presenceof CO dihydroisobenzofuran is oxidized to phthalide in 86Voyield.3 An electrochemical versiona of the Wacker oxidation in an undivided cell uses tris(4-bromophenyl)amine as mediator insteadof a Cu salt. ' H. B. Mereyalaand S. Guntha,TL 34, 6929(tgg3'). tJ. Liining,U. Miilfer,N. Debski,andP. Welzel,TL34,58'1t(t993). 'M. Miyamoto,Y. Minami,Y. Ukaji, H. Kinoshita,andK. Inomata,CL ll4g (lgg4). 'T. Inokuchi,L. Ping,F. Hamaue;M. Izawa,andS. Torii, CL l2l (lgg4\.
Palladium(II) iodide. B-Lactones.' Vicinal cis-dicarbonylation of tertiary propargyl alcohols is observedin the presenceof PdI2 and KI under CO.
hrn \ . 2
Pdt2-Kl ll lq ,1994). . -16 1:5 (1995).
^.^
X
8 0 0 , 6h
: ,r-11602 (1994). !:r 1994).
lo iI o
54o/.
'B.
-236 rbon monoxide. 13' 235 Df reagentsis commonlY used for llr .rbtained as the methyl esters' rhen a proper functional grouP is
CO / MeOH
F\ Meooc
G a b r i e l e ,M . C o s t a , G . S a l e r n o .a n d G . P . C h i u s o l i . C C 1 4 2 9 0 9 9 4 \ .
(R)-Pantolactone.16. 269-270 a-Heterosubstitutedesters. Chiral productsare obtainedfrom displacement reactionswith racemica-haloesters of (R)-pantolactone. Both inter- and intramolecular displacementsgive predomlnantlyproductswith the (S)-configuration,tdue to
acid 2E4 Pentafluorobenzeneseleninic 1,4-asymmetric induction. It has been shown that the slow-reacting haloesterprefers epimerization to direct reaction with the nucleophile.2
qF5sdG Pl*t
I
D. H. R. BartonandT.-L. Wang,IL 35. 51.t9, I 6 0 0 / .( S : F l1 0 : 1 )
'K. Koh andT. Durst,JOC 59,4683(1994)' tK. Koh, R. N. Ben,andT. Durst,TL34,4473(1993).
Paraformaldehyde. Cleavage of oxime cthers,t The generationof carbonyl compounds in the presence of Amberlyst l5 in aqueousacetoneproceeds at room temperature' Synthesisof 5,6-dihydro-4 H-1,3-oxazines.2 Acid-catalyzed depolymerization and condensationof the resulting formaldehyde with an amide gives the acyliminium ion, which is capable of undergoing a formal Diels-Alder reaction with alkenes. Bromomethylation of arenes.' The introduction of up to three bromomethyl groups is achievablethrough varying the stoichiometry of paraformaldehydeand the reaction conditions. Homologation of carbon chains. By a Grignard reaction with formaldehyde an organic halide is converted to the homologous alcohol. A preparation of the useful building block, 2-trimethylsilylacrolein,a is an example. N-Halomethyl carboxamides. chloromethylation of amides is accomplished in one step under anhydrous conditions by heating with (HCHO), and MelSiCl in THF. These products are valuable synthetic intermediates;for example, they are converted to N-acyloxymethyl amides by reaction with sodium carboxylates.sA convenienr preparation of N-bromomethyl imides is by warming the parent imides with (HCHO),, HBr, and HOAc at 70-80"C for several hours.o 'T. Sakamoto andY. Kikugawa,S 563 (1993). 2A. R. Katritzky, I.V. Shcherbakova, R. D. Tack,and X.-Q' Dai, T 49' 3907(1993)tA.W. uan der Madeand R. H. van der Made,JOC 58' 1262(1993\. nR.P. Hsung,SC24, l8l (1994). 5R. Moreira,E. Mendes,T. Calheiros,M.J. Bacelo,and J. Iley, TL35,"ll07 (1994)' 6R.C. Desai,R. P. Farrell,G.-H. Kuo,and D. J. Hlasta,SL 933(1994).
Pentaf luorobenzeneseleninic acid. Allylic oxidation.t This novel oxidizing agent is prepared from CoFo and NaSeH followed by exposing the product to Oz, Or, and HzO in sequence.It converts alkenes to enones,besidesoxidizing alcohols to carbonyl compounds'
.\, N, 1,2,4 -Pentamethyl-1r4-dihydron icotfu Enantioselective reduction' This cor keto esters and imino esters in the presctrc have an (R) configuration. J. P.Versleijen, M. S. Sanders-Hoven, S.A. \aai T 49,7793(1993).
Perf luorodialkyloxaziridines. The reagentsare available in two stepsfft SbF5[to obtain RtN:g(F)R1'] and rhen s rrl Oxyf u n ction alizat ion of hyd rocarfui tertiary C-H bonds by these neutral ard sr ceedssmoothlv.
,q.tr|-\CrFg
F
Oxidation of sulfides and su[oxidct.: perature. For example, benzenesulfenvlnnl t96%oyield) at -40'C, but further oxidarbo
D. D. DesMarteau, A. Donadelli, B. Monrenen! (1 9 9 3 ) . : D. D. DesMarteau, V. A. Petrov,B. Monranen.I (t994).
Periodic acid. 13, 238-239;16,292 Acetonide hydrolysis-cleavagc. Tern lyzed and cleaved with H5IO6.Sometirnes.e
Periodic acid 2E5
ih.rt lhe slow-reactinghaloester prefers n P h Ii e . :
PhH,
'D. H. R. BartonandT.-L. Wang,TL 60% (SiP 10:1)
tai
presi.r , r iarbonyl compounds in the ac,'. Jf room temPeralure' {cid-catalyzeddepolymerization n. s u:th an amide givesthe acyliminium )lcl. - Alder reactionwith alkenes' crju;rton of up to three bromomethyl hr,,netry of paraformaldehydeand the
#'
C6F5Se(O)OH
\.,/
^
35,5149(1994).
N,N, I, 2,4-P entamethyl-1,4-dihyd ronicotinamide. Enantioselective reduction' This compound mimics NADH and reduces aketo esters and imino esters in the presenceof Mg(ClOc)2.The hydroxyl products have an (R) configuration. rJ.P. Versleijen, M. S. Sanders-Hoven, J.A. Vekemans, S.A. Vanhommerig, andE. M. Meijer, T 49,' 1793(t993).
Perf luorodialkyloxaziridines. The reagentsare availablein two stepsfrom commercial (RJrN on treatment with SbFs[to obtain RN:C(F)Rr'] and then with ArCOrH.' Oxyfunctionalization of hydrocarbons.' The insertion of an oxygen atom in tertiary C-H bonds by these neutral and stable reagents at room temperature proceeds smoothly.
an irrgnardreactionwith formaldehyde useful the s .rlcohol. A preparation of r crample. erhrlation of amides is accomplished ratrng with (HCHO), and MelSiCl in for example'they are conIrermediates; n *rth sodium carboxylates'5A conver. hr warming the parent imides with rcrr i hours'o f n,: \ -Q. Dai,T 49'3907(1993)' :5r. ll62 (1993). n : r J J l l e Y ' T L3 5 , 7 1 0 7( 1 9 9 4 ) ' { . r . : r . S L9 3 3( 1 9 9 4 ) '
.rns agent is prepared from C6F6 and D;. (),. and HzO in sequence'It converts s r, earbonYlcomPounds'
OH
.-+-
f* re
R -'c'r'
l'1-r ClFs
f-+oH
I
re
Oxidation of sulfides and sulfoxides.2 The oxidation can be controlled by temperature. For example, benzenesulfenylmethyl azide is converted to the sulfoxide {96Voyield) at -40'C, but further oxidation at -20"C gives the sulfone (93Voyield). D. D. DesMarteau, A. Donadelli, B. Montanari,V. A. Petrov,andG. Resnati, JACS115,4897 r 1993). : D. D. DesMarteau,V. A. Petrov,B. Montanari,M. Pregnolato,and Resnati, G. JOC 59,2762 ( 1994).
Periodic acid. 13. 238-239:16.292 Acetonide hydrolysis-cleavage. Terminal acetonides are selectively hydrolyzed and cleaved with H5IO6.Sometimes, a one-pot reaction can be accomplished.'
286 Phase-transfercatalYsts HO".^.rO.,rs"\ -
-t- > I
-{) \
X
lo"ot
Potassium fluoride. 13, 256-257 ; 15, 272 As base. In the absenceof solvent KF promotes the condensationof trimethylsilylacetonitrilewith aldehydesto give the B-cyanohydrinsilyl ethers.rWith microwave as energy sourcethe reaction is complete within minutes. KF in the presenceof l8-crown-6 successfully effects the Michael reaction2between a-acetamidomalonic esters and propynoic esters also. An interesting olefination of electron-deficient ketonesr by alkanesulfonyl halides using KF probably involves sulfene formation. The removal of the fluorenylmethoxycarbonyl (Fmoc) groupo-ufrom amino acids and peptides with KF/18-crown-6 does not affect methyl, ethyl, l-butyl, benzyl, andP-methoxybenzyl groups. Actually transcarbamoylation(into Boc and Cbz groups) can be accomplishedin one flask' by presenting the proper electrophiles in the reaction mixture.5
88"/"
oroc.r'clopropanes.8This chemoseleca:..:,,n.which is presentwhen l-BuOK is
(1994). n I 50. ,1529 i.- ; lcSt Pl ) 22t7 (1994). I
1::^ 1993). Qri
O ll Ph-
+ .CFE
K CHISOTCI
F 18{rown-6 : DMF. 1100
Ph
cFo
92% As nucleophile. An enantioselectivesynthesis of a-fluoro estersTfrom the correaction using KF in responding sulfonates is based on an essentially pure .S1v2 HCONH2. The replacementof activated aromatic nitro groups requires more vigorous conditions (DMSO. 130"C).t
29E Potassiumhexamethyldisilazide The silaphilicity synthesis
from
chloromethylsilanes.
ion has been used to advantage in the B-lactam and in the rearrangement of
of the fluoride
:
ketene acetals and imines,e
silyl
9 ?TBS
ro
rR. L a t o u c h e ,F . T e x i e r - B o u l l e t ,a n d J . H a m e l i n , B S C F 5 3 5 ( 1 9 9 3 ) . 'V. T o l m a n a n d P . S e d m e r a ,C C C C 5 8 , 1 4 3 0 ( 1 9 9 3 ) . tB. S . N a d e r ,J . A . C o r d o v a , K . E . R e e s e ,a n d C . L . P o w e l l , J O C 5 9 , 2 8 9 8 ( 1 9 9 4 ) . oJ. J i a n g , W - R . L i , a n d M . M . J o u l l i e , S C 2 4 , 1 8 7( 1 9 9 4 ) . 'W.-R. L i , J . J i a n g ,a n d M . M . J o u l l i e , T L 3 4 , l 4 l 3 ( 1 9 9 3 ) . uw.-R. L i , J . J i a n g ,a n d M . M . J o u l l i e , S Z 3 6 2 ( 1 9 9 3 ) . tE. F r i t t - L a n g h a l s ,T A 5 , 9 8 1 ( 1 9 9 4 ) . oA. J . B e a u m o n t ,J . H . C l a r k , a n d N . A . B o e c h a t ,J F C 6 3 , 2 5 ( 1 9 9 3 ) . eF. T e x i e r - B o u l l e t ,R . L a t o u c h e ,a n d J . H a m e l i n , T L 3 4 , 2 1 2 3 ( 1 9 9 3 ) . 'nJ. J. Eisch and C. S. Chiu, llC 5,265 (1994\.
Potassium fluoride-alumina. 16, 282 As base. Numerous reactionsthat are initiated by deprotonationhave been conducted with KF-AI2O3. These include the synthesisof diaryl ethers, amines, and sulfides by nucleophilic aromatic substitutions,' N-alkylation of 2,4-dinitrophenylhydrazones,2condensationof 3-phenylisoxazol-5-onewith aldehydes,3and ring cloand 1,3-oxazines.a sure of N-(ro-chloroalkyl)carboxamidesto afford 1,3-oxazolines A sequenceof Michael addition, iodination, and intramolecular alkylation is inesterssfrom volved in the formation of 2-substitutedcyclopropane-1,1-diphosphonate tetraethyl methylenediphosphonate.The reagentsare KF-Al2O3 and I2.
tl
Al203.KF
(ErO)2P\
/\
(EtO)rP ' ' - t l
+
\
ll
ot l
(ErO),P -\Z
ll
-H
12,THF, rl, 15 h
/\
(Eto)2P \_ i
l
H
5s"/.(R=cN)
'E. A . S c h m i t t l i n g a n d J . S . S a w y e r ,J O C 5 8 , 3 2 2 9 ( 1 9 9 3 ) . 2 K. Thangaraj and L. R. Morgan, SC 24,2063 (1994). rD. V i l l e m i n , B . M a r t i n , a n d B . G a r r i g u e s ,S C 2 3 , 2 2 5 1 ( 1 9 9 3 ) . 4M. A . M i t c h e l l a n d B . C . B e n i c e w i c z ,S 6 7 5 ( 1 9 9 4 ) . sD. V i l l e m i n , F . T h i b a u l t - S t a r z y k , a n d M . H a c h e m i , S C 2 4 , 1 4 2 5( 1 9 9 4 ) .
Potassiumhexamethyldisilazide.13, 257; 16, 282-283 the reaccondensation Usingchiral phosphonoacetates, Emmons-Wadsworth ketones2 leadsmainly to one type of product. tion with mesoaldehydesrand
. "\AA" : :
O
O
rueolai!\o.
f
Ph
Y
++" 4hI
\-coo
Cyclopropylation.s Introduction of e ketone in one operation is not easy. Surpnr ladium complexes to give such resuhs has central carbon of the alkylating agenrsrs r
N. KannandT. Rein,JOC 58,3802(199_rr :S. E. Denmark andI. Rivera,JOC S9.6gtt rt! 'A. W i l d e ,A . R . O t t e ,a n dH . M . R . H o f f m a n
Potassium hydride. 13, 25i -258: 14. 165 Alkylation of sulfoximines.t Deproro and addition of primary alkyl bromidesrq tion. Most of the solid-liquid phase-rran range. 1,3- Shift of nonenolizable p kctorsta induced by KH-crown ether at room remF mediates. B-Cyano ketones are decompor sulfones do not react.
KH - rtoo
COOMe
T H F I r
p-Nitro ethers.3 The Michael addirroo is strongly dependenton the metal ion. Lrrh due to competing reactions. Potassiumand I
Potassiumhydride 299 ts \..n
u\ed to advantage in the p-lactam
| ::::rc..'
and in the rearrangement of
h r : . ( ' I - r - 1 (51 9 9 3 ) . l-'. C - P u e l l . J O C 5 9 , 2 8 9 8( 1 9 9 4 ) . -
:. r: ,
la
"\AA" :
i
O (Meo)2P""\o"Y KHMDS r
I
* #
I
fl
,a*l'
.
-
.
-
r
H
F
OTBS
r|
i
l
O
I
/,\
Hry\o"Y : : 4
I
Ph
87% (ratio90:10)
1 9 9 - tt . i
' ( 6 3 .l 5 ( 1 9 9 3 ) . 1 - 1 . rl .l 2 3 ( 1 9 9 3 ) .
L:
?rBb
e9-lI i
. -
: o
_J_-./-\_
JGo. &j"""".
THF. -350
\J-tooM"
/
78% (86%ee S)
t:: :.Jredbv deprotonationhavebeencon. . , 1 r h e s i so f d i a r y l e t h e r s ,a m i n e s ,a n d rr, :.. .\'-alkylationof 2,4-dinitrophenyln z . - < - o n ew i t h a l d e h y d e s ,arn d r i n g c l o r s l t , ' r J 1 . 3 - o x a z o l i n easn d 1 , 3 - o x a z i n e s . { rtr,,:. rnd intramolecularalkylation is inc l . ' r : , ' p a n el -. l - d i p h o s p h o n a tees t e r s fsr o m e i . ' i t . a r e K F - A I 2 O 3a n d 1 2 .
tl
(EtO)2R !
-*;
1 15h
,\t
83"/" (anti:syn 83 t'17) OH
, _ lt:
I
*,
l r l
D.
81%
pr.: r irom vic-dibromides,asB-chloror. .ultonesaEon treatment with Smlz. cr"\\propargyl estersby reaction with
Other reactions.. SmI2 serves as an efficient catalyst for aldol, Michael,55and Diels-Alder reactions.$The reduction of phenolss?to a mixture of cyclohexanolsand cyclohexenolsby the SmI2-KOH system at room temperature is intriguing. ' J.-L. Namy,M. Colomb, and H. B. Kagan,TL 35, 1723(1994). 2 Y. Kamochi and T. Kudo, CL l4g5 (lgg3). 3 Y. Kamochi and T. Kudo,H 36,2383(lgg3). o M. A. Sturgess andD. J. Yarberry,TL34,4'143(lgg3). 5 X. Jia, Y. Zhang, and X. Zhou,SC23, 1403(1993). " Y.Zhang, X. Jia, and X. Zhou,SC 24,1247 (1993). ? X. Jia, Y. Zhang,and X. Zhou, SC23, 387 (1993). " Y. Zhang,Y. Yu, and R. Lin, .lC 23, 189(1993). ' H.-J. Jiangand Y.-M. Zhang,HX 14,30'7(1994). 'o X. Jia, Y. Zhang,and X. Zhou,SC 24,2893(1994).
316 Samsrium(II)iodide " X. Jia, Y. Zhang, and X. Zhou, fZ 35, 8833 (1994). '' E. Vedejs and S. Lin, JOC 59,1602 (t994). ' M . H o j o , H . H a r a d a ,J . Y o s h i z a w a ,a n d A . H o s o m i , J O C S t , 6 5 4 l ( 1 9 9 3 ) . 'o P. L. Tbanez and C. Najera, fL 34,2003 (lgg3). 15 A . C h e n e d e ,E . P e r r i n , E . D . R e k a i , a n d p . S i n a y , S L 4 Z O( l g g 4 ) . '' S. Chandrasekar, J. Yu, J. R. Falck, and C. Mioskowski, ZZ 35, 5441 (1994). " J. Clayden and M. Julia, CC 2261 (1994). 't T . K a n , S . N a r a , S . I t o , F . M a t s u d a ,a n d H . S h i r a h a m a ,J O C 5 9 , 5 l l l ( 1 9 9 4 ) . re S . H a n e s s i a na n d C . G i r a r d , S t 8 6 5 f l 9 9 4 ) . tt'T. A r i m e , N . K a t o , F . K o m a d a t e ,H . S a e g u s a a, n d N . M o r i , J C C C ( T ) 4 1 , 3 3 1 5 ( 1 9 9 4 ) . t' S . F u k u z a w a a n d S . S a k a i , N i K i K5 1 3 f l 9 9 3 ) . 22 S. Takeuchi, A. Ohira, N. Miyoshi, H. Mashio, and y. Ohgo, TA S, 1763(lgg4). 2r P. de Pouilly, A. Chenede, J.-M. Mallet, and p. Sinay, BSCF 256 (1993). -' M . Y a m a s h i t a ,K . K i t a g a w a ,T . O h h a r a , Y . I i d a , A . M a s u m i , L K a w a s a k i , a n d S . O h t a , C L 6s3 ( 1993). " A . F a d e l ,r A s , 5 3 1 ( 1 9 9 4 ) . tu C. A. Molander and J. A. McKie, JOC St,7216 (1993). " G . A . M o l a n d e r a n d J . A . M c K i e , . / A C Sl l 5 , 5 8 2 1 ( 1 9 9 3 ) . " G . A . M o l a n d e r a n d S . R . S h a k y a , J O C S g , ' 3 4 4 5( 1 9 9 4 ) . t' P. Wipf and S. Venkatraman, JOC 58, 3455 0993). ""J. M . A u r r e c o e c h e aa n d A . F e r n a n d e z - A c e b e sI ,L 3 4 , 5 4 9 ( 1 g g 3 \ . to M . A . N a z a r e n oa n d R . A . R o s s i , I L 3 5 , 5 1 8 5 0 9 9 4 ) . 3r M . M u r a k a m i , T . K a w a n o , H . I t o , a n d Y . t t o , J O C S B , 1 4 5 80 9 9 3 ) . 32 M. Murakami, L Komoro, H. Ito, and y. Ito. SL 5ll fl993). 13 M. Murakami, H. Ito, and Y. Ito, JOC 58,6766 .lgg3\. t' S . H a n e s s i a na n d C . G i r a r d , S a 8 6 l ( 1 9 9 6 ) . tt E. J. Enholm and S. Jiang, H 32,224:. (lgg2). to E . J . E n h o l m , S . J i a n g ,a n d K . A b b o u d , J O C S B , 4 0 6 t ( 1 9 9 3 ) . ll H.-Y.Kang, Y.S. Cho, H.Y. Koh, and M.H. Chang, SC2t,2977 (1993). - * K a n g , S . - G . K i m , D . - C . P a r k , J . - S .L e e , W . - J . y o o , a n d C . S . p a r k , JCS(pt)9 (1993). ll S p N . M i y o s h i , S . T a k e u c h i ,a n d Y . O h g o , C L 2 l 2 g ( l g g 3 ) . o" N . M i y o s h i , S . T a k e u c h i ,a n d Y . O h g o , C L g 5 g ( t g g j ) . or M . K a w a t s u r a ,F . M a t s u d a ,a n d H . S h i r a h a m a ,J O C 5 9 , 6 9 0 0 0 9 9 4 ) . '2 J. E. Bafdwin, S.C. M. Turner, and M. G. Moloney,T 50, g4ll (1994). ot c. A. Molander and J. A. McKie, JOC 59, 3186 (1994). * J. M. Aurrecoechea and R. F.-S. Anton, JOC Sg, i,02 (lgg4). a5 R. Yanada, K. Bessho, and K. yanada, CL lli/g (1994). ou L. Crombie and L.J. Rainbow, JCS(pl) 6': 3 (lgg4.,. ot A . J . P e a r s o na n d K . L e e , J O C S g , 2 2 5 ] .( l g g 4 l . ot M . I h a r a , S . S u z u k i , T . T a n i g u c h i , y . T o k u n a g a ,a n d K . F u k u m o t o , S Z g 5 9 ( 1 9 9 4 ) . oo J. M. Aurrecoechea and M. Solay-lspizua, H 37,223 (lgg4). 5t' S . F u k u z a w a a n d T . T s u c h i m o t o ,S t 8 0 3 ( 1 9 9 3 ) . 5r C . F . S t u r i n o a n d A . G . F a l l i s , " I A C S1 1 6 , i 4 4 7 ( t g g 4 J . 52 M. Kunishima, K. Hioki, S. Tani, and A. Kato, TL35,'t253 (lgg4\. " Y . H . K i m a n d I . S . L e e , H C 3 , S O g( l g g } . 5a T . I m a m o t o , T . H a t a j i m a , a n d T . Y o s h i z a w a ,T L 3 5 , 7 E 0 5 ( 1 9 9 4 ) . tt P. Van de Weghe and J. Collin, TZ 34, 3881 (1993). tu P. Van de Weghe and J. Collin, TL35,2545 (lgg4). s7 Y. Kamochi and T. Kudo, TL 35,4t6g Ogg4l.
Samarium(III) iodide. Enone synthesis.t The Sml,_cet aldehydes(Reformatsky-type reaclionI
Cyclic ether cleavage.2 Sml, is e with acid chlorides. It also contributes er Boronate esters.3 Hydroboration r by SmL.
'Y. Yu, R. Lin, and y. Zhang,TL 34, 4S1:r 'Y. Yu, Y. Zhang,andR. Lin, SC 23, 1973I tD. A. Evans,A. R. Muci, andR. Sturrrr. . Samarium(II)
menthoxide. Aldol condensation.t Alkoxides o promoting aldolization,e.g., higher drel and (Z)-keteneacetals). Moderate enea L-menthoxideis used as catalyst. 'Y.
y. Taniguchr. Makioka,I. Nagkagawa, I
Samarium(II) triflate. Preparation.t The reagentis obrau EtMgBr at room temperature and uscd rl
Pinacol coupling.2 Comparcd r.-rr ciency has been observed.
'S. Fukuzawa, T. Tsuchimoto, andT. Kaoer 2T.Hanamoto, Y. Sugimoto, A. Sugino.eod Scandiun(III)
perchlorate. Glycosylation r a-Ribofuranosi&r and N-nucleophiles at room temperatune '1.
HachiyaandS. Kobayashi, IL 35, 3319r tt
Scandium(III) triflate. Aldol and Michael reactions.t Tbi reactions smoothly (20 examples.66_9 donors. The catalyst is recoverableand rc
Allylation.2 The highly efficienr rer tetraallyltin and carbonyl compounds rr homoallylic alcohols is promoted by Scr€
Scandium(III)triflate317 9: , / c 5 8 . 6 5 4 1( 1 9 9 3 ) .
rr:
I l\.. j:0(1994). r r 1 . f . 1 .T L 3 5 , 5 4 4 1 ( 1 9 9 4 ) . rj'i:',r. JOC 59,5lll (1994)' \ t o r i , J C C C Q ) 4 1 , 3 3 1 5( 1 9 9 4 ) '
rri \
(1994)' . i::: \ Ohgo, TA5, l'163 S : rr . ESCF256 ( 1993)' S' Ohta' CL r \ \ t a s u m i , I . K a w a s a k i ,a n d
! -uir qgl). J: a
90%
ai. ,.!ene in toluene' Selenoamidesare I irhaloalkanesin the presenceof NaH Isomerization of epoxides. a.B-Epoxy ketonesr and B'7-epoxy nitroalkanesa undergo ring opening to give a-diketones and 7-hydroxy nitroalkenes, respectively. Desilylation.5 Trimethylsilylethynyl sulfones lose the silyl group on flash silica gel chromatography. A desilylation step is thus saved if the free alkynes are the desired products; on the other hand, one must be careful about the lability of such silyl
Se
il R',^NR2R3
derivatives toward SiO2. Diels-Alder reactions of inverse electron demands.o The catalytic activity of SiOz to promote such reactions (e.g., enol ethers with a-pyrones) has been noted.
10-80%
, ; -.,lelyst for the condensation of amines ri ::.e edducts with alkyl halides gives the
J t ' t ' l t 2 3 4 1( 1 9 9 4 ) ' F \ T h e o d o r a k i s ,a n d C ' - L
Tse, 7 50' 639
(1994)' h : ' : r a n d K . S h i m a d a ,C L 2 1 0 5 I ..nu I 1994).
'..,,* been obtained for recovering carat orrJ.rrive cleavage with SeO2 in HOAc ,.
'M. Avalos.R. Babiano,P. Cintas,J. L. Jimenez, andC. Valencia,TL34,1359 J.C. Palacios, ( l 993). : M. J. Genin,P.W.Baures,andR. L. Johnson, f L 35,496'7(1994). tT. B. Raoand J. M. Rao,SC 23, 152'1(1993). rJ. Boelle,R. Schneider, P. Gerardin,and B. Loubinoux,SC23, 2563(1993)tZ.Chen andM.L. Trudell,5C24,3149(1994). uG.H. Posner, J.-C.Carry,J. K. Lee,D. S. Bull, andH. Dai, TL35, l32l (1994).
Silver bromate. Trimethylsilyl ethers are oxidized to aldehydes or acids in good oxidation.t yields by varying the reaction temperature. In refluxing CH2CI2 an aldehyde is obtained, while in refluxing MeCN the carboxylic acid is produced. rH. Firouzabadi SC24, 1065(1994). andI. Mohammadpoor-Baltork,
320 Silvernitrate Silver carbonate. a"a-Dialkoxy ketones and imines.t Heating a-bromo-a-chloro ketones or imines with silver carbonate in an alcohol effects the replacement of the halogen atoms. Carbonyl regeneration from oximes.2 Silver carbonate on bentonite is a useful reagentto convert oximes in refluxing benzene to carbonyl compounds. 'N. De Kimpe,E. Stanoeva, andM. Boeykens, S 427 (1994). 2R. Sanabria, R. Miranda,V. Lara,andF. Delgado, SC 24,2805(1994).
Silver nitrite-iodine. Dethioacetalization.t The mild r are favorable for regeneration of rh dithioacetal. The AgClOa-I2 slsrem ri sion hazard on a large-scalereacrion.
'K. Nishide, yokota, K. D. Nakamura. T S (1 9 9 3 ) .
Silver fluoride. Cyclic azomethine ylides.t Saturated a,a'-bistrimethylsilyl azacycleslose both silyl groups to form the 1,3-dipolar specieson exposureto AgF. The silver salt apparently acts both as an oxidant and a desilylating agent. In the presenceof dipolarophiles 7-azabicyclol2.2.llheptane derivatives are readily prepared from N-benzyl-
Silver(I) oxide. RCONH2 - RCN.r The dehl.drr tions employs Ag20, molecular sier,es Condensation with thiocarbo:yl with Ag2O renders such compounds rc p-Quinone methides.r 4-Alk;. lp
2,S-bistrimethylsilylpyrrolidine. A short route to epibatidinebasedon this chemistry has been developed.
stances.It is a useful way to induce crc matic ring. OH
)Y
SiMes |
\
.Nan SiMe3
+ epibatidine
X X : COOEI, CHO,CN,No2
'G.
70-83/"
Y
^@
ar-
P a n d e y ,T . D . B a g u l , a n d G . L a k s h m a i a h , T L 3 5 , 7 4 3 9 ( 1 9 9 4 ) .
Silver nitrate Allenones to furans.t The isomerization typified by the following equation can be used to prepare 3-deuteriofurans.
A9NO3
r:C=f.
czHrs
J
[cuH,. v
"ffi
/\\ C7H1549'/-C6H13
o
Butenolides from p-(1-bromoalkyl)-B-lactones.' The dehydrobromination with ring expansion works in general. The bromo-B-lactonesare the kinetic products of bromolactonization of Bry-unsaturatedacids. 'J. A. MarshallandG. S. Bartley,JOC 59,7169(1994\. 2T.H. Black and J. Huang,TL 34, l4ll (1993).
'M. L. Sznaidman, C. Crasto,andS. M. llc '1. Shibuya,Y. Taguchi,T. Tsuchiya.A Or 'S. R. Angle,D. O. Arnaiz,J. p. Boyce.R p Rainier,K. D. Turnbull, and W. yang. .tO(
Silver(Il) oxide. Etherification.t Methyl and isopn zyl bromides are heated with AgO in rh '8. Ortiz, F. Walls,F. yuste,H. Barrros ( 1993).
Silver perchlorate. 16, 300-301 Replacement of anomeric u-halq with LiClOa or PhSnS provokes rhc hcr used as nucleophile for the glycosylarro
Sllverperchlorate321
Irn: rr-bromo-a-chloro ketones or r:. :hc replacementof the halogen ir..::l',onateon bentoniteis a useful h- -.,rhonyl compounds.
.': (1994). ( :{ rtsOs
t :.: :: rlethylsilyl azacycleslose both F ...r. to AgF. The silver salt appar| ::Jnt. In the Presenceof diPolarr: :L'rdily preparedfrom N-benzYl, cr:f,.rtrdinebasedon this chemistry
Silver nitrite-iodine. Dethioacetalization,' The mild conditions (aqueousTHF at room temperature) are favorable for regeneration of the carbonyl group from a monothioacetal or dithioacetal. The Agcloa-I2 systemis even better, but it suffers from potential explosion hazard on a large-scalereaction. 'K. Nishide,K. Yokota,D. Nakamura, T. Sumiya,M. Node,M. Ueda,andK. Fuji TL34,3425 ( 1993).
Silver(I) oxide. RCONH, - fiCN.' The dehydration of primary amides under nonacidic conditions employs Ag2O, molecular sievesand EtI. Condensation with thiocarbonyl compounds.z Activation of the C:S bond with Ag2O renders such compounds reactive toward nucleophiles. p-Quinone methides.3 4-Alkylphenols are oxidized to these reactive substances.It is a useful way to induce cyclization by a weak nucleophile such as an aromatic ring.
w Y LO or-l
,cl
Ageo
+
-
epibatidine
9
,eg-l)
:d hr the following equation can
' 3'\cuH''
w Y w OH
znch
/^Y\
93V"
'M. L. Sznaidman, C. Crasro, andS.M. Hecht,TL 34, lsgl (lgg3). 'I shibuya,y. Taguchi, T. Tsuchiya, A. oishi,andE. Katoh, BCSJ62,304g (rgg4). 's' R' Angle,D.o. Arnaiz, r.p. Boyce, R.p. Fruros, M. S.Louie,H. L. Mattson-A rnaiz, J.D. Rainier, K. D. ?urnbull,andW. yang,JOCSg,63220tgg4\. Silver(Il) oxide. Etherification.t Methyr and isopropylbenzyl ethersare formed when the benzyl bromidesare heatedwith AgO in the corresponding alcohols. 'lr:r?lil, F. Wa,s,F. yuste,H. Barrios,R. Sanchez-Obregon, pineto, andL. SC 23,74g
rr.
The dehydrobromination rtr)nesare the kinetic products
Sifver perchl orate. 16,300_301 Replacementof anomeric u-haloacetoxy groups. A combinationof Agcloa with Liclor or Phsns provokesthe heterorysi, or ru.h esters.rA silyl ethercan be usedas nucleophilefor the glycosylation.2
322 Silvertriflate Glycosylation bl trityl sugars.3 Disaccharide formation catalyzed by AgcloaSnCla makes it possible to use the more stable trityl sugars(in situ detritylation) as nucleophiles. Friedel-crafts acylation.a using the AgCloa-Sicla combination as catalyst, the acylation ofarenes with free carboxylic acids and an aroic anhydride proceedsvia the mixed anhydrides. 'T. MukaiyamaandN. Shimomura, CL 7gl 0993). 'N. Shimomuraand T. Mukaiyama,BCSJ 67,2532(1994). 3S. Houdierand P.J. A. Votrero,TL 34, 3283Ogg]D. 4 K. Suzuki,H. Kitagawa,and T. Mukaiyama, BCSJ66, 3:l2g(tgg3').
s'Glycosides.2 Thioglycosides can be prepared from glycosyl bromides by reaction with B-trimethylsilylethyl sulfides in the presenceof AgBFa. The silver salt provides Ag* to assist ionization of the halogen, and also a F to initiate removal of the silylethyl group of the intermediately formed glycosylsulfonium salts. rD. Barbry,C. Faven,andA. Ajana,SC 23,2647(lgg.J). 'A. Mahadevan, C. Li, andp. L. Fuchs,SC 24,30ggllgg4\.
Silver tri f lat e. 13, 274 -27 5: 14, 282- 283; 16, 302; t7, 314 Glycosylation Anomeric trichloroacetimidates,rphenylselenides,2 and carbonatesr are substituted by oxygen and nitrogen nucleophilesin the presenceof Agorf. For the displacement of glycosyl bromides,at-butyl ethers instead of the hydroxvl compounds have also been used successfullv.
?Po" Bzo A,
f"jot'
ffi
-f^YcoocoFs
a'o$-\-o''^\-)
NHFmoc
z\
ph_t/
\
OTs
.\,_h
.
^
d
TsO
Free radicals lrom a_halokerond.r alkenesresultsin coupling products.
M. whirfierd,andJ.J Krrprr ]l l:?:rr,':._o. -s. Mehtaand B. M. pinto,.fOCSt, 3269 r t99!r 'N. Shimomura, T. Matsutanr, andT. Muhrrtr A. vargas-Berenguel, M. Meldal,H. paul*a. X Lr.crarg and V. R. N. Munsinghe, CC 9Ol I l99j Burk.T.S. Cac,andM. B. Roof.rL $. t ;I lt Derzel.S. Goulet,L. Grenier,J. Bordclcrr. r ",x. R R T y k w i n s kai n dp . J .S r a n gf ,4 9 . 3 O { 1 , ; ; s.-H. Oh andT. Sato,JOC 59,3744(1991t
Silver trifluoroacetate. 16, 301_302: 17. -rl Photochemical t r if lu oromc thyta t iot. trifluoroacetic acid with AgOCOCF_TrO; rC. Lai andT. E. Mallouk,CC 1359(t99-1r
BzO 7110
Intramolecular C-glycosylation by tanes.5
Areneselenenyl triflates, Conr.enror AgOTf makes it possibleto avoid inrrodrr strates on their selenylation. For examp readily achieved.T
Functionalized alkynes lrom alty:7 , valent iodinated acetylenes are fornrd b P h l ( C N ) X ( X : O T s .O B z , S C N ) . Etimrn on rreatment with AgOTf. The reacrion rs
Silver tetrafluoroborate. 13, 273-27 4 Aliphatic Friedel-crafts acylations.t The Ag(I)-catalyzed reaction of an acyl chloride with functionalized alkenes proceeds under mild conditions. Functional groups such as halogens,ketone, and ester can be tolerated.
BzosT\ +
Etherification,6 Various alcohols rp fied with primary alkyl halides in . rca, t-butylpyridine.
silyl enol ether leads to bicyclic acyloxe-
Sodium. 13,277 Carbonyl reductions, In an alcohol sob related compounds. 3_Anisyl-methylercctrq isoborneol,rwhich is a potential chiral aurrlr from B-enamino ketones, but there is lrt of Carboxamides are usually reduced to prr tuted amino acid amides afford the 2-emrr propanol.
sodium 323
t i : j . : \ \ r m a r r o nc a t a l y z e db y A g C l o I l : : r . . u q 3 r c( i n s i t u d e t r i t y l a t i o n a) s g( r t- 5161.combination as catalysr, d. ::j ro aroic anhydrideproceedsvia
t.'-:
) / tO :-19 r 1993)
Etherification.6
Areneserenenyr trifrates. Conversionof serenenyr bromidesto the triflates by Agorf makesitpossibreto avoid introductionof the halogenatom to the alkenesub_ For example,stereoselective serenomethoxyration ::ffi is ntti}.i""nvlation' Functionarized arkynes froT arkynyr(phenyr)iodine(Ill) esters.s The hypervalentiodinatedacetylenes are formed uy ,.u",ion of tributyrstannylalkynes with PhI(CN)x (X : ors' oBz' scN). urminution or a., ,.o,n rhese derivativesoccurs on treatmentwith AgOTf. The reactionis applicableto diyne substrates.
) '-.:,
AgOTf
Ph-l
brr
Z\
t-Ph crucf, Lo,
rsd
OTs
210/"
Free radicars from a-haroketones.s photodechrorination in the presence of alkenes results in coupling products. ' S.P. Douglas,D. M. Whitfield, andJ.J. Krepinsky,JCC 12,l3t ( 1993). pinto,
andB.M. ,l; y,.n,u
9&:
arnnhnr" /--:*^_,.
ffililfii[1._,n,1i",?JiJ,T...niilTJnil#iJ;H ru.
bc {g I r-catalyzedreactionof an acyl b ::Jer mild conditions. Functional fr r 'lerated. f,(r::i'J from glycosyl bromides b-rh. r:!'\ence of AgBFa.The silver salr t- ::J also a F- to initiate removalof :.i i. r eosvlsulfoniumsalts.
variors
loc se.:zis iii'e3il^,'
r\. rnrmomura. T. Marsutani,.and T . M u k a i y a m a , B C S J 6 7 , 3 l O O( l g g 4 ) . '.A . V a r g a s - B e r e n g u eM l, . Meldal, H. p."l;;.;.; tD. : n s e n 'a n d K ' B o c k , J C S ( P I ) Craig and V. [. N. Munsrnghe, 3 2 8 7( l g g 4 ) . CC g1l (lgg3).
_ 1:, 1 7 .3 1 4 rJ,:e.. phenylselenides,2 andcarboncic,,nhilesin the presence of AgOTf. bt;:, I erhersinsteadof the hydroxyt
.l y.."".o, r. S.Gac,andM.B.nror,.r ji, ai'il (tss4).
.R.Deizel,S.Goulet.L.Grenier,J.B..d"l";;,ini'l.S"rni"., "R. JOC58,36l9(1993). R-.Tykwinski and p. J. Stang, , i;,;;;;li;;;. " -,' 'S.-H. Oh andT. Sato,JOC Sg,37440l994\t.' Silver irifluoroacetate. t6, 301_302; 17, 313_3t4 Photochemicar trifruoromethyration.t a*n", trifluoroacetic acid with AgOCOCFTTiOz.
tuior.-
fY^YcoocoFs
a.: )!1--o'^\"2
NHFmoc
'C.
undergo trifruoromethyration
in
Lai andT. E. Mallouk,CC l35g(lgg3\.
?zo 7go
D(.i .rher leads to bicyclic acyloxe-
Sodium. 13,277 carbonyr reductions. In an alcohol solvent sodium reduces ketones,esters,and related compounds. 3-Anisyl_methyleneca;o;;; gives 3_endo_(p_methoxybenzyl)_ isoborneol,rwhich is a potentiar chiral auxiriary. 1,3-Amino alcohors are obtained2 from B-enamino ketones,but there is lack of stereoserectiuity in the reduction. carboxamides are usually^reduced ,o p.iru.y amines. However, a,a-disubsti-
illil;l'""
acid amidesafford the 2-aminoethanorsi on ."ou.,ion*ui,hNa in
324 Sodiumarenesulfinates Sodium deposited on alumina is also a convenient reducing agent.4 A nonprotonic solvent such as THF is used in the reduction.
*-Q
'8. I. Seo,L. K. Wall,H. Lee,J.W.Burtrum,andD. E. Lewis,SC23, l5 (1993). :G. Bartoli, C. Cimarelli,andG. palmieri,JCS(pl)53: (lgg4). r H. M. Moody,B. Kaptein,e. B. Broxterman,W. J. H. Boesten,andJ. Kamphu ts,TL 35, 177.1 (1994). 'S. ,igg:'. SinghandS. Dev,T 49, l0g5g
Sodium amalgam. Redactive elimination.t A method for the synthesis of conjugated dienes and trienes involves reaction of r,4-dibenzoyloxy-2-alkenes and 1,6-dibenzovl oxv-2.4alkadieneswith Na-Hg.
OTBS
OBz
:
/
,
\-,/ Y i OBz
ii
\/:
/
6reS
Na(Hs) MSOH-THF
-2e
Replacement of an unsaturatcd phc4 sulfonesby a tandemMichael addition_clrn allows the synrhesisof (Z)_1,2_bis(benzcr fonyl)alkenyliodonium salts.2In pkerocrb withdrawing power of the ketone group rs .t carbene formation. Cyclopentenones are for alkynyl(phenyl)iodoniumsalts gives alkr nr
I OTBS
\r\. '/
rcao^
\ '\ion N
TfO'G.
Solladie, G. B. Stone,J.-M.Andres,andA. Urbano , TL 34,2g35fi993).
Sodium-ammonia. 16, 303-304 3-Arylbutyraldehydes.t These aldehydes are produced when 5-aryr-4,5dihydro-1,3-dioxepins are subjected to reduction with Na-NH3. The transformation may involve elimination to furnish dienolate ions, which undergo reduction at the styrenic double bond.
ot'-forr"
\-i"'
NaaH3
:E;-
-l.-
Ar
olot 's.
Free radical addition to alkencs. Gcr the presenceof proper alkenes leads to sulfo radical can be created in a remote position. rL C. Castedo, J. Delamano, C. Lopez,M. B Lol K . o s h i m a ,y . M a s a k iM , . Kun,*,J ,Y.o:lill: n . L . w t l t t a m s o nR. . R . T y k w i n s k i , p . and J Sre r 'R. R. Tykwinski,B. L. Williamson,D. R. Frs+.J (1993). 'C.-p. Chuang,5C23,23-n(tgg3). '1.W. HarveyandG.H. Whitham, JCS(plt tt5 rt9
-cHo 49- 810/o
I K.
Ta.SOrr
(ou"
_9rBS /\/\/\/\/ 96%(>95o/.EEg
/coot|/p-
Samizuand K. Ogasaw ara,TL 35, Tggg lgg4l.
Sodium arenesulfinates. Heteroarylmethfl p-toryr surfones.t These compounds can be prepared from the corresponding benzylic alcohols by reaction with 4-Mecotlaso2Na and HCooH. The method is useful for substratespossessingo* values between -1.90 to -0.95 in the aryl ring.
Sodium azide. a-Azido amides. An unusualprepanlrq with NaNr in the presenceof l5_crown_5. o-L the other hand, the displacement of a-(4_nirrd ate q.-azido ketones2is a simple S7y2reactron
o
tl Ph'v''\N-oMs cHs
N.rr3 t$om.: CH&
!
Sodiurn azide
!rent reducingagent.4A nonprotonic
,cooMe
Ho l-\
TolS02Na
\e-'\
/'
N
E - e * r s .S C2 3 , l 5 ( 1 9 9 3 ) . t_:- :99.1). I B. t.ten. andJ. Kamphuis,TL35,177'l
I-oM"
HCOOH
325
,cooMe
rotspzf-\ ^N'
(o"" 987.
; .r nrhesisof conjugateddienesand l-a.\enes and 1,6-dibenzoyloxy-2,4-
Replacement of an unsaturated phenyriodo groap, Formation of unsaturated sulfonesby a tandemMichael addition-elimination is a highly efficient processthat alfows the synthesisof (z)-r2-bis(benzenesulfonyl)alkenes from (Z)-F-bjenzenesulfonyl)alkenyliodonium salts.2In B-ketoethynyl(phenyl)iodonium salts the electron_ withdrawing power of the ketone group is weaker, the Michaer addition is foilowed by carbene formation. Cycropentenonesare formed.3 A seemingly direct substitution of alkynyl(phenyl)iodoniumsalts gives arkynyl sulfonesefficiently.a
Jr65
:
'V:/\^Y OTBS
16.. (>95% EEq
o \r\. / /
rotso2Na
\ \ \,._.- t P h
20o,
Tto-
t n . I L 3 4 , 2 8 3 5( 1 9 9 3 ) .
r,re produced when 5-aryl-4,5o * rrh Na-NH3.The transformation on.. *hich undergoreductionat thc
cHzct2
o r ll -Y'>r'Y ll
SO2Tol
15 min
72"/"
Free radicar addition to arkenes. Generation of the toluenesulfonyl radicar in the presenceofproper alkenes leads to sulfones,s and cyclization occurs6when a free radical can be created in a remote position. I L. C. Castedo,J. Delamano,-C . Lopez,M. B. Lopez,and G. Tojo,H 3g, 4g5(lgg4). K. oshima,y. Masaki,M. Kunishima,ano r (cis: trans - 10 : 1)
ondary alcohols to carbonyl compounds, hydrazobenzenesto azobenzenes.By contrast, oxides of lower pnictogen elements are devoid of oxidizing power for organic substances. 'T. Ogawa,T. Hikasa,T. Ikegami,N. Ono,andH. Suzuki,CZ 815(1993). 2H. Suzuki,T. Ikegami, and Y. Matano,TL 35, 8lg'l (1994).
36t
Tributyltlnhydride
Tribromomethyl(trimethyl)silane. Methylketonesfrom aldehydes.t The homologation is mediatedby Cr(II). 'D.
M . H o d g s o na n d P . J . C o m i n a , S L 6 6 3 ( 1 9 9 4 ) .
Tributylstannyloxyalkenes. y-Imino ketonesand diketones.t Tin enolatesare very reactivetowarda-halo imines,forming iminoketonesthat are readilyhydrolyzed. rM.
Y a s u d a ,Y . K a t o h , I . S h i b a t a ,A . B a b a , H . M a r s u d a ,a n d N . S o n o d a ,I O C S g . 4 i E 6 . l g g 4 i t .
readily available, assembly of difunctrooi now a recognized avenue. Furthermore. r chain extensionprocess.'2.'3 Free radical cyclization of 1,6-diencs" ,
double bonds is much valued becauserbc rr orated further. Stannylformylation is olr 1 A very important tactic for c-amino n hydrogen abstractionby an aromatic frec n
away. Thus chain extension at the a-posrrr plished with great success.
Tributyltin
halides. 13, 315 Vinyltins. BurSnCl is commonly used as an electrophile to trap alithioimines,' enolatesoftrimethylsilylaceticesters,2 and alkynyltrialkylboratesalts.3 p,y-Epoxy ketones.4 The reaction of tin enolates with o-halo carbonyl compounds generally affords l,4-dicarbonyl products. However, in the presence of
,nr)
b
Bu3SnBr and BuaNBr the major pathway is switched to attack on the carbonyl group instead of on the a-carbon, resulting in Bry-epoxy ketones. 'B. Jousseaume, M. Pereyre, N. Petit,J.-B.Verlhac,andA. Ricci,JOMC443,Cl (1993). ' A. J. Zapata, C. Forroul,and R. C. Acuna,JOMC 448,69 (lgg3). t M.-2. Deng,N.-S. Li, andY.-2. Huang,JOC58, 1949( 1993). oM. Yasuda, T. Oh-hata,l. Shibata,A. Baba,andH. Matsuda,JCS(|t) 859(1993).
Tributyltin
hydride. 13, 316- 319; 14, 312-318; 15, 325 -333; 16, 343-350;
17,35r-361 Reductions. BurSnH is capable of reducing epoxidesr in the presenceof MgI2, giving alcohols. on the other hand, epoxy ketones suffer reduction at the carbonyl group.t BurSnH-SiOz is useful for reduction of aldehydes.3 Hydrodehalogenation. A synthesis of chiral epoxidesa from trichloromethyl ketones is through enantioselectivereduction to the trichloromethyl carbinols and tinhydride-mediated conversion to the chlorohydrins before base treatment to close the three-memberedring. Dehalogenationof halocarboxylic acidssin water is apparently a method that deserveswide application. other defunctionalizations. Deoxygenation of alcohols via thioxocarbamate derivativesoor benzothiazol-2-yl sulfidesT(formed by Mitsunobu reaction) is readily achieved. Isonitriles have been preparedfrom carboxylic acids via selenocarbamates.8 when a leaving group is presentat the B-position of the seleniumatom, the homolysis of the C-Se bond is followed by expulsion of the B-substituent.Glycal formatione from azidosugar selenideson treatment with Bu3SnH occurs in excellent yields. Chain extension. a-Alkoxy radicals and B-acetoxy radicals generatedfrom the selenidesr0and iodides,r'respectively, add to alkenes. Since the precursorsare quite
,
&rrsr* . ea
crlz=c{r.|coc Pt*r s
Construction of carbocyclcs. Formetr by treatment of unsaturatedthiocarbametc Bu3Sn11.te-zt When the radical adds ro a rn is formed.
Although the goal ofconstrucring rhc lyr cyclization by a tandem free radical crclrz the remarkable power of such process.s.
ueooc.-f phs-/
/ t
\
ftar
i
lrr@ N-
\Me \
r'1
l
l
V"/
Bu3SnH l
-
A" A three-component free radical reruoo, ester is also quite useful. ETOOC: ,OBu r l \ + COOMe
Brrsrt{
Tributytttnhydride 369
il, g.tron is mediatedby Cr(II).
It.. Jre very reactivetoward a-halo i . 1 : ,I r z c ' d . r :rJ \ Sonoda,JOC 59,4386(1994).
-i\ rn electrophile to trap q.I rnd alkynyltrialkylboratesalts.3 n,'lrr('\ with o-halo carbonyl com)r-r. However, in the presence of h.J r() attack on the carbonyl group r.
readily available, assembly of difunctional compounds by free radical reactions is now a recognized avenue. Furthermore, alkenyl radicals can be used to initiate the chain extensionprocess.''.13 Free radical cyclization of 1,6-dienesrawith functionalization at the termini of the doublebonds is much valued becausethe two different functional groups can be elaborated further. Stannylformylation is one possibility. A very important tactic for a-amino radical generationinvolves translocation via hydrogen abstractionby an aromatic free radical generatedfrom a halogen five bonds away. Thus chain extension at the a-position of an amide15or amine16can be accomplished with great success.
l,i ,
h\v
^TU"oo'"
Bu3SnH- AIBN CH2=C1iil.lggttt
)-
PhH, A
95o/.
l\ iL-t()nes. o; \ Ricci, JOMC 443,Cl (1993). L a" 1993). l ! , q 9 3) . t l : r . u J a .J C S ( P I )8 5 9 ( 1 9 9 3 ) .
t 5 t l 5 - 3 3 3 ; 1 6 ,3 4 3 - 3 5 0 ; | .t (\\idesr in the presenceof Mgl2, x. .uft'er reduction at the carbonyl 'r r l i c h rd e s . r r.l cpoxidesafrom trichloromethyl ) rh. trichloromethylcarbinols and lr:n. before basetreatmentto close x : r h r r r y l i c a c i d s si n w a t e ri s a p p a r rn , l alcohols via thioxocarbamate :.J i.r Mitsunobu reaction) is readily When I r. rJs via selenocarbamates.8 r\
\?-d !
F
r.
Et3N MeOH- CHrCb 0o, 5min
OH
82"/.
I ,r-ctto 85"/"
It: S .ulfoxides are reducedin verY 5 -i. reaction to sulfinylethylation of The Polonovski reaction of H:. :( ) ( ) in the presenceof a comPound lr.r.'. trifluoroethylidenationat that . :. .rctivated by (CFTCO):O toward
IM. E l G i h a n i a n d H . H e a n e y ,S L 5 8 3 ( 1 9 9 3 ) . tc.T. Crisp and A. G. Meyer,S 667 (lgg4). 'R. L . F u n k , J . U m s t e a d - D a g g e t ta, n d K . M . B r u m m o n d , T L 3 4 , 2 5 6 7 ( l g g 3 ) . nW H . P e a r s o n ,R . W a l a v a l k a r ,J . M . S c h k e r y a n t z ,W . - K . F a n g , a n d J . D . B l i c k e n s d o r f ,J A C . ! l 1 5 , 1 0 1 8 30 9 9 3 ) .
Trifluoromethanesulfonic anhydride (triflic anhydride). 13, 324 -325: 14, 324-326: 15, 339-3401 16. 357-358 Perfluoroalkynylphosphonate esters.t Phosphonylmethyl perfluoroalkyl ketones are dehydrated to give the alkynes on reaction with Tf2O and /-Pr2NEt via triflyl ethers. Isoquinolines.2 A one-step synthesis of these heterocyclic compounds requires phenylaceticesters,nitriles, and TfzO. Conjugated triflones.s Reaction of MerSiCHzl-i (from MerSiCH2I and r-Bul-i) with Tf2O and then with aldehydesgives the triflones in 56-84Va yleld.
37E (Trifluoromeihyl)trimethylsilsne 'Y. ShenandM. Qi, JCS(PI)2153(1993)' Sl andL' R' Subramanian' 'A. G. Martinez,A. H. Fernandez, D' M' Vilchez'L' L' Gutiererez' 229 (t993). t A. Mahadeuan and P.L. Fuchs,?L 35' 6025(1994)'
'G. K . S . P r a k a s h ,D . D e f f i e u x , A . K . \ ' u d r r rK. I s e k i , T . N a g a i , a n d Y . K o b a y a s h r .f L J tC. P. Felix, N. Khatimi, and A. J. Laurrnr. oT. B r i g a u d , P . D o u s s o t ,a n d C . P o r r e l l a .C (
S-(Trif luoromethyl)dibenzothiophenium trif late' Trifluoromethylationofenolates,Bulkyenolboronatesundergotrifluoro. such as the dienolatesof 8amethylation with (1) in a stereoselectivemanner in cases
Triisopropoxytitanium
methyl-A4-octal-3-one.
vising a route to 2-deoxy-o-ribose.
Regioselective PrO):TiOAc
'Y.
.q,".q, *o-eb ffi(2.5 : 1)
cFs T'o-
(1)
acetate. cleavage
of
epn
regioselectively to give -1-e
E. Raifeld, A. Nikitenko, and B. \l
An
2,4,6.Tri isopropylphenylboreD€ (trit Hydroborations.' This boranc rs
with alkenes to form either TripBHR I mixed boranesTripBRR'. Oxidation of TripBR2 with cyanide leadsto R. =O ' K. Smith,A. Pelter,andZ. Jin. JCS| PI ' 9
'T. Umemotoand K. Adachi,JOC 59' 5692(1994)'
(Trifluoromethyl)trimethylsilane'
B-(Trimethylsilyl)alkyl phenyl sulfor Vinyl anion equivalents.t Afrcr t trophiles,elimination of the sulfonllAr as electrophilethe treatmentwith r-aH transsilylationto preludeexpulsionof tl
15' 341
Preparation.' 2 e-, BulNPF6
B€F3
+
Me3SiCl
PhOMe - HMPA
Me3SiCFg 73"/"
converted into the trifluoroTrifluoromethylation.2 carbonyl compounds are presenceof a quaternary the in reagent methyl carbinols in excellent yields by this ammoniumfluoride.Moderateasymmetricinductionisobservedwhenachiralcatalyst is used. is also smooth. Addition to azirinesl giving 2-trifluoromethylaziridines is promoted by acylsilanes from The synthesis 2,2-Difluoroeroryrllonri.o *(Ph.SnF2)-. with Bu+NF the primary products undergo further aldol BuoN
-,/-\..OR
o
+
MesSi-
_:.*
R=SiPhzt-Bu
' B. Achmatowiczand J. Wicha.IA 4. ,r99,
reactions.
o
t
ll Ph
SiMe2f-Bu
Bu.N+Ph3SnF2
F,
THF, -780-> -20p,t h
F
/OSiMeat-Bu
CF3SiMe3 P
h
79/"
Trimethylsilyl azide. 13,24-25'. 11. ! Tetrazoles. Formation of tetrazolr Me,Al.t B-Glycosyt azides.3 A high-1 rcld volvesMerSiNr, SnCla,and AgClO. as r
Trinethylsilyl azide 'G.K.S. P r a k a s h , D . D e f f i e u x , A . K . y u d i n , a n d G . A . O l a h , S L l O 5 7( l g g 4 ) . 2K. Iseki, T. Nagai, and y. Kobayashi, fZ 35, 3137(lgg4). 'C. P . F e l i x , N . K h a t i m i , a n d A . J . L a u r e n t , T L 3 5 , 3 3 0 3( l g g 4 ) . oT. B r i g a u d , P . D o u s s o t ,a n d C . p o r f e l l a , C C 2 l l 7 . l g g 4 t .
, L C : r r e r e r e z ,a n d L . R . S u b r a m a n i a n S
bte. cnol boronates undergo trifluoroin ;a:es such as the dienolatesof 8a-
Triisopropoxytitanium
acetate. Regioselective cleavage o! epoxides.t 2,3-Epoxy alcohols react with (rPro)rTioAc regioselectivelyto give 3-acetoxy 1,2-diols. This result is useful for devising a route to 2-deoxy-o-ribose. ' Y. E.
--l-^..., l
t, "Y
l
*
a^J.^.. l l l
2,4,6-Triisopropylphenylborane (tripylborane, TripBH2). Hydroborations.t This borane is a stable solid that can react regioserectively with alkenes to form either TripBHR or TripBR2; TripBHR can be converted into mixed boranes TripBRR'. Oxidation of the adducts furnishes alcohols. Treatment of TripBR2 with cyanide leadsto R2C:O.
o4'€'/
CFS
CFO
(2.5 : 1)
'K.
Smith,A. pelter,andZ. hn, JCS(pt)395(1993).
B-(Trimethylsilyl)alkyl phenyl sulfones. vinyl anion equivalents.t After the derived sulfonyl anions react with electrophiles,elimination of the sulfonyl/silylgroups may be induced.with an epoxide as electrophile the treatment with NaH in refruxing hexane actually triggers a c/otranssilylationto preludeexpulsionof the sulfinate anion.
,? rl;
rJ. are converted into the trifluoropnr rn the presenceof a quaternary rrr(\n ls observedwhen a chiral cata-
--_,--^r,..-oR
+
MesSi\Asorpt
o
NaH, a
R=SiPhzl-Bu
r l . r r r r r d i n e si s a l s o s m o o t h . I lrom acylsilanesis promoted by ! products undergo further aldol
bs. '
\
> ?t* .r
F
/OSiMe2l-Bu P
h
797o
'
B . A c h m a t o w i c z a n dJ . W i c h a , Z A 4 , 3 g g
19gr.
Trimethylsilyl azide. 13, 24-25; 14, 25; 15, 342_343:16. 17 Tetrazoles. Formationof tetrazolesfrom nitriles is catalyzedby Bu2Sno, MerAl.2 B'Glycosyl azides-3 A high-yielding preparation from peracyrated sugars involves MerSiN3, SnCla,and AgClOa as reagents.
3t0
TrimethYlsilYlbromide
Pd(0)-catalyzed ionizatt:i t",itt^1t.1rr-allYlPalCleavage of allyl esters'4 The an active state' The processedto return the metal in ladium species' which must be fulfills this purpose' MerSiNrBunNF combination is catalyzed by (rThe epoxide opening by Me3SiNr F-Azido alcohols'5 BuN)zCrCl:. (1993)' I S.J. Wittenberger andB' G' Donner'JOC 58'4139 (1993)' 80ll 34' r/tS.;. H"ff anO-tU. e' Staszak' '[, plit."uutu andT' Mukaiyama' CL 247 (1994)' 'c. irt.pi- andD. Buechler'TL35'5421(199!)'-Yeung'?L 36' 107(1995)' ,w.-H. Leung,E. r. F. cnow, M.-i. W", p.w.y' furn' andL'-L' 17' 378 .. Trimethylsityl azide-iodosylbenzene' is subjectto rapid and atom of MN-dialkylanilines o-"-Uon n. f Azidonation, also undergo this u"Ot group'r Similarly' carbamates efficient introduction oiun transformation.2 with a temperature in a reaction azides3u' p-Alkyl anisoles lbrm benzylic I1ot instead of PhIo)' ,i*itu. reagentpair (PhI[oCoCFr]z v i c . D i a z i d e s . n T h e r a p i d a d d i t i o n o f t w o a z i d o g r o u p s t oThe t h e al-azido - a n d B - group p o s i t i oofn s proceeds in a trans manner' of triisopropylsilyl enol ethers nucleophiles' replacedby-various carbon these compounds is realily group to the carbon atom azide Introduction of an a-Azidonatioo o7 oia'i't attachedtothenitrogenutotofamides'carbamates'andureascanusethePhlOions are the intermediates' MerSiNr combination' N-Acyliminium (1993)' 'P. Magnus,J' Lacour'and W' Weber'JACS115' 9f4'l (19-9? 'p. f"fuinu, unOC' Hulme' TL 35' 8097 .. sL 42't (t994)' Mitoh, S' F"jill:1nd M' Gvoten' , y. Kita, H. Tohma,T. T.fi":;. (19'95)' 'P. Magnus,M' B' Roe' and C' Hulme' CC 263 (1994)' 'P. Magnus'C' Hulme'unOW' W'bt'' JACSf 16'4501
Trimethylsityl chloride. 15' 89: 16. & Iminiunt salts.t The preparation t moted bY MerSiCl. Cleavage of oximes and senicarl DMSO in refluxing MeCN, the clearrl Deconiugation of acYclic Pholo t of B-halo a,B-unsaturated ketones to t Silyl nitronates.a Intramolecular is induced by Me3SiCl-Et3N.It is a c dropyranaldehydesare obtainable fron Nitration of arenes's The mirtu fective nitrating agent in CClr' whrch yield).
' w. Jahnand W. Schroth, TL 34.5863t 19 tF. Ghelfi,R. Grandi,andU' M. Pagnoo tF.-T.Luo andL.-C. Hsieh,TL 35' 9Jt5 t oJ.L. Duffy andM. J. Kurth,JoC 5t' 3lt tG. A. olah, P. Ramaiah,G. Sandford'A
TrimethylsilYt cYanide. 13, 8?-88: I CyanohYdrins and ethcrc' Tan catalyst for the carbonyl derivatizatto derivatization of p-hydroxy ketorrs.: T MSOTf-catalyzed processis subicr duct of benzoquinonescan be redtra
iP'o..,,1
OMe I
MqSi}I'rrt
\
ct+&
T -
i-Pto 15' 5l; 16' 50 N-Trimethylsilyl(bisfluorosulfonyt)imide' Mukaiyamaaldoliaation.|Thissubstancecatalyzesreactionsbetweensilyl enol ethers and acetals' (1993)' S' Trehan'TL 34"1335 I A. Trehan,A' VU' M' Walia' G' Kaur' R' D' Verma'and Trimethylsilyt bromide' .-L:-^.:^n ^r Me.SiRr with an oxtThe combination of MerSiBr vic-Dibromid" ooi t'o^olactones' it converts carvone to the Thus with a RN*Mnot dant represent' u u'otin" source' acids is accomplished of unsaruratedcarboxylic 7,g-dibromide., B-.;j;;;zation in DMSO with Et3N as base'(1994)' andS' Basu'JCS(PI)166'l 'B.G. Hazra,M'D' Chordia'B'B' Bahule'V'S"Pore' (1994)' 841 JCS(P1) Iwata' C' no' runuka' and 2K. Miyashita,l. r.".i.,'ri."r"rlru*
Nitriles. AtlYlic cYanides arc (PhrP)aPd-catalyzedtransformatioo provides a way of controlled functiol tic.6 a-Cyano selenidesare products I with MerSiCN. Seleno-ortho esters I Ph\
/Ph
o-si-cl
llqs4t
Trimethylsilyl cyonide 3tl
,lr z:J ronizationgenerateszr-allylpalThe Iurr. the metal in an active state' ''. ?, (tin; nr MerSiNr is catalyzed bY
' J '
:
(1995)' [,u:: rnd L.-L. Yeung'IL 36, 107
5 Jr.rlkylanilinesis subjectto rapid and this rrnrLarlr.carbamatesalso undergo with a I i.,,'nr temperaturein a reaction o : P hI O ) . 0 slrJrr groupsto the a- and B-positions group of a '.(rfr.\manner. The l-azido xr-,rrbon nucleoPhiles' atom rn ,'l rn azide group to the carbon PhIOthe r.i\rnrles, and ureas can use ar. lhe intermediates' '.ir-
1993).
Trimethylsilyl chloride. 15, 89; 16, 85-86 Iminium salts.t The preparation from aldehydesand silyldialkylamines is promoted by Me:SiCl. Cleavage of oximes and semicarbazones.' Using MerSiCl in combination with DMSO in refluxing MeCN, the cleavagemethod is relatively simple. Deconjugation of acyclic B-halo enones.t MerSiCl catalyzesthe isomerization of B-halo d,B-unsaturated ketones to the corresponding B,y-unsaturatedketones. Silyl nitronates.a Intramolecular cycloaddition of p-propargyloxy nitroalkanes is induced by Me3SiCl-Et3N. It is a convenient way to dihydrofuraldehydes. Dihydropyranaldehydesare obtainable from the homologousnitro ethers. Nitration of arenes.s The mixture of Me.rSiCl, NaNOr, and AlClr form an effective nitrating agent in CCI+, which is probably NO2*AlCl4- (8 examples, 62-97Vo yield). 'W JahnandW. SchrothTL 34,5863(1993). , tF. Ghelfi, R. Grandi,and U. M. Pagnoni,SC 23,2279(1993). tF.-T.Luo andL.-C. Hsieh,7L 35, 9585(1994). o L. Duffy and M. J. Kurth, "/OC59,3783(1994). J. t G . A . O l a h .P . R a m a i a hG. . S a n d f o r dA.. O r l i n k o va. n dG . K . S . P r a k a s hS, 4 6 8 ( 1 9 9 4 ) . Trimethylsilyl cyanide. 13, 87-88; 14, l0'7; 15, 102-104;17,89 Cyanohydrins and ethers, Tetracyanoethylenehas been introduced as a new catalyst for the carbonyl derivatization.r KCN-ZnI2 is used to achieve 'tyrl-selective Exchangeofone alkoxy group ofan acetalin a derivatizationofB-hydroxy ketones.2 TMSOTf-catalyzed processis subjectto remote asymmetric induction.r The monoadduct of benzoquinonescan be reducedby SmI2 to give p-hydroxybenzonitriles.o
rt: ,rJ V. GYoten,SL 427 (1994)' l.-< .3i :,1994).
. l 5 5 l : 1 6 ,5 0 silyl leree catalyzes reactions between (1993)' ;r-': rnd S. Trehan'TL34,'7335
an oxif hc iombination of MelsiBr with -MnOq converts carvone to the it h . R.\ acids is accomplished carboxylic rturared (1994)' , P r.'. and S. Basu,JCS(PI)166'l (1994)' r[. rnd C. Iwata,JCS(Pl)847
9M"
9M"
OMe FPro. n A \/\,/\ I iPro
Me3SiCN- M63SiOTf cH2ct2, - 78o
N C z . n N C . n A
Y V \
*
t tsPrO
967"
Y V
: FPrO
(5 : 1)
Nitriles, Allylic cyanides are formed from the acetates or carbonates in (Phf)aPd-catalyzed transformations.5 Intramolecular cyanosilylation of alkynes provides a way of controlled functionalization of such compounds using a tether tactic.6 a-Cyano selenidesare products from SnCla-catalyzedreaction of diselenoacetals with MerSiCN. Seleno-ortho estersalso exchangeone selenogroup for the cyanide.T Ph
Ph
Ph
o-si-cl I \:
MegSiCN - (dba)gPde. CHCIa
o-bi'Ph (,\,"*
PhMe, A, 10h 57o/o
382 Trimethylsllylfluorosulfonate Isonitriles. In anodic reactions of o-heterosubstituted organotin compounds the CN group is delivered to the position vacated by the tin atom in the form of an isonitrile.s Interestingly, nitriles are obtained when the supporting electrolyte is changedfrom BuqNBFo1in THF) to Bu+NClOq(in CH:CI:t. t-Butylation of amines.e The condensation of acetone, amine, and MerSiCN affords an a-aminonitrile, which on further reaction with MeLi results in the formation of a t-butylamine. Pauson-Khand-type reaction.to In a cyclopentenone synthesis catalyzed by the titanoceneCp2Ti(PMer)2,trimethylsilyl cyanide suppliesthe carbonyl unit. 'T. MiuraandY. Masaki,JCS(PI)1659(1994). 'M. S. Batra,F.J. Aguilar,andE. Bruner,7 50, 8169(1994). 3c. A. MolanderandJ. P. Haar,JACS115,40 (1993). nS.H. OlsenandS.J. Danishefsky, TL 35,7901(1994) 5J.Tsuji,N. Yamada,andS. Tanaka,JOC SE,16(1993). oM. Suginome, andY. Ito, 7L 35, 8635(1994). H. Kinugusa, 7M. Yoshimatsu, H. Shimizu,M. Hori, andT. Kataoka'SL l2l (1993). T. Yoshiuchi, EJ.Yoshida,M. Itoh, Y. Morita,andS. Isoe,CC 549(1994\. tM. J. Genin.C. Biles,andD. L. Romero,TL34,43Ol (1993). 'uS.C. Berk,R. B. Grossman, JACS116'8593(1994). andS.L. Buchwald,
Tri methylsilyl(d iethyl)amine. a-Alkylation of conjugated carbonyl compounds.t Upon Mukaiyama aldolization and silica gel chromatography. The 1,4-adductsfrom reaction of enones with the original chromophore.A net a-alkylation on nonenolizable MerSiNEtz regenerate
Trimethylsilyl iodide. 16, 188-189 Vinyl iodides,r A convenient s)-nthcs tion and treatment of the products u ith \le
minutes at room temperature. Conjugate addition.2 z'-Altyliron cc gated carbonyl compounds in the prescncc Iodination of B-lactams. The.\-tcx1 51y2'displacementon the enol form.
' K. Lee andD. F. Wiemer,It 34, 24-1-1 r 199i, t K. Itoh, S. Nakanishi,andY. otsuji.lovc t t M . T e n ga n dM . J . M i l l e r ,J A C S1 1 5 . 5 . 1rtl 9 9
Tri methylsilyl trif luoromethanesu lforl 15, 346-350; 16,363-364: 17. 379--1t6 Dealkoxylative condensations. \un lyzed with TMSOTf. Glycosyl donors rrx and phosphinoxyglycosides.l
Under the influence of TMSOTf aclclx clic counterparts remain unaffected. Fcrm becausenew O-C and C-C bonds are crcr to mixed acetalsand oxathioacelalsrs nr nium ions, which then undergo S.l' rcr-r other hand, oxathioacetalsare clealed ulr
enals and enonesis realized.
OMe
I
,r._zY" o
Me3SiNEt2
R'r'-\'R' NEt2 OSiMe3
R3cH(oMe)z TiClr, CHzClz;
silica gel
RYoMe s"n^?\i{ o
'M. Hoio,M. Nagayoshi, K. Miura,andA' Hosomi'CL'719 A. Fujii,T. Yanagi,N. Ishibashi, (1994).
\-,
Lefo
OMe
-l
I B. H. Lipshutz,J. Burgess-Henry, andG. P. Roth,TL 34' 995(1993).
,/
The Mukaiyama aldolizationof o-sulfc A relatedreactionis the opening of p-o involving C-N bond cleavage.trappingrn TBSO
Tri methylsilyl f luorosulfonate. silyl donor and catalyst.' This compound FSOrSiMer, readily obtained by -78', is comparable and reaction of allyltrimethylsilane with fluorosulfonic acid at sometimessuperiorto trimethylsilyl triflate in catalytic activity.
\
llels'
1fou"
l )(tru" H Y u
l|:r9Ci
a
U
Carbonyl con d en sat ion s. Two-carbo condensation with B-silyl enol elhcrs trv
Trimethylsilyltriftuoromethanesulfonate
n .,h'tituted organotin compounds of an d :" rhe tin atom in the form is electrolyte supporting *r':r rhe ( ' H : C l : ) ' ir. n : rcetone' amine, and Me:SicN 11,5,$ tth MeLi results in the formaby k i : r r e n o n e s y n t h e s i sc a t a l y z e d unit' carbonYl .uPPlies the rrjt
383
Trimethylsilyt iodide. 16, 188-189 featuresenolphosphorylaVinyi iodides.L A convenient synthesis from ketones in MecN) for a few (or MerSiCl-NaI MelSiI with products tion and rreatment of the minutes at room temperature. Conjugateaddition.2n'.Allylironcomplexesdonatetheallylgrouptoconjugated carbonyl compounds in the presenceof Me:SiI' IoilinationofB-lactams.TheN-tosylatesgive3.iodo-B.lactamssasaresultof S7y2'displacementon the enol form' ' K. Lee and D. F. Wiemer,TL 34,2433 (1993)' 'K. Itoh, S. Nakanishi,andY. otsuji,JOMC473'215(1994)' tM. TengandM. J. Miller,JACSll5, 548 (1993)'
9
): F
: 9
: *9Jr ' L l2l (1993)' .-: T KataokaS .qJ |. q9l).
, a , . i l 6 . 8 5 9 3( 1 9 9 4 ) .
rtunds. UPon MukaiYamaaldolizawith !J,.t. from reaction of enones nonenolizable on c -\ net a-alkylation
13' 329- 33I ; 14' 333- 335; Trimethylsilyl trif luoromethanesulfona te' 15, 346-350; 16, 363-364; 17, 319-386 glycosylation reactions are cataDealkoxylative condensafions' Numerous isopiopenyt'r trichloroacetimidinyl,2 lyzed with TMSOTf. Glycosyl donors include and phosphinoxYglYcosides.r react with allylsilanes'owhile cyUnder the inf luence of TMSOTf acyclic acetals of 5,6-dihydropyranstis interesting clic counterpartsremarn unaffected.Formation becausenewo-CandC-Cbondsarecreated,Thetransformationofally|icacetals by MezS via l'3-transposedsulfoto mixed acetalsand oxathioacetalsis mediated niumions,whichthenundergosly2,reactionswithalkoxidesorthiolates,nonthe otherhand,oxathtoacetalsarecleavedwhenp-nitrobenzaldehydeispresent'7
z,^--rr\olrr" a'CH(OMe)z - Cl1.CH2C|2;
R3Y.oMe
+
(-.J
Me3sil Me35iO
CHzQlz .7go -> 00 2h 76o/o
R"nz\e b
srl@gel
o
CL'l19 . | . , . r r . K . M i u r a , a n d A ' H o s o m 'i
is an'i-selective'o The Mukaiyama aldolizationof a-sulfenyl acetals with TMSOTf-MeCN of B-methoxy-B-lactamse A related reaction is the opening of a water molecule' transfer and MeCN with t'upping involving C-N bond .l"uuug", TBSO I
obtained bY ou:J FSOrSiMer, readilY -?8', and comparable is rl:,,rre acid at In,rtrl\tic activitY' r . . . ' - l t . 9 9 5( 1 9 9 3 ) .
OMe I
a\ NH H- !,'" il
o
OMe
TBSO MecSioTf/MecN oo
.
1 l -v
-NHAC
.
CN 71./.
Carbonylcondensations.Two-carbonhomologationofcarbonylcompoundsby a,B-unsaturated aldehydes.r0Dual-site condensation with B-silyl enol ethers gives
384 Triorganoboranes re1,3-butadiene condensationof 1,4-ketoaldehydeswith l, 1,3-tris(trimethylsiloxy)sults in the oxabridged system.rr
-cHo
V
Ph
t"tt'o>-o""
*
MessiOTf
fo"*""
CH2Q!2
.T! ,/ Ph 87"/o
Conjugated thionium species are generated from allyl sulfoxides. Trapping of these specieswith silyl enol ethers leads to vinyl sulfides.12 Rearrangements. lreland-Claisen rearrangementof allyl fluoroacetates,rrformation of p-(N-acylamino)aldehydes from O-vinyl-N,O-acetals,'o 1,2-group migra-
Stereoselective radical addition to dl EtrB has been usedas a catalystfor the rertrc Benzyl alcohols.a The preparation tntt zones with RrB in the presenceof an amrtr [yielding ArCH(OH)R]. As a variation of tl and addition of H:O prior to workup gives ,
Electrophilic activation ol allylic dct triphenylborates enables the Pd(O)-catallzc nucleophiles such as malonate ester enolatc
' R . - Y .Y a n ga n dL . - X D a i ,S 4 8 1( 1 9 9 3 ) . rE. BaciocchiandE. Muraglia,TLS4'5015| 19 t K. Miura,K. Oshima,and K. Utimoto, ECSJa tG.w Kabalka,J.T.Maddox,andE. Bogas..lo( ' 1 . S t a r y I, . G . S t a r aa, n dP . K o c o v s k y ' T L J { .l '
tion/trapping are some of the useful transformations initiated by TMSOTf.rs16 'H. K. ChenaultandA. Castro,ft 35,9145(1994). ' J . - A . M a h l i n ga n dR . R . S c h m i d ts, 3 2 5( 1 9 9 3 ) . rH. Kondo,S. Aoki, Y. Ichikawa,R'L. Halcomb,H. Ritzen,andC.-H. Wong,'/OC59' 864 (1e94). os. Kim. J.Y. Do. S.H. Kim, andD. Kim, JCS(PI)2357(1994). 5I. E. MarkoandD. J. Bayston,r 50, 7l4l ( 1994). uS.Kim. J. H. Park,andJ. M. Lee,TL34' 5'169(1993). 7T.Ravindranathan, S.W.Dantale,andR.B. Tejwani,CC 1937 S.P.Chavan,J.P.Varghese, ( 1994). tK. Kudo,Y. Hashimoto, andK. Saigo,JOC 58,579(1993)' M' Hasegawa, M. Sukegawa, tY. Kita. N. Shibata,N. Yoshida, JOC59' 938(1994)' N. Kawano,andK. Matsumoto, l"L. Duhamel,J. Gralak,andA. Bouyanzer'TL34'7'145 (1993)' " G. A. MolanderandK. O. Cameron, JACS115'830(1993). 'tR. Hunter,J. P. Michael,C. D. Simon,?d D. S. Walter,T 50,9365(1994)' lrK. Arak and J.T. Welch,IL 34,2251 (1993). roH.Frauenrath, T. Arenz,G. Raabe,andM' Zorn,ACIEE32'83 (1993)' 'tq. Liu, M.J. Simms,N. Boden,andC. M. Rayner,JCS(PI)1363(1994). 'ul. ColdhamandS. Warren,JCS(Pl)1637(1993).
Triphenylphosphine. Deoxygenation of alcohols.' Aldohok ence of PhrP to give alkanes. 2,4-Alkadienones and 2,4,6' alhatrica 4-hydroxyl derivativesare converted to thc a
temperaturein benzene.4-Hydroxy-2-alk1t A cocatalyst for the isomerization of al phenol.3 Reducti.on-substitution of 2-alLytit triple bond of 2-alkynoic acid derivativesrt ung senseis effected by catalytic amounts I
Drocessesinvolve 2,4-dienoic intermediatcr
^ w
r| Ji
\\
COOMe \ -cooM"
+
"|\t io
\ X = OMe,NMea
Trimethylsilylmethylmagnesium chloride- l5' 343 Treatment of the conjugate (Jnsaturated nitriles from L-nitrocycloalkenes.r fragmentation. desilylative PClr triggers with reactions adducts from the Grignard ' H . - H . T s o ,B . A . C i l b e r t a , n dJ .R . H w u ,C C 6 6 9( 1 9 9 3 ) . Trlorganoboranes. 15, 337 N-Tosylamines,t Reaction of R3B with TsN:IPh in THF gives RNHTs in 6099Vo yield.It is not known whether ArrB would undergo the same transformation. Homolytic heteroaromatic substitutions.2 EtrB is often used in promoting free radical reactions, including alkylation of heteroaromaticssuch as pyrrole derivatives with alkyl halides.
o J
l
trleo'\ \..2R
*
^
r
y
R'Ofl ;
o
O|l \
COOMe
Ph3P-HOAG/ Or|SO dppp-HoAc / Phra
3E5 TriphenYlPhosPhine re-r::. lilmethylsiloxy)-1,3-butadiene
E.s.:-'
,,T\ l b F o t/ 87"/o
tcJ !r()m allyl sulfoxides' Trapping of r n rI . u l f i d e s . r 2 forrulgement of allyl fluoroacetates,13 )-r rni l-MO-acetals,ra1,2-groupmigramrt r\,nsinitiated by TMSOTf'rs'r6 IJ
864 b fi Rrrzen,andC.-H' Wong,JOC 59' P. :1r' (1994). 193'l ! \ \\ Dantale,and R. B' Tejwani'CC (1993)' i ; ; . : . . r o dK . S a i g oJ, O C 5 E , 5 7 9 (1994)' 938 59' JOC N l, \latsumoto' --r5 (1993). ]!{ , ri
1993).
i \ \ : . : e r .f 5 0 .9 3 6 5( 1 9 9 4 ) '
stereoselective radicul addition to alkynes und reduction of iodoalkynes.3 EtrB has been usedas a catalystfor the reactionswith (MetSihSiH to yield (Z)-alkenes' Benzyl alcohols.a The preparation involves reaction of araldehyde tosylhydrazones with RrB in the presenceof an amine base (e.g., DBU) followed by oxidation [yieldingArCH(OH)R].Asavariationofthismethod,theuseofBu+NOHasbase and addition of HzO prior to workup gives ATCH2R' Electrophilic activation of atlytic alcohols.s Formation of lithium allyloxytriphenylborates enables the Pd(0)-catalyzed substitution of allyl alcohols with soft nucleophiles such as malonate ester enolates. ' R . - Y .Y a n ga n dL . - X D a i ,S 4 8 1( 1 9 9 3 ) . 2 8 . B a c i o c c hain dE . M u r a g l i a ' T L 3 4 , 5 0 1(51 9 9 3 ) ' 'K. Miura, K. Oshima,and K. Utimoto,BCSJ66' 2356(1993). oc.w. Kabalka,J.T.Maddox,andE. Bogas,JOC 59,5530(1994)' t l. Stary,I. G. Stara,andP. Kocovsky,TL 34, 179(1993)' TriphenylphosPhine. Deoxygenation of alcohols.' Aldohols undergo double electrolysis in the presence of PhrP to give alkanes. 2,4-Alkadienones and 2,4,6-alkatrienoic esters. Both 2-alkynones and their 4-hydroxyl derivativesare converted to the dienones'by treatment with Ph:P at room temperature in benzene.4-Hydroxy-2-alkynoic esters behave analogously. A cocatalyst for the isomerization of alkenynoic esters to the trienoic esters is phenol.3 Reduction-substitution of 2-alkynoic acid derivatives.a Reduction of the triple bond of 2-alkynoic acid derivatives with functionalizaiion at C-4 in the umpolThese ung senseis effected by catalytic amounts of PhrB HoAc, and a nucleophile. processesinvolve 2,4-dienoic intermediates. n
r'. \ ( r E E 3 2 , 8 3( 1 9 9 3 ) . tCstPI)136l(1994) Int
X
\
,Adcoor"
NaOAc/ PhMe
!
COOMe
O
PhsP -HOAC
80-1100
X = OMe,NMez
r. 15.l-13 lulkenes.t Treatment of the conjugate trrugersdesilylativefragmentation' {. 6!
o *o\*
+
R'OH
Ph3P-HOAC
o
r"oA7y*
PhMe,90-1100
oR'
!q11.
rh T.\:IPh in THF givesRNHTsin 60rou.J undergothe sametransformation' lr.' Et.B is oftenusedin promotingfree irer\'rromaticssuchas pyrrolederivatives
COOMe PheP-HOAc/DMSO 91 3 dpip-HOAc/ PhMe
: :
9 97
tetrahalides 3E6 Triphenylphosphine-carbon
Tritfr
4- Pentenenitriles and benzoff lindoles. Allyl iminophosphoranesare formed from the corresponding azides upon treatment with PPhr (Staudingerreaction). Condensation of these products with diaryl ketenes leads to 4-pentenenitrilessby a sigmatropic rearrangement. In the homoallyl series the Wittig reaction is followed by an intramolecular Diels-Alder reaction. Mild dehydrogenationof the products gives benzo[/]indoles."
PPh3
Ph2c=c=o
Ph-.22-v.N3 PhH, t h, A
]
rt, 15 min
,5
['frl
l " en^en.J ?f i1 I
['n,.,..--*="'*
Monoesterification
o .Mo(CO)5
rlr
lll OMe
I Ph
Ph3P
-*
T H F ,A
of saccharidcs.
sugarsare selectively acylated under Mitsu Alkylations. The reagent effects redr indole derivatives3 with alcohols. Thc Mi acrylic estersaand that of glycals wirh ph
2,4-Cycloheptadienones.l Cyclopropylcarbene-Mo complexesreact with alkynes in the presenceof Phf under relatively mild conditions. The products are 2,3di substituted4 -alkoxy-2,4-cycloheptadienones.
1
'Y. Kikugawa, L. H. Fu, andT. Sakamoro. 5C i 'K. Tamura,H. Mizukami,K. Maeda,H. \tnre t A. K. Saikia,N. C. Barua,R. P. Sharma.andI oY. Kubota,M. Kodaka,T. Tomihiro, and H O Triphenylphosphine -diethyl ezodictrbr 17, 389-390
reaction) 51%(one-pot
Ph
Conjugated nitroalkenes.3 Dehydrrr combination in the presenceof RN is ao r Cyclic urethanes.a Carbon dioxi& ir from amino alcohols in the presenceof P the halides with other P(III) reagentssut effective.
,-)L_JP\ / \ \ . - , ^pn bue 52"/"
'H. Maeda,T. Maki, K. Eguchi,T. Koide,andH. Ohmori,TL35,4129(1994). 'C. Guo andX. Lu, JCS(PI)l92l (1993);CC 394(1993). rS. D. Rychnovsky andJ.Kim, JOC 59,2659(1994). 4B.M. TrostandC.-J.Li, JACS35, 3167,10819 (1994). tP. Molina,M. Alajarin,C. Lopez-Leonardo, andJ. Alcantara,I49,5153 (1993). 'P. Molina and C. Lopez-Leonardo, TL 34,2809 (1993). 7J.W.HerndonandM. Zora,SL 363(1993).
Triphenylphosphine-carbon tetrahalides. 13, 331-332; 15, 352; 16, 366-368 Acid halides. The relatively mild conditions of converting acids to halides by Phf-CX4 can be exploited for a one-flask synthesis of N-methoxy imidoyl bromides,r which give rise to nitriles on photolysis. In the presenceof Et:N the Ph:rPCXa combination converts amines and CFTCOOHto trifluoroacetimidoyl halides.2
has been applied to the inversion of col whereas alkyl nitriles are prepared by thrs
the source of nucleophile. The C-alkylatro zylic position is easily controlled. Inversion of hindercd alcohols.t lo tl ship between dissociation constant of th. r efficiency is indicated. Product yields en Among substituted benzoic acids, 4-nirro. tives give better results.
'A. Bourhim,S. Czernecki, andP. Krausz..fC 2A. Garcia,L. Castedo,and D. Domingrrs. S{. 'S. S. Bhag*at and C. Gude,It 35, 1847( t99a oA. B. Charetteand B. Core,It 36, 6833( t99! tA. Sobtiand G. A. Sulikowski,IL 35. 3661( | uE.G. J.C. Warmerdam, J. Brussee, C. G. Krur tJ. E. Macorand J. M. Wehner.H 35. 349 ( l99l tJ. A. Dodge,J. I. Trujillo, and M. Presncll. .lO
Triphenylphosphine-diisopropyl erodb Gaanidines.t An exceptionally mild r of a modified Mitsunobu reagent comhl derivative. Closure of oxacycles. Terminal cpor l, 2, 3-tr iol s. B -Lactonization I proceeds r rrI the yields are poor.
3E7 azodicarboxylate Triphenylphosphine-diisopropyl are formed 11. rnrrnophosphoranes rh PPh, {Staudingerreaction)'Conby a sig.3J. to -l-pentenenitriles5 111 \\'rttig reaction is followed bY hri:,'senation of the productsgives
Conjugated nitroalkenes.3 Dehydration of p-nitro alcohols by this reagent combination in the presenceof R3N is an improved method' Cyclic urethanes.a Carbon dioxide is activated for the heterocycle formation from amino alcohols in the presenceof PhrP and CCI+ or C2Cl6. Combinations of the halides with other P(III) reagentssuch as Bu:B (MeO)rB and (PhO)rP are also effective.
"
'l .t _ ppho
Ph2c=c=o rl' 15 min
I
:"'"
rea:: on )
xnc \to comPlexesreactwith alkYLi -,'nditions. The products ate 2,3-
o II
f
l
./'\r/
Ph
\ OMe
52"/.
b: ::. fL 35'4129(1994)' Q*i I
): { -jrtrra, f49,5153 (1993)' F:
-t : II --132;15,352;16,366-368 acidsto halidesby nr.. \,f converting r):rhe\is of N-methoxYimidoYlbroof EtlN the Ph3Pr. ln the presence halides'2 OH l,r trifluoroacetimidoyl
'Y. Kikugawa,L. H. Fu, andT. Sakamoto, SC23, 106l(1993)' 'K. Tu.u.u, H. Mizukami,K. Maeda,H. Watanabe, JOC 58,32(1993)' and K. Uneyama' ' A . K . S a i k i aN , . P .S h a r m aa, n dA ' C . G h o s hS, 6 8 5( 1 9 9 4 ) ' , . C . B a r u aR oY. Kubota,M. Kodaka,T. Tomihiro, and H' Okuno,JCS(P|)5 (1993)' -337 : Triphenylphosphine-diethyl azodicarboxylate. 13, 332; 14, 336 17. 389-390 Monoesterification of saccharides.t The primary hydroxyl groups of these sugarsare selectively acylated under Mitsunobu reaction conditions' Alkylations. The reagenteffects reductive N-alkylation of N-tosylamines2 and indole derivatives3with alcohols. The Mitsunobu reaction of 2-(l-hydroxy-alkyl)acrylic estersaand that of glycals with phenolssfollow an Siy2'course. The reaction has been applied to the inversion of configuration at an a-cyanohydrin center'n whereasalkyl nitriles are prepared by this method using acetonitrile cyanohydrin as at the benthe sourceof nucleophile.The C-alkylation of o-nitroarylacetonitrilesT zylic position is easily controlled. Inversion of hindered alcohols.s In the Mitsunobu reaction a positive relationship between dissociation constant of the acid component (nucleophile)with reactron efficiency is indicated. Product yields are higher when using acids of lower pK"' Among substituted benzoic acids, 4-nitro, 4-methanesulfonyl, and 4-cyano derivatives give better results. fA. Bourhim,S. Czernecki, andP. Krausz,JCC 12,853(1993). 2A. Garcia,L. Castedo, SL 271(1993). andD. Domingues, tS. s. Bhagwatand C. Gude,TL35, 184'l(1994). oA. B. ChareueandB. Cote,TL 36, 6833(1993). t A. Sobtiand G. A. Sulikowski,TL 35,3661(1994). oE.G.J.C.Warmerdam, C.G. Kruse,andA. van derGen,749' 1063(1993)' J. Brussee, tJ. E. Macorand J. M. Wehner,H 35,349 (1993). tJ. A. Dodge,J. L Trujillo, and M. Presnell,JOC 59' 234 (1994)' Triphenylphosphine -diisopropyl azodicarboxylate. 15, 352 353; 17' 390 Guaniilines.t An exceptionally mild alkylation method for guanidine is the use of a modified Mitsunobu reagent combination and an alcohol en i15 fy',1ty''-diBoc derivative. Closure of oracycles, Terminal epoxides are formed2 selectively from acyclic 1,2,3-triols.p-Lactonization3 proceedswith total inversionofconfiguration, although the yields are poor.
3E8 Triphosgene ' D. S. Dodd and A. P. Kozikowski, TL 35,9'l'l (1994). 2C. Gravier-Pelletier, Y. Le Merrer, and J'-C' Depezay, SC 24' 2843 (1994). tS. C a m m a s , I . R e n a r d , K . B a u t a u l t ,a n d P . G u e r i n , f A 4 , 1 9 2 5 ( 1 9 9 3 ) .
Triphenylphosphine-dipyridyl disulfid e. 13' 332-333 Amides.t Activationof carboxylicacidsby this reagentcombinationfollowed by reactionwith MerSiNR2constitutesan efficientmethodof amidesynthesis. 'R.
Di Fabio, V. Summa, and T. Rossi, TL 49' 2299 (1993).
16' 369 Triphenyltin hydride-trialkylborane. Radical cyclization.t The intramolecular free radical addition to an aldehydein order to form a cyclohexanol is induced by Ph:SnH-EtrB in the presenceof air. Hydrostannylation,2 Alkenes do not generally undergo this reaction. However, cyclopropenesare hydrostannylatedwith Ph3SnH-Bu38 becauseof their ring strain. 'D. L. J. Cliveand M. H. D. Postema, CC 429(1993). 'S. Yamago,S. Ejiri, andE. Nakamura, CZ 1889(1994).
Triphosgene. Anhydrides and cyclic carbonates. Symmetrical anhydrides are formed when acids are rreated with (ClrCO)zCOand Et3N.r The transformation of the terminal glycol unit of a 1,2,3-triolto the cyclic carbonate2can be accomplishedwith triphosgene and pyridine; on the other hand, the internal diol system is protected using NaH and
Tris(4-bromophenyl)aminium selts. l{. Glycosylation' The one-electronort
fides toward coupling with alcohols tinclrr 1,2-Rearrangements. Efficient prnr temperature.a-Substituted arylacetabc\ dicarbonyl compounds with an analogorr t
Desulfurization.a Allyl and diallll t temperatureto give dienes and trienes. rcsp
' Y . - M . Z h a n gJ, . - M .M a l l e t ,a n dP . S i n a 1C .f tL. Lopez,G. Mele,andC. Mazzeo.JCSPl , ' tL. Lopez,G. Mele,A. Nacci,andL. Trcxsr./ oV.Calo,L. Lopez,A. Nacci,andG. Ileb. f !
Tris(dibenzylideneacetone)d ipallrd ir r. Adtlition lo unsaturated systcas. A lyzed reaction of conjugated dienes. orge chloride componentis incorporatedrnto tl
P h c o c +l V \ + f b l 9 - s ' -
(MeO)zCO.
Addition of Bu3SnHto enynesis regro readily available.C1cl rretr nyl- 1,3-dienes2 carbonylation is a useful way to acces fuo enes undergo reactions at both ends: r tth allylamines bearing an crr-arylgroup'
o o
o
"H,,'" BnO.--
\OX
(MeO)rCO rl
65"/"
chlorides.t
A combination
of triphosgene and PhrP is effective in the conver-
sion of alcohols to chlorides. Conditions are mild (typically 0'C, 5 min., in CHzClJ. 'R. Kocz, J. Roestamadji, and S. Mobashery, JOC 59' 2913 (1994). 'S.-K. Kang, J.-H. Jeon,K.-S. Nam, C.-H. Park, and H.-W. Lee, SC 24,305 (1994)' t l . A . R i u e r o , R . S o m a n a t h a n ,a n d L . H . H e l l b e r g ,S C 2 3 ' 7 l I ( 1 9 9 3 ) '
Allylic substitutions. Allllic carbo ethers,5amines,6 sulfides? on exposurt tr Pdz(dba)r,and a tertiary phosphine, Allylic compoundscontaining orhcr lc stitution. Thus alkoxycarbonylationof ell tion, on which an interesting p-lrtam
nucleophile in the displacement.2.'t-hcrd dienyloxiranes. Desilylation of the prodrx Either the S1y2or the S1y2'path*a1 for propane" can be selectedby using .\'-nrrl
Tris(dibenzylideneacetone)dipalladiun
389
Tris(4-bromophenyl)aminium salts. 14, 338; 16,369-370:' l7' 391 The one-electron oxidant promotes activation of glycosyl sulGlycosylation' fides toward coupling with alcohols (including sugars). 7,2-Rearrangements. Efficient pinacol rearrangement2is completed at room temperature. a-Substituted arylacetaldehydes undergo rapid oxidation to give d-
t ,r! \( 2{. 2843(1994). r 1 . l 1 9 2 5( 1 9 9 3 ) .
!r :rr. reagentcombinationfollowed irer.: methodof amide sYnthesis.
f frrc radicaladditionto an aldehydein ;Snl{-EtrB in the presenceof air. lr.rilr undergothis reaction.However,
salt.r dicarbonyl compoundswith an analogoustris(2,4-dibromophenyl)aminium Desulfurization,a Allyl and diallyl thiiranes undergo desulfurization at room temperatureto give dienes and trienes, respectively,on exposureto the aminium salt. 'Y.-M. Zhang,J.-M. Mallet,andP. Sinay,CR 236,73(1992). tL. Lopez,G. Mele,andC. Mazzeo,JCS(PI)779(1994). 'L.Lope., G. Mete,A. Nacci,andL. Troisi,TL34,389'l (1993). o V .C a l o ,L . L o p e z ,A . N a c c ia, n dG . M e l e , 7 5 1 , 8 9 3 5 (1995).
rH Uu,B becauseof their ring strain.
Tris(dibenzylideneacetone)dipalladium.14,339;15,353-355;16,372;17,394 Addition to unsaturated systems. Allylsilanes are produced' in a Pd(0)-catalyzed reaction of conjugated dienes, organodisilanes, and acid chlorides. The acid
F:
chloride componentis incorporatedinto the product after decarbonylation.
mcrrrcalanhydridesare formed when hc :rensformationof the terminal glyca.. b!' accomplishedwith triphosgene i.l .rrtem is protectedusing NaH and
ct3co)20 -7tr
H O H ^
13"7o
Bno)
Lo 77"/"
r ::J PhrP is effective in the converi l r : r p i c a l l y0 ' C , 5 m i n . , i n C H : C l z ) . t9 :.lr (1994). N ll ,\t' Lee, SC24,305 (1994). 'l t( :-r. I ( 1993).
pd(dba)2
phcoo
+ \A
+
Me3si-siMe3
,*"T0"
zr
Ph/ \/
,2,^
\/-
. _SiMes
86"/"
thus making 2-stanAddition of BurSnH to enynesis regio- and stereoselective, readily available.cyclization of allyl 2-alkynoateswith simultaneous nyl-1,3-dienes2 dicarbonylationis a useful way to accessfunctionalized7-lactones.'Nonconjugated enes undergo reactions at both ends; with aryl iodides and amines the products are allylamines bearing an a-aryl group.o Atlylic substitutions. Allylic carbonates are converted to the corresponding ethers,samines,6 sulfidesT on exposure to various nucleophiles in the presenceof Pdz(dba)r,and a tertiary phosphine. Allylic compounds containing other leaving groups are also reactive toward substitution. Thus alkoxycarbonylation of allylic phosphates8is a method of homologation, on which an interesting B-lactam synthesisqis based. using PhrSioH as from butaare synthesizedr0 nucleophilein the displacement,2,4-hexadiene-1,6-diols dienyloxiranes. Desilylation of the products is achieved with KF. Either the Sry2or the Sry2'pathway for the substitution of l-tosyloxy-l-vinylcyclopropane" can be selectedby using N-nucleophiles of different sizes.
390 Tris(dibenzylldeneacetone)dlpalladium NaNg/Pd(dba)z-PPhs 1s-crown-s; PPh3/ aq. NaOH
OTs
x,
NHc
60"/"
X/
Bn2NH/Pd(dba)2-dppf 1s-crown-s ;
PPfu/ aq.NaOH
rNBnr
NJ l/' 85"/.
Intramolecular substitutionsinvolving an allylsilane moiety12as well as following a metallo-ene reaction pattern13have been reported. Tandem metallo-ene cyclization and vinylstannane coupling serve to construct cycloalkanes with vicinal alkenyl chains.ro
Arylquinones,2rarylallenes,22dienl'l sul more unusual molecules whose assemblr tr cross coupling with a-alkoxyalkenylstan proach to enol ethers of defined configurer A technical modification of the Stillc c
polymer support.26 Suzuki coupling. This coupling usc preferred in the preparation of drug cea
In a synthesis of methll I carbapenems.2T pling is aided by AgrO." Heck coupling. An intramolecular ll pare 4-methylcoumarin2eand related coml chiral BINAP to mediatecyclization.an rl 86Voee.3o
Pd(dba)2
s02Ph r_kso2Ph
2) a.o)
ll
/rl \ Pt(^) \
"
/
,/3
Bu3SnCH=CH2 2nol2,IHF th, A
s02Ph
f-tso,Ph
fr
PivO_.
a-(-\ ,o."Q-,,oJ
)
Pd2(dba)3.CHCl3
(F)€rNAP/Kpq - CICH€HP I-BUOH
76%
Nucleophiles for the substitutioncan be generatedin situ. For example, a synthesis is conductedusing amines and alcoholsunder of allylic carbamatesand carbonates15 COz. Since disilanes are cleaved in the presenceof Pd(0) complexes,their use in the synthesisof allylsilanes'6is feasible. The formate anion reducesallylic acetatesin the ,Sp2'mode. Acquisition of allylic geln-bimetalliccompoundsrT is facilitatedby this process.
tlessiylronc BusSn
Pdz(dba)s- PPha HCOOH - EISN dioxane, A
Messi.ul I BusSn 99lo
Deallylations. The facile cleavageof the allyl group from esters,rscarbonates,re and carbamatesby nucleophiles(amines and thiols) in the presenceof a Pd(0) complex makes them useful derivatives for protection purposes. Stille coupling. The many examplesdescribing applicationsof this C-C bondforming method attest to its versatility. A comprehensivestudy of the coupling of arylstannanes with sulfonates has appeared.2oOf course, various combinations of aryl/aryl, aryl/vinyl, and vinyl/vinyl couplings are equally possible. PhrAs is often added to the reaction media. and in other casesCuI acts as a cocatalyst.
6-endo-trig Cyclization has been rcalrz
"a\
.d
Br--.2-pt
Y
Molecules with activc ( Alkylations. compounds that are activated by Pd catel and allenes.3rBy a thr lated by aldehydes32 ester, an allene, and a vinylic bromide. thc tutes a convenient preparation of a l..l.l Some aryl(hydro)silanesalso undergoar;.' R \==---
.cooEl I
?.. -.\
or'\
Fa|.
Tris(dibenzylidencacetone)dipalladiun .9+ *
,NHA
l>\/
F
60% r tc'
NBn2
65-/o
2s w e l l a s f o l l o w i n g t i i r l . r l a n e m o i e t y 1a p,'rred.Tandemmetallo-enecyclization ru.r cycloalkaneswith vicinal alkenyl
391
Arylquinones,2rarylallenes,22dienyl sulfoxides,23and dienynes2aare some of the more unusual molecules whose assembly is greatly simplified by this method. The cross coupling with a-alkoxyalkenylstannanes2s (and zincs) provides another approach to enol ethers of defined configuration. A technical modification of the Stille coupling is to anchor the aryl iodide on a polymer support.26 Suzuki coupling. This coupling uses nontoxic boronic acids; therefore, it is preferred in the preparation of drug candidates such as z-aryl- and 2-alkenylcarbapenems.2T In a synthesis of methyl 2-aryl-2,3-butadienoatesthe Suzuki coupling is aided by AgrO." Heck coupling. An intramolecular Heck coupling is a convenient way to prepare 4-methylcoumarinzeand related compounds. Through ligand exchange with a chiral BINAP to mediate cyclization, an intermediate for vernolepin is accessiblein 86Voee.3o
SO2Ph
I
f-tso2Ph
(Y
:l-
.Y^\ ,o""Qrro!
j
)
Pd2(dba)3.CHCl3 (F)€tNAP/K2CO3 I-BUOH- CICH2CH2CI 600
76"h
'ncr.rtedin situ. For example,a synthesis du;red using amines and alcoholsunder n;c "f Pd(0) complexes,their use in the r ::r rhe Sp2'mode. Acquisitionof allylic ' r5r\ process.
I
:
:
"
;...'I
'
g
Me3Si.,1 Y \ ' aussrl g
%
carbonates,le c .r.lrI group from esters,18 I rr:,'l\) in the presenceof a Pd(0) comC l t , ' nP u r P o s e s . s":rf'rng applicationsof this C-C bonditrmFrehensivestudy of the coupling of l.: oi course,various combinationsof rg. :re eQuallypossible.Ph:As is often lc. C'ul acts as a cocatalyst.
o. \_o
PivO..
PivO..
76"/. (86"/" eel
6-endo-trig Cyclization has been realized.rl
"a\ + tr..Z-rn
(dba)gPdz€HClg
Ph3P Et3N-PhMe
Y
62"/"
Alkylations. Molecules with active C-H and Si-H bonds add to unsaturated compounds that are activated by Pd catalysts. Substituted malononitriles are alkylated by atdehydesr2and allenes.33By a three-component coupling of an acetoacetic ester, an allene, and a vinylic bromide, the construction of a diene keto ester constitutes a convenient preparation of a 2,4,S-trisubstituted benzoic ester precursor.3a Some aryl(hydro)silanes also undergo arylation.35 R R
I \^v't\ Br I
-.,\
acooEl o7--
Pd2(dba)3- dppe
\.^.'.cooEr t l .^{-,
THF
- 70"/"
392 Tris(dibenzylldenercetone)dipalladium Cyclization of polyenynes.36 Very impressivereaction sequencesof ring formation from properly distanced multiple bonds are revealed. OMe
Pd2(dbah.CHC13
Ph3P/THF, A
Phso2
Phso2 n = 2.3.4
n= 4
77"/"
Other synthetic reactions. Catalyzedelimination of allylic carbonatesrToccurs in the absenceof nucleophiles.Alkynediols undergo isomerization and dehydration, furnishing 2,S-disubstituted furans3Eas a result. l-Carboranyltributyltin adds to aldehydesunder the influence of the Pd catalyst to form carbinols.seThe Pd version of a Pauson-Khand cyclopentenonesynthesis is accomplishablein the presenceof CO, and actually this version is specially suited for a one-step construction of d/methylenecyclopentenones.ao
(dba)3Pd2€HCl3
z
-X E
\
-//'..-oA" -
Ph3P, LiCt, CO
E
THF, H2O 700,24h
E
E=COzMe 'Y. O b o r a , Y . T s u j i , a n d T . K a w a m u r a ,J A C S 1 f 5 , 1 0 4 1 4( 1 9 9 3 ) . 'B. M. Trost and C.-J. Li, S(Spec. Issue) 1267 (1993). rJ. Ji and X. Lu, I50, 9067 (1994). a R . C . L a r o c k , Y . W a n g , Y . - D . L u , a n d C . E . R u s s e l l ,J O C 5 9 , 8 1 0 7( 1 9 9 4 ) . tR. Lakhmiri, P. Lhoste, B. Kryczka, and D. Sinou,JCC 12, 223 (lgg3). 6H. Inami, T. Iro, H. Urabe,and F. Sato,TL34,5glg (lgg3). tC. G o u x , P . L h o s t e , a n d D . S i n o u , T 5 0 , 1 0 3 2 1( 1 9 9 4 ) . 8S.-i. M u r a h a s h i , Y . I m a d a , Y . T a n i g u c h i , a n d S . H i g a s h i u r a , J O C 5 E , 1 5 3 8( 1 9 9 3 ) . eH. T a n a k a , A . K . M . A b d u l H a i , M . S a d a k a n e ,H . O k u m o t o , a n d S . T o r i i , J O C 5 9 , 3 O 4 O 0994\. 'oB. M. Trost, N. Ito, and P. D. Greenspan, TL 34, l42l (1993). "P. A u f r a n c , J . O l l i v i e r , A . S t o l l e , C . B r e m e r , M . E s - S a y e d ,A . d e M e i j e r e , a n d J . S a l a u n ,? L 34,4193 (1993\. 12M. T e r a k a d o ,M . M i y a z a w a , a n d K . Y a m a m o t o ,S t 1 3 4 ( 1 9 9 4 ) . 'tK. H i r o i a n d K . H i r a s a w a ,C P B 4 2 , 7 8 6 ( 1 9 9 4 ) . ''W. Oppolzer and J. Ruiz-Montes, IICA 76, 1266 (lgg3,. 'tW. D. Mcchee, D. P. Riley, M. E. Christ, and K. M. Christ, OM 12, l42g (lgg3). 'uY. Tsu.|i,S. Kajita, S. Isobe, and M. Funato, JOC 58,3607 (1993). " M. Lautens and P. H. M. Delanghe, ACIEE 33,2448 (1994).
'tS. Okamoto, N. Ono, K. Tani, Y. Yoshide. rr 'tJ. P. Genet, E. Blart, M. Savignac, S. L-cmr 680 0993). 20V. Farina, B. Krishnan, D. R. Marshall, eod r 2r L. S. Liebeskind and S.W. Riesinger. .rOC Sl "D. Badone, R. Cardamone, and U. Cuzzr. rI, "R.S. Paley and A. de Dios, IL 34,2429 (t9{, 2aB. H. Lipshutz and A. Alami, IL 34, I4ll r tr tt S. Casson and P. Kocienski, JCS(Pt) l lt? r t9 26 M. S. Deshpande, TL 35, 5613 (1994). ''N. Yasuda, L. Xavier, D. L. Rieger, Y. Lr. A ( 1993). "T. Cillmann and T. Weeber. SI 649 fl99ar 2eM. Catellani, G. P. Chiusoli, M. C. Fagoolr. r sK. K o n d o , M . S o d e o k a ,M . M o r i , a n d M . S b i 3'B. M. Trost and J. Dumas, TL 34, 19 (199f t 12H. Nemoto, Y. Kubota, and Y. Yamamoro. C( 13Y. Y a m a m o t o ,M . A l - M a s u m , a n d N . A s a . . / 3V. G a u t h i e r ,C . G r a n d j e a n ,B . C a z e s ,a n d J . ( "Y. U c h i m a r u , A . M . M . E l S a y e d ,a n d M . T e r 'uB. M. Trosr and Y. Shi, "/ACS ll5, 9421 ( l9{)l "S.-K. K a n g , D . - C . P a r k , C . - H . P a r k , a n d R .- l ttJ. Ji and X. Lu, CC 764 (lgg3). 'nH. Nakamura, N. Sadayori, M. Sekido. eod Y *N. C. Ihle and C. H. Heathcock. JOC St. ffi
Tris(dimethylamino)sulfur trimcthybill p-Keto sulfoxides.t TAS-F prornorc S-aryl arenethiosulfonate .S-oxides. 'R.
Caputo, C. Ferreri, L. Longobardo. G hh
Tris(pentaf luorophenyl)boranc. Aldol and Michael reactions. (Cfrl lyst for these reactions.Thus the aldol cood aldehyde can be conducted at -78"C.' Agl
The analogouscondensationwith imines p Epoxide rearrangement.a With rhe t favored during the rearrangement.
o
oA" Ar3&Phlb.6f SbF/Pht e. -7f
Tris(pentafluorophenyl)borane 393
of ring formar.i. r t(rnsequences rc:lcJ. o{,e I
- - .1
77"/o
l r : , n , \ f a l l y l i c c a r b o n a t e s roTc c u r s 8,, r.()merizationand dehydration, .,(-arboranyltributyltinadds to The Pd versionof f.':nr carbinols.rn in the presenceof CO, rrr.;.lr.hable tr r 1)ne-stePconstruction of d'-
'tS. Okamoto, N. ono, K. Tani, Y. Yoshida, and F. Sato, CC 2'19(1994). 'tJ.P. G e n e t , E . B l a r t , M . S a v i g n a c ,S . L e m e u n e ,S . L e m e u n e - A u d o i r e ,a n d J . M . B a r n a r d , S L 680 0993). 20V. Farina, B. Krishnan, D. R. Marshall, and G. P. Roth, JOC 5E, 5434 (1993). 2rL. S . L i e b e s k i n d a n d S . W . R i e s i n g e r ,J O C 5 E , 4 0 8 ( 1 9 9 3 ) . "D. B a d o n e ,R . C a r d a m o n e ,a n d U . G u z z i , T L 3 5 , 5 4 7 7 ( 1 9 9 4 ) . " R. s. Paley and A. de Dios, It 34,2429 (1993). 2aB. H . L i p s h u t z a n d A . A l a m i , T t 3 4 , 1 4 3 3( 1 9 9 3 ) . "S. Casson and P. Kocienski, JCS(PI) ll87 (1993). 26M. S . D e s h p a n d e ,T L 3 5 , 5 6 1 3 ( 1 9 9 4 ) . "N. Y a s u d a ,L . X a v i e r , D . L . R i e g e r , Y . L i , A . E . D e C a m p , a n d U . - H . D o l l i n g , T L 3 4 , 3 2 l l ( I993). ttT. Gillmann and T. Weeber, 5L649 (1994). 2eM. C a t e l l a n i , G . P . C h i u s o l i , M . C . F a g n o l a ,a n d G . S o l a r i , Z L 3 5 , 5 9 1 9 ( 1 9 9 4 ) . 'oK. K o n d o , M . S o d e o k a ,M . M o r i , a n d M . S h i b a s a k i ,S 9 2 0 ( 1 9 9 3 ) . rl B. M. Trost and J. Dumas, TL 34, 19 (1993). 12H. Nemoto, Y. Kubota. and Y. Yamamoto, CC 1665 (1994). "Y. Y a m a m o t o ,M . A l - M a s u m , a n d N . A s a o , , / A C Sf 1 6 , 6 0 1 9 ( 1 9 9 4 ) . 3aV. Gauthier, C. Grandjean, B. Cazes, and J. Gore, BSCF 131, 381 (1994). "Y. U c h i m a r u , A . M . M . E l S a y e d ,a n d M . T a n a k a , O M 1 2 , 2 0 6 5 ( 1 9 9 3 ) . 'uB. M. Trost and Y. Shi, "|ACS 115, 9421 (1993\. ttS.-K. Kang, D.-C. Park, C.-H. Park, and R.-K. Hong, IL36,405 (1995). 38J. Ji and X. Lu. CC 764 (1993\. t'H. N a k a m u r a , N . S a d a y o r i ,M . S e k i d o ,a n d Y . Y a m a m o t o , C C 2 5 8 l ( 1 9 9 4 ) . nuN. C . I h l e a n d C . H . H e a t h c o c k ,J O C 5 8 , 5 6 0 ( 1 9 9 3 ) .
Tris(dimethylamino)sulfur trimethylsilyldifluoride (TAS-F). 13,336:15, 355 p-Keto sultoxides.t TAS-F promotesthe sulfinylationof silyl enol etherswith ,5-arylarenethiosulfonate S-oxides. 'R. r\.)11
t:
/ r r r 5 9 .8 1 0 7( 1 9 9 4 ) . ( ( l : . 1 2 3( 1 9 9 3 ) . l
'- i
I
r ' : , : t . J O C5 8 , 1 5 3 8( 1 9 9 3 ) . ) r - - : ' r L r . a n d S . T o r i i ,J O C 5 9 , 3 0 4 0 |
.
qa i I
Tris(pentaf luorophenyl)borane. Aldol and Michael reactions. (CuFs)3Bis an air-stable and water-tolerantcatalyst for these reactions.Thus the aldol condensationbetween a silyl enol ether and an aldehyde can be conducted at -78'C.rAqueous HCHO can be used as electrophile.2 The analogouscondensationwith imines provides a route to p-amino esters.l Epoxide rearrangemenL4 With the borane in nonpolar solvents,alkyl shift is favored during the rearrangement.
\. de Meijere, and J. Salaun, IL
rrri -::
C a p u t o , C . F e r r e r i , L . L o n g o b a r d o ,G . P a l u m b o , a n d S . P e d a t e l l a ,S C 2 3 , l 5 l 5 ( 1 9 9 3 ) .
. e9-l).
?-, ... OM 12, l42g(lgg3). :^ - 1993).
| -".,.
o
o
r'Y\ t l
cHo Bu
Bu Ar3B/PhMe,600 SbFs/PhMe,-78o
'.
/'Y^eu t l
98
2
t5
oc
394 Tungsten Pentacarbonyl 'K. Ishihara,N. Hanaki, and H. Yamamoto' SL 577 (1993)' l72l (1995). K . I s h i h a r a , N . H a n a k i , M . F u n a h a s h i ,M . M i y a t a , a n d H . Y a m a m o t o ,B C S . I6 8 , ( 1 994). ,K. 9 6 3 S l Y a m a m o t o , I s h i h a r a , M . F u n a h a s h i ,N . H a n a k i , M . M i y a t a , a n d H . oK. ( 1 9 9 5 ) ' 7 2 1 S L Y a m a m o t o , I s h i h a r a ,N . H a n a k i , a n d H ' ,
Tris(trimethylsilyl)silane. 15, 358-359; 16' 374-3'15 by a Alkanesfrom alcohols.t RoH is deoxygenatedvia the thioxocarbamates benzene' in refluxing (MerSi):SiH-AIBN free radical reaction with Ketone synthesis.2 The assemblyof RCOCHzCH2R from RI, CO' and electrondeficientalkenesCHr:611p' is mediatedby (MerSi)rSiH-AIBN' 'M. ObaandK. Nishiyama'250, 10193(1994)' '1. Ryu, M. Hasegawa, A. Kurihara,A. Ogawa'S' Tsunoi,andN' Sonoda'sL 143(1993)'
Trityl chloride. 15, 359-360 Polyols form monotrityl ethers with limited amount Selective O-alkylation.r (10 mol vo) of TrCl and pyridine. A primary hydroxyl is favored over a secondary derivatized. alcohol, and only one of the two primary hydroxyl groups of a diol is sc 24'2399 'v. E. M. Kaats-Richters, andL.w. Jenneskens, J.w. Zwikker,E. M. D. Keegstra, (1994).
Tritylperchlorate.13'339-340;14,344-345;15'361-362;16'375-376 r Unusual chemoselectivity is revealedusing trityl ethers as glyGlycosylation In this cosyl acceptors.secondary ROTr have higher reactivity than primary ethers. reaction, TrCIO+ acts as a catalyst.
?Poo"
?Poo. AcoSi\
+
Bno
rrcro4 n"o$-!,61,
cHd
o.?"o_$fl
*,,,,("
Bnodu" s4yo
ry.
(1993). E . T s v e t k o v ,p . I . K i t o v , L . v . B a c k i n o w s k y ,a n d N . K . K o c h e t k o v , T L 3 4 , 7 9 ' 1 7
Tungsten pentacarbonyl.14, 345-346 pauson-Khand reaction.t The w(co)s . THF complexpromotesformationof from 1,6-enynes. bicyclicdienones 'T. R. HoyeandJ.A. Suriano, (1993)' 115'1154 "/ACS
Ultrasound. 15, 363; 16' 37'7-3'19 Reduction of esters't Primarl akot gllcol-{ tion with the NaBHn-Polyethylene t triacthylsilyl of Reductive coupling tl b} yield 89'9% in (Me3Si), is formed tlr biphenyl as an electron-transferagent' r 1,4-cyclohexadrr 3,6-bistrimethylsilylL'hn cyanidcs"' alkyl of Alkylation all'ots t of nitriles with Na in toluene and hYdroxYu and HYdrostannYlation ts organotin hydride to a multiple trcnd p-hldrot a is product presenceof air. the Wittig rcactions.s Vinylic chakoirr tions using KzCOr as base' Carbene formation'b DecomPosrt which are intercePtedbY alkcnes' Diels- Alder reaction of l- azalieut ily synthesizedin high Yields'
'H. Liu, x.-L. Ji, andK. Huang'l't' 13'{:l tE. A. MistrYukov, MC 251(1993)' rJ. Berlan,H. Delmas,I' Duee'J' L' Luch' t oE. Nakamura, Y' Imanishi,andD' Mrhtt' 5C.C. Silveira,G. Perin,andA' L' Bnge' l( uA. K. BertramandM'T' H' Liu' CC {6i ' lq 'M. Villacampa'J.M' Perez,C Avcndeoot
1,": o i i l \ a m a m o t o , B C S J 6 3 '1 7 2 1( 1 9 9 5 ) ' r : ; l l Y a m a m o t o ,S t 9 6 3 ( 1 9 9 4 ) ' l9e
rl
55%
. .t( , Pl) 277(1994).
Tclopropanes.r In conjunction with dir.Jldnt removesone bromine atom in a H F,,'mplex gives IV2Clr(thf)c]z(ZnzClc) l c r r J e s f u r n i s h e ss y n - 1 , 2 - d i o l s .
Aldehydes are attacked by the selenium ylides derived Epoxide formation.t from the cation.The B-selenoniumoxide intermediatesdecomposeby selenideelimination, resultingin epoxideproducts. rY. Watanabe, Y. Ueno,and T. Toru, BCSJ66, 2042(1993).
e-: I Ikeda,IOC 58, 6529(1993). I vqi r A.W. Konradi,S.J. Kemp,andS.F.
Vinylzinc reagents. Preparation. These reagentsare accessiblefrom vinyl halides by reaction with the metal,r or by transmetallationof vinyl derivativesof tin (via lithium),2 zirco-
z : r . , r n i a .v a n a d i u m ( V )o x i d e i s u s e di n sr' rrnt (e.g., CH2CI2)to give aldehydes
nium,3and boron.o Coupling with vinylic iodides,t'2 Formation of conjugated dienes is caralyz'ed by Pd(0) speciesat room temperature. Allylic alcohols.3 Alkenylzirconocenes derived from alkynes are converted into the zinc reagents(with MezZn at -65'), which reactwith aldehydes.
L
-r-
199.1).
'R. Rossi,A. Carpita,F. Bellina,and P. Cossi,JOMC451,33(1993). 2B.H. Lipshutz,M. Alami, andR. B. Susfalk,SL 693 (1993). tP. wipf andW. Xu, TL 35,5197(1994). 'K. A. AgriosandM. Srebnik,JOMC444, l5 (1993);idem.,JOC59, 5468(1994).
c,.r:rplexis a catalyslfor aerial oxidation
l q ! :
Vitamin B12-zinc. Ring cleavage.r Cyclopropanesare isomerized to give chiral alkenes.
398
Vitamin Blazinc
o \\^
ar^.V u Fd'
o
vitamin-B12 / Zn NHICI/ THF rt.2h
o \-o
a)< Y' \:t >-d
o
87"/" (81"/" ee\ rT.
,l994't. Troxler and R. Scheffold. HCA 77. ll93
Water. 16, 383 Waterhasbeenusedas a solvent.n Thesc rt and pressures. temperatures elimination.rte hydrolysis, processes: 'B.
K u h l m a n n ,E . M . A r n e t t , a n d l l
Srsr
o /-or., X
Fd'
o
87q" (81% ee)
Water. 16, 383 reactions at high water has been used as a solvent, reagent,or catalyst for organic base-catalyzed or acidtypically temperatures and pressures.These reactions are etc'' proaarra., hydrolysis, elimination, rearrangements, ' B . K u h l m a n nE, . M . A r n e t t ,a n dM . S i s k i nJ' O C 5 9 , 3 0 9 8( 1 9 9 4 ) '
Xenon(II) fluoride. 13, 345 afford Fluorination ofaromatic compounds. Phenolsrand pyrrole derivatives2 XeF2. with fluorinated products on reaction Fluorodemetallation. Replacementof silyl and stannyl substituentsfrom arylin the silanes3and B-trialkylstannyl enonesois rapid. The latter reaction is effected presenceof AgOTf as catalyst. Fluoroselenylation.s The combination of XeF2 with RzSezor RSeSiR: delivers the RSe/F groups to alkynes in the tans fashion' a,at-Diphenylperfluoroalkanes.6 The treatment of an n-perfluoroalkanedicarto boxylic acid and benzene with XeFz in cHzclz at room temperature is sufficient 41-65Vo). (3 examples, moderate bring about the transformation. Yields are Fluorinated methyl aryl ethers. The facile rearrangementof oxygenatedbenzyl to derivativeseffected by XeFz to give fluorinated methyl ethers,i.e., benzyl alcohols inmay ethers'E aryl to difluoromethyl fluoromethyl aryl ethersTand benzaldehydes ions' volve the formation of fluoroxy intermediates and thence oxaspirobenzenium
Ytterbium. 14,348;15, 336: t5. l Reduction of sulfur co;181 ytterbium and disulfides is catal;conjugate addition to enonesDiaryl thioketones are rcd$c(
desulfurized Products. Reductive couPling of Lcta both saturated and conjugated k4
respectivelY. Silyl ketones behave different a-silyl alcohols, aromatic congc Melsicl, the PurPorted oxaYttctl another PathwaYaPPearswhcn tb
ketone. A tandem deoxYgenatno donating the acYl moieties.r
o'.-F XeF2l QH2CI2
.o
R = H,2-NOz,3-F,4-CFg
75 - 85"/"
Ph