Z/E selective synthesis of beta,beta-disubstituted and (Z)-beta-monosubstituted Baylis-Hillman adducts via anionic additions of vinylcuprates to aldehydes
Hx. Wei et al., Z/E selective synthesis of beta,beta-disubstituted and (Z)-beta-monosubstituted Baylis-Hillman adducts via anionic additions of vinylcuprates to aldehydes, SYN COMMUN, 29(17), 1999, pp. 2959-2966
A new method has been developed for the synthesis of achiral beta,beta-disu
bstituted and (Z)-beta-monosubstituted Baylis-Hillman adducts with excellen
t Z/E stereospecificity in some cases. The process involves the conjugate a
dditions of R2CuLi or RMgBr-CuBr-DMS to alpha,beta-acetylenic esters and fo
llowed by additions of anionic alpha-(alkoxycarbonyl)vinyl]copper intermedi
ates to aldehydes. The individual Z- and E- isomers of the resulting beta-b
ranched alpha-(hydroxylalkyl)acrylates can be separated by column chromatog
raphy in modest to excellent yield.