Stereocontrol using a heterosubstituted allylic carbanion. Regio- and stereo-selective reactions of trimethylsilyl allylic carbanions with aldehydes

Abstract

Regio- and stereo-selective coupling between trimethylsilyl allyl carbanions and aldehydes is achieved in the presence of an additive, ‘M’; use of R₂BCl or EtAlCl₂ as the additive gives the threo isomer (3) predominantly, while use of Bu₃SnCl–BF₃ affords the erythro isomer exclusively.