Michael additions of the lithium enolates of α-heterosubstituted esters and amides to a chiral α,β-unsaturated carbonyl acceptor, ethyl ( E-3-[( S)-2,2-Dimethyl-1,3-dioxolan-4-yl]propenoate. High stereoselection and chiral induction

Abstract

α-Heterosubstituted esters and amides, after lithiation with LDA in THF at −78 °C, undergo highly syn- or anti-selective Michael additions to ethyl (E)-3-[(S)-2,2-dimethyl-1,3-dioxolan-4-yl]-propenoate, while similar reactions of acetamide and propanamide are poor in selectivity.