Stereoselective Enol Tosylation: Preparation of Trisubstituted α,β-Unsaturated Esters

Abstract

The stereoselective preparation of (E)- or (Z)-trisubstituted α,β-unsaturated esters in three steps from N-protected glycine is presented. The key step in the synthesis is the highly selective enol tosylation of γ-amino β-keto esters. The enol tosylates are stable, crystalline compounds that undergo smooth and effective Suzuki−Miyaura coupling reaction with a variety of aryl boronic acids.