Mechanism of Formation of α,β-Unsaturated Esters in the Reaction of Ethyl Mercaptoacetate Dianion with Carbonyl Compounds

Abstract

Abstract Dianion derived from ethyl mercaptoacetate undergoes aldol type reaction with a carbonyl compound to give an adduct, which exhibited low diastereoselectivity. However, the adducts obtained by the reaction with a variety of aldehydes were subsequently treated with ethyl chloroformate in the presence of trivalent phosphorus compound to give (E)-isomers of α,β-unsaturated esters in high yields with greater than 85% stereoselectivity regardless of the stereochemistry of the diastereomers of the adducts. The stereochemical mechanism and application of this reaction were studied in detail.