A One‐Pot Synthesis of α,β‐Unsaturated Esters From Esters

Abstract

A convenient method for reductive Horner–Wadsworth–Emmons (HWE) olefination is described. The E‐selective HWE homologation of various esters to α,β‐unsaturated esters was readily achieved and gave the desired products in good‐to‐moderate yields under mild conditions. The one‐pot reaction proceeds through an in situ generated aldehyde, formed via the partial reduction of an ester with lithium diisobutyl‐t‐butoxyaluminum hydride. The formation of cyclized metal acetal and subsequent decompose to the aldehyde for the olefination was found to be a crucial step in this C2‐carbon homologation protocol.