A general stereospecific synthesis of γ-hydroxy-α,β-unsaturated esters

Article abstract of DOI:10.1016/S0040-4039(00)97124-7

A stereospecific synthesis of optically active γ-hydroxy-α,β-unsaturated esters is achieved, involving successively the Sharpless epoxidation of allylic alcohols, oxidation to glycidic acids, conversion into α,β-epoxy diazomethyl ketones, and irradiation in ethanol at 300 nm. Intermediates in the photo-induced rearrangement are epoxy ketenes, which undergo ethanolysis with simultaneous opening of the epoxide, preferably via a transition state involving the s-trans conformation.