Synthesis of Alkoxymethylene and Alkoxycarbonyl-oxymethylene Butyrolactones

Abstract

A previously published route to α-alkoxymethylenebutyrolactones has been shown to yield instead the corresponding carbonates. An alternative synthesis of the (E)-alkoxymethylene derivatives is described along with details of photoisomerisation to yield mixtures from which the (Z)-alkoxymethylene lactones can be obtained readily by chromatography.