Diels–Alder Reactions of 1,1-Bis(methylthio)ethene with Pyran-2-ones.

Abstract

Bis(methylthio)ethene has been shown to undergo Diels–Alder cycloaddition reactions with a range of simple and aryl-fused pyran-2-ones. These reactions can be brought about under either high-temperature or high-pressure conditions. These reactions are all regiospecific and in each case only a single product is isolated, either the initial bridged adduct or an aromatized product generated through decarboxylation. Although this dienophile is less reactive than the corresponding oxygen analogue it is still possible for cycloaddition chemistry to compete effectively with decarboxylation chemistry.