Phosphine-Mediated Reductive Condensation of γ-Acyloxy Butynoates: A Diversity Oriented Strategy for the Construction of Substituted Furans

Exposure of γ-acyloxy butynoates to stoichiometric quantities of triphenylphosphine results in reductive condensation to afford substituted furans, by way of allenic ester intermediates. As γ-acyloxy butynoates are readily obtained through condensation of ethyl propiolate with aldehydes followed by acylation, this method represents a powerful and mechanistically novel protocol for the convergent three-component construction of substituted furans.