A Novel Synthesis of γ,δ‐Unsaturated Aldehydes from α‐Formyl‐γ‐lactones

A preparatively useful one-step transformation of γ,γ-disubstituted α-formyl-γ-lactones into trisubstituted γ,δ-unsaturated aldehydes is described, by means of catalytic amounts of either AcOH or AcOEt in the vapor phase over a glass support. A mechanistic rationale is proposed.