Synthesis of α,β-unsaturated γ-lactones via photooxygenation of 2,3-dihydrofurans followed by ferrous ion-catalyzed gem-dehydration

Photooxygenation of 2,3-dihydrofurans in CCl4 at ambient temperature followed by ferrous ion-catalyzed gem-dehydration of the yielded allylic hydroperoxides afford the corresponding α,β-unsaturated γ-lactones in good to excellent yields.