Electrochemical Synthesis of γ-Lactones from the Intermolecular Oxidative Coupling between Malonates and Styrenes

We report a ferrocene-mediated electrochemical intermolecular oxidative annulation between malonates and styrenes that avoids the use of excess oxidants such as Mn(OAc)3. The reaction proceeds via presumably the generation of a malonyl radical that adds to the styrene. After further anodic oxidation, the resulting benzylic carbocation is intercepted by one of the esters to deliver the desired γ-lactones.