Electrochemical Cycloaddition Reactions of Alkene Radical Cations: A Route toward Cyclopropanes and Cyclobutanes

Herein, we describe a mild and efficient electrochemicalmethod for cycloaddition reactions of alkene radicalcations. Anodic oxidation of olefins produces electrophilic alkeneradical cations, which further react with either diazo compounds ina [2 + 1] cycloaddition toward cyclopropane synthesis, or styrenederivatives in a [2 + 2] cycloaddition producing cyclobutanes. Bothprocesses are green, metal- and catalyst-free, and scalable andtolerate a broad range of electron-rich olefins.