Electrophotocatalytic Radical Cascade Reaction for the Synthesis of Trifluoromethylated Spirocyclobutyl Oxindoles

We report an electrophotocatalytic strategy for the radical fluoroalkylation and spirocyclization of bicyclo1.1.0butanes. This synergistic method leverages the energy of electricity and light to generate fluoroalkyl radicals from inexpensive Langlois' reagents under mild, metal-free conditions. Overcoming the limitations of conventional electrochemistry and photoredox catalysis, this protocol provides efficient access to a diverse array of valuable spirocyclobutyl oxindoles bearing CF3, CF2H, and long-chain perfluoroalkyl groups with high functional group tolerance. Mechanistic studies confirm the radical cascade pathway and the essential role of the electrophotocatalytic system.