Electrophotocatalytic Radical Cascade Reaction for the Synthesis of Trifluoromethylated Spirocyclobutyl Oxindoles

We report an electrophotocatalytic strategy for the radical fluoroalkylation and spirocyclization of bicyclo[1.1.0]butanes. 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.