Photocatalyst‐Free Visible‐Light Induced Radical Difluoromethylation/Cyclization Cascade Reaction for the Synthesis of Difluoromethylated Oxindoles with Difluoromethyl Phenoxathiinium Salt

Abstract A photocatalyst‐free photoinduced radical difluoromethylation approach for the convenient synthesis of difluoromethylated oxindoles from N ‐arylacrylamides with difluoromethyl phenoxathiinium salt (PT‐CF 2 H + BF 4 − ) was developed, this transformation involves radical difluoromethylation/cyclization cascade process and features photocatalyst‐free, mild reaction conditions, broad substrate scope and good functional groups tolerance. With this method, a wide variety of N ‐arylacrylamides were successfully converted to desired difluoromethylated oxindoles in good to excellent yields.