Tandem Radical Cyclization for the Construction of Difluoro‐Containing Oxindoles and Quinoline‐2,4‐diones

Abstract Cu‐catalyzed direct difluoromethylation of activated alkenes through a difluoromethyl radical addition/cyclization to afford difluorinated oxindoles and quinoline‐2,4‐diones has been developed. This method provides convenient access to a variety of oxindoles and quinoline‐2,4‐diones under mild conditions via a proposed tandem radical cyclization process, while tolerating various functional groups well. Moreover, a facile method to construct diverse difluorinated quinoline‐2,4‐diones by visible‐light photoredox catalysis under mild conditions was presented.