<i>gem</i> ‐Difluorinated Phosphonium Salts as Sources of Difluoroalkyl Radicals

The advent of photoredox catalysis established difluorinated phosphonium salts as the valuable type of difluoroalkyl radical sources that stand out from the row of fluoroalkylative reagents. The synthetic application of this class of compounds varies from simple, yet robust and universal photoinduced difluoromethylation to assembling rather complex difluorinated frameworks. This review summarizes the radical difluoroalkylation reactions, which utilize difluorinated phosphonium salts employed as reagents or intermediate compounds from the first report in 2015.