Photoredox‐Coupled F‐Nucleophilic Addition: Allylation of gem‐Difluoroalkenes

A novel strategy for the expedient construction of CF3‐embeded tertiary/quarternary carbon centers was developed by taking advantage of photoredox catalysis. Thanks to a key step of single‐electron oxidation, electron‐rich gem‐difluoroalkenes, which otherwise are essentially reluctant towards F‐nucleoplilic addition, now readily participate in this fluoroallylation reaction. Furthermore, this strategy provides an elegant example for the generation, as well as functionalization, of α‐CF3‐substituted benzylic radical intermediates using cheap and readily available starting materials. Finding a gem: The fluoroallylation of gem‐difluoroalkenes with inexpensive Et3N⋅3 HF and readily available allylsulfone has been developed. The photoredox‐coupled fluoride nucleophilic addition process, combined with the radical allylation allows expedient access to a large collection of functionalized homoallylic trifluoromethane derivatives under mild visible‐light‐induced conditions at room temperature.