Fig. 1: Synthesis of gem-difluorides.

a Synthetic route to gem-difluorides and its bioisostere. b Previously developed difluoromethylene synthon. c Challenges for difluoromethylene radical anion synthon (diFRAS). d This work: PhSO2CF2H as diFRAS for modular synthesis of gem-difluorides with chemical complexity. FG functional group, LG leaving group, PG protecting group.