In this review, we summarise the recent applications of pyridinium salts in radical-mediated difunctionalization of alkenes. Pyridinium salts are a privileged class of compounds that show great utility in natural...

The direct monofluoroalkenylation of C(sp3)–H bonds is of great importance and quite challenging. Current methods have been restricted to the monofluoroalkenylation of activated C(sp3)–H bonds. Here, we reported the photocatalyzed C(sp3)–H monofluoroalkenylation of inactivated C(sp3)–H bonds with gem-difluoroalkenes via 1,5-hydrogen atom transfer. This process shows good functional group tolerance, such as halides (F, Cl), nitrile, sulfone, ester, and pyridine, and good γ-selectivity. Moreover, this method succeeds in the photocatalyzed gem-difluoroallylation of inactivated C(sp3)–H with α-trifluoromethyl alkenes.