Electrochemical fluoromethylation triggered lactonizations of alkenes under semi-aqueous conditions

An electrochemical difluoromethylation triggered lactonization of alkenes was developed for the first time. This protocol employs readily prepared CF₂HSO₂Na as the difluoromethylating reagent, affording unprecedented CF₂H-containing lactones in moderate yields. Moreover, with CF₃SO₂Na as the trifluoromethylating reagent, a wide array of CF₃-containing lactones were obtained under additional supporting electrolyte- and catalyst-free conditions.