PhSO₂CF₂H as a difluoromethylene bridge connecting electrophiles and electronically diverse alkenes

The difluoromethylene (-CF₂-) motif is highly valuable in pharmaceuticals, agrochemicals, and materials science due to its unique physicochemical properties. Herein, we present a broadly applicable strategy for the modular synthesis of CF₂-containing compounds by using difluoromethylene to bridge electrophiles and electronically diverse alkenes, with difluoromethyl phenyl sulfone (PhSO₂CF₂H) as the difluoromethylene source. Central to this approach is the activation of (phenylsulfonyl)difluoromethylated derivatives (PhSO₂CF₂R) by the excited-state Hantzsch ester anion (HE^-), which enables efficient generation of difluoroalkyl radicals under mild conditions. This method exhibits broad substrate scope, accommodating electron-rich, neutral, and deficient alkenes, as well as a wide range of difluoroalkyl sulfones derived from alkyl halides, cyclic sulfates, and carbonyl compounds. Furthermore, we developed a simplified operational protocol that circumvents the need for pre-preparation of PhSO₂CF₂R. Mechanistic studies support a radical pathway initiated by single-electron transfer between the photoexcited HE^- and PhSO₂CF₂R. Practical applications are demonstrated through gram-scale syntheses and late-stage modification of bioactive molecules and functional materials, establishing a versatile platform for constructing a wide range of difluoromethylene-containing compounds.