Photocatalyst‐Free Hydrodifluoromethylation of Alkenes via Thiol‐Mediated Photoactivation of Zn(CF 2 H) 2 (DMPU) 2

Abstract

Herein, we report a photocatalyst‐free hydrodifluoromethylation of alkenes using Zn(CF 2 H) 2 (DMPU) 2 and thiophenols under 390 nm irradiation. The thiophenol serves a dual stoichiometric function, promoting the formation of a photoactive thiol‐modified organozinc species while acting as the terminal hydrogen‐atom donor. The reaction is applicable to styrenes, electron‐rich and electron‐deficient alkenes, and 1,1‐disubstituted alkenes, as well as selected internal and unactivated aliphatic alkenes. Its synthetic utility is further demonstrated by the late‐stage difluoromethylation of biologically relevant molecules. Preliminary mechanistic investigations, including radical‐clock experiments, spectroscopic analysis, and 19 F NMR experiments, support a radical pathway involving thiophenol‐induced speciation and photoactivation of the organozinc reagent, followed by hydrogen‐atom transfer to the resulting carbon‐centered radical. These findings establish thiophenol‐mediated photoactivation as a distinct strategy for exploiting Zn(CF 2 H) 2 (DMPU) 2 in radical difluoromethylation.