Visible-Light-Induced Selective Photolysis of Phosphonium Iodide Salts for Monofluoromethylations

The sigma (σ)-hole effect has emerged as a promising tool to construct novel architectures endowed with new properties. A simple yet effective strategy for the generation of monofluoromethyl radical is a continuing challenge within the synthetic community. Flu-oromethylphosphonium salts are easily available, air- and thermally-stable, as well as simple-to-handle. Herein, we report the ability of σ-hole effect to facilitate the visible light-triggered photolysis of phosphonium iodide salts, a charge transfer complex, selectively giving fluoromethyl radicals. The usefulness and versatility of this new protocol are demonstrated through the mono-, di-, and trifluoro-methylation of a variety of alkenes.