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

The sigma (sigma)-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 radicals is a continuing challenge within the synthetic community. Fluoromethylphosphonium salts are easily available, air- and thermally stable, as well as simple-to-handle. Herein, we report the ability of the sigma-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 trifluoromethylation of a variety of alkenes.

Automated summary

The sigma-hole effect is utilized to facilitate the photolysis of phosphonium iodide salts, selectively generating fluoromethyl radicals, allowing for mono-, di-, and trifluoromethylation reactions using fluoromethylphosphonium salts.