Figure 11.

Mechanism of radical trifluoromethylation. •OH is formed by laser photolysis of HO-OH (pathway a), followed by •OH oxidation of CF₃SO₂₋ to form the reactive intermediate CF₃SO₂•, which generates •CF₃ via entropy-driven loss of SO₂. The electron-deficient •CF₃ readily adds to proteins (pathway b). In alternatively minor pathway c, HO• directly abstracts H• from the protein to produce a protein radical that either couples with •CF₃ to provide a CF₃-modified product or reacts with HO• to generate oxygen-containing products.