Nucleophilic Organocatalyst for Photochemical Carbon Radical Generation via S_N2 Substitution

Photochemical generation of radicals is a powerful way to construct various molecules. But most of these methods rely on initiators or the redox properties of radical precursors. Herein, we report a photochemical organic catalyst that reacts with benzyl halide to generate carbon radical via an S_N2 pathway. This nucleophilic catalyst can be easily prepared and is bench-stable. The S_N2 process does not rely on the redox properties of halides, showing potential synthetic utility. Control experiments and UV-vis spectroscopic analysis indicate that the S_N2 substitution adduct is the key intermediate.