Coupling Photocatalysis and Substitution Chemistry to Expand and Normalize Redox-Active Halides

Photocatalysis can generate radicals in a controlled fashion and has become an important synthetic strategy. However, limitations due to the reducibility of alkyl halides prevent their broader implementation. Herein we explore the use of nucleophiles that can substitute the halide and serve as an electron capture motif that normalize the variable redox potentials across substrates. When used with photocatalysis, bench-stable, commercially available collidinium salts prove to be excellent radical precursors with a broad scope.

Automated summary

Photocatalysis is an important synthetic strategy that can generate radicals in a controlled fashion. However, the reducibility of alkyl halides limits their broader implementation. This study explores the use of nucleophiles as electron capture motifs to normalize the variable redox potentials across substrates, leading to the discovery of bench-stable, commercially available collidinium salts as excellent radical precursors with a broad scope.