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.