Reductive Arylation of Arylidene Malonates Using Photoredox Catalysis

A strategy with arylidene malonates provides access to β-umpolung single-electron species. Reported here is the utilization of these operators in intermolecular radical–radical arylations, while avoiding conjugate addition/dimerization reactivity that is commonly encountered in enone-based photoredox chemistry. This reactivity relies on tertiary amines that serve to both activate the arylidene malonate for single-electron reduction by a proton-coupled electron transfer mechanism as well as serve as a terminal reductant. This photoredox catalysis pathway demonstrates the versatility of stabilized radicals for unique bond-forming reactions.