The Key Concepts and Strategy in Photoredox/Nickel Dual Catalysis and Application to C–C Bond Formation Reactions

Trisubstituted enones are versatile synthetic building blocks used for the synthesis of natural products and pharmaceutical agents. Various methods such as aldol reactions, olefination, cross-coupling, Heck reactions, and the organometallic-reagent additions have been developed to synthesize trisubstituted enones. However, these approaches are relatively inefficient in the aspects of atom and step economy. Recently, visible light photoredox catalysis has been recognized as a powerful synthetic tool. This method has been shown to photocatalytically generate chlorine atoms. The generation of alkyl radicals via hydrogen atom transfer (HAT) by halogen radicals and their addition to transition metals have enabled the selective intermolecular addition of nucleophilic radicals to alkynes.