Photoactive Ni-Complexes in Metallaphotoredox Catalysis: A Successful Match in C–C Cross-Coupling Reactions

Abstract Nickel catalysis is a well-established and powerful tool for C–C cross-coupling reactions, and its versatility has expanded significantly over past decades by its combination with visible-light photocatalysis in metallaphotoredox chemistry. Photocatalysis enables the activation of traditionally inert substrates and turnover of the Ni catalyst through a single-electron transfer processes. In recent years, dual catalysis has been further empowered by photoactive Ni intermediates, which exhibit distinct reactivity profiles from their ground states and complement existing protocols. This short review focuses on the emergent subclass of metallaphotoredox catalysis in which the synergy of a photoactive Ni catalyst and a typical photocatalyst (e.g., a polypyridyl Ir complex) provide solutions to challenging C–C bond formation. 1 Introduction 2 Photoactive Nickel Complexes 3 HAT-Mediated C–C Cross-Coupling 4 Halofunctionalization of π-Systems 5 Photoelimination of an Aryl Radical 6 Conclusion