Cobalt/Photoredox Cooperative Catalysis‐Enabled Cycloaddition Reactions of 1,6‐Diynes and Related Compounds

Abstract

AbstractCobalt catalysts have recently gained considerable attention as alternatives to catalysts based on precious transition metals such as Rh and Ir. Recently, Co/photoredox cooperative catalysis has emerged as a powerful tool that enables versatile transformations, including cycloaddition reactions of unsaturated compounds. In particular, 1,6‐diyne derivatives are fascinating substrates for these reactions because the corresponding exocyclic 1,3‐diene products can be further transformed into sp3‐rich carbocycles and heterocycles via functionalization of the diene moiety. The dual catalytic system can facilitate not only the cycloaddition based on the activation of the π‐bond only, such as alkyne cyclotrimerization, but also the cycloaddition involving σ‐bond activation. This Concept highlights the recent advances in Co/photoredox cooperative‐catalysis‐enabled cycloaddition reactions, focusing on the reactions of 1,6‐diyne substrates, which are difficult to perform when well‐defined cationic CoI catalysis is employed.