Cobalt-Mediated Direct Carbon-Hydrogen Bond Functionalizations

Transition-metal-catalyzed direct C-H bond functionalizations have attracted considerable attention around the world for almost half a century. In the past decades, great efforts have been made for the development of late transition metals, mainly due to some advantages in terms of the diversity and high efficiency of the catalysts. However, their application was limited on account of their relatively high price, low natural abundance and partly strong toxicity. Cobalt as compared to precious transition metals has shown great potential in the C-H bond functionalizations because of its low cost, unique reactivity profiles and easy availibility in the earth’s crust. This review provides recent advances in direct C-H bond functionalizations mediated by cobalt from C-C and Cheteroatom bond forming reactions.