Recent advances in transition-metal-catalyzed C-CN bond activations

C-C bond activation and cleavage have become more and more attractive in recent years for the great challenge of breaking C-C bonds and the great advantage of constructing new chemical bonds. Among them, the activation of inert C-CN bonds by transition metals has been widely investigated and a number of improvements have been achieved by many groups. This review mainly summarizes recent advances in this field, based on different kinds of reactions derived from C-CN bond activation, including cyanofunctionalization, cross coupling reactions and cyanation. Moreover, mechanistic studies involving transition-metal-catalyzed C-CN bond activation are also mentioned.