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.