The Developing Concept of Bifunctional Catalysis with Transition Metal N-Heterocyclic Carbene Complexes

Though N-heterocyclic carbenes (NHCs) have long become popular as ligands of choice in transition metal mediated homogeneous catalysis, their related utility in bifunctional catalysis remains surprisingly overlooked. Conceptually more challenging, the bifunctional catalysis requires synchronous activations of substrates at complementary active-sites of a carefully crafted catalyst architecture, and which has been successfully realized in a number of interesting NHC-based bifucntional catalysts in recent times. The microreview summarizes the latest developments of this emerging area of the NHC-based bifunctional catalysis by looking into the underlying commonality existing behind these catalytic transformations from a mechanistic perspective.