Cyclic (monoamino)carbene ligand-promoted metal catalysis

Cyclic (monoamino)carbenes, including cyclic (alkyl)(amino)carbenes (CAACs) and cyclic (amino)(aryl)carbenes (CAArCs), have been developed as ancillary ligands, mainly by taking advantage of their unique electronic properties such as strong nucleophilicity and electrophilicity in enhancing the reactivity of metals in organic transformations. This review focuses on the summary of recent developments by the use of CAACs and CAArCs as ligands in transition metal catalysis. It is organized by organic reactions that are promoted by CAAC- or CAArC-supported metal catalysis. A broad range of catalytic transformations that are promoted by CAAC-/CAArC-metal catalysis, including α-arylation of ketones, Mizoroki-Heck and Suzuki-Miyaura cross-coupling, Friedel-Crafts reaction, aerobic oxidation of aldehydes, hydrogenation of arenes and heteroarenes, functionalization of unsaturated C≡C, C=C, and C=X bonds, and olefin metathesis reactions, will be surveyed from the viewpoint of synthetic chemistry, mainly focusing on the discussion of the related reaction scope and catalytic mechanism for insight into the discovery of new transformations using these electron-rich carbene ligands.