Synthesis of Hemilabile Cyclic (Alkyl)(amino)carbenes (CAACs) and Applications in Organometallic Chemistry

A versatile methodology, involving readily available starting materials, allows for the synthesis of stable hemilabile bidentate cyclic (alkyl)­(amino)­carbenes (CAACs) featuring alkene, ether, amine, imine, and phosphine functionalities. The stability of the free carbenes has been exploited for the synthesis of copper­(I) and gold­(I) complexes. It is shown that the pendant imine moiety stabilizes the gold­(III) oxidation state and enables the C–C bond oxidative addition of biphenylene to the corresponding cationic gold­(I) complex. The latter and the corresponding copper­(I) complex show high catalytic activity for the hydroarylation of α-methylstyrene with N,N-dimethylaniline, and the copper­(I) complex promotes the anti-Markovnikov hydrohydrazination of phenyl acetylene with high selectivity.