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.