ИСТИНА

N-heterocyclic carbenes (NHCs) became widely used as organocatalysts and as ligands in transition metal catalysis. Most of NHC-metal complexes known to date are derived from five-membered ring imidazol-2-ylidene and imidazolin-2-ylidene type carbenes. In recent years, our group develops chemistry of 6-, 7- and 8-membered ring carbenes. Expanded ring carbenes (er-NHCs) exhibit superior stereoelectronic properties in comparison with five-membered ring counterparts. Expansion of the ring leads to significant increase in donor strength and sterical hindrance. In this contribution we report our recent results on theoretical calculations of electronic structure and ligand properties of er-NHCs; efficient methods of synthesis of precursors and generation of free carbenes; synthesis of late transition metal (Cu, Ag, Au, Pd) complexes. It was found that er-NHC complexes of palladium are highly active in Suzuki-Miyaura coupling in water, and dimerization of terminal alkynes with formation of E-enynes. Cationic gold complexes are active catalysts of addition of nucleophiles to carbon-carbon triple bonds.