ИСТИНА

N-heterocyclic carbenes (NHCs)[1] became widely used as powerful ligands for stabilization of reactive species,[2] as organocatalysts,[3] and as spectator ligands in transition metal catalysis.[4] Most of NHC-metal complexes known to date are derived from imidazolylidene 1 and imidazolinyliden 2 type carbenes. Last three years our group develops chemistry of 6- (3) and 7-membered (4) ring carbenes.[5] Carbenes 3 and 4 exhibit superior stereoelectronic properties in comparison with 1 and 2. Expansion of the ring leads to significant increase in donor strength and sterical stabilization. In this contribution we report our recent results on theoretical calculations of electronic structure and ligand properties of 3 and 4; efficient methods of synthesis of imidazolium salts and generation of free carbenes; synthesis of late transition metal (Cu, Ag, Au, Pd) complexes, and their utilization in stoichiometric and catalytic reactions. The most prominent results are: • free NHCs are oxidized by Cu(II) halogenides to give corresponding haloamidinium salts,[6] • cationic gold complexes are active catalysts of synthesis of indoles via heterocyclization of 2-alkynylanilines, • palladium complexes are highly active catalysts of Suzuki cross-coupling of hetaryl chlorides in aqueous media in presence of mild base.