An allenylidene Au() catalyst derived from triazole units and its initial application

An allenylidene Au( i ) catalyst based on triazolylidene moieties, featuring the high σ-donating ability (comparable to that of other NHC ligands) and largely enhanced π-accepting ability of its ligand, was developed for the first time. As compared with the extant gold complexes such as IPrAuCl, Ph 3 PAuCl and (PhO) 3 PAuCl, these allenylidene Au( i ) catalysts exhibited superior catalytic activities in the gold-catalyzed Nazarov reaction of aryl enones. First example of allenylidene Au( i ) catalyst, based upon alkynyl triazole unit, was developed and utilized in Au( i ) mediated Nazarov reaction.