Synthesis of the first gold(I) carbene complex with a gold-oxygen bond first catalytic application of gold(I) complexes bearing N-heterocyclic carbenes

A series of silver(I) and gold(I) carbene complexes of the type [Ag(R-2-imy)(2)](+)[AgBr2](-) and [Au(R-2-imy)X] (R-2-imy = 1-diphenylmethyl-3-methyl-imidazol-2-ylidene; X = Cl, OC(O)CH3) have been prepared and structurally characterized. The complex [Au(R-2-imy) OC(O)CH3] is the first gold(I) carbene complex with a gold-oxygen bond. The results of a single crystal structure determination of this gold(l) carbene acetate are similar to those of the analogous (triphenylphosphane)gold(I) acetate. The gold oxygen distance Au-O1 with 2.040(4) Angstrom parallels the majority of (phosphane)gold(I) carboxylates. Furthermore we successfully employed the Au(I) carbene acetate as a catalyst for the addition of water to 3-hexyne in the presence of a Lewis acid as co-catalyst. This is the first example for the use of a gold(I) carbene complex in homogeneous catalysis.