Efficient synthesis of ruthenium vinyl carbene complexes

First generation Grubbs catalyst [RuCl2(PCy3)2(double bond; length as m-dashCHPh)] and related complexes of a general formula [RuCl2(PCy3)2(double bond; length as m-dashCHR)], where R is an aromatic or methyl group, undergo efficient reaction with trimethylsilylacetylene and related silylacetylenes to form vinyl carbene complexes [RuCl2(PCy3)2(double bond; length as m-dashCHCHdouble bond; length as m-dashCHR)] and disiloxane. The reaction requires the presence of water in the reaction medium. It is a convenient method for the high-yield synthesis of ruthenium vinyl carbene complexes. For benzylidene complexes, the reaction gives exclusively E-geometry of vinyl carbene ligand.