Reaction and subsequent transformation of anionic acetylide–carbene complexes using the Ph3PAu+ fragment

The metallated Fischer-type carbene complexes (CO)5MC(NMe2)CCLi (M = Cr, W) react with Ph3PAuNO3 to form the β-substituted products (CO)5MC(NMe2)CCAuPPh3. In solution these products isomerise by formal metal fragment exchange to furnish Ph3PAuC(=NMe2)CCM(CO)5. A preliminary kinetic investigation by means of 1H-NMR spectroscopy indicates an unusual and complicated reaction mechanism. Model DFT calculations predict small energy differences between the products before and after the metal fragment exchange.