Transfer Hydrogenation of Carbonyl Compounds Catalyzed by a Ruthenium−Acetamido Complex:  Evidence for a Stepwise Hydrogen Transfer Mechanism

The ruthenium−acetamido complex, prepared from the reaction of [(PCy₃)₂(CO)(CH₃CN)₂RuH]⁺BF₄^- with KOH in 2-propanol, was found to be an effective catalyst for the transfer hydrogenation of carbonyl compounds and imines. Observation of both the inverse deuterium isotope effect and the competitive inhibition by added phosphine provided strong evidence for a stepwise mechanism of proton and hydride transfer via a coordinatively unsaturated ruthenium−amido species.