Direct H/OR and OR/OR′ Metathesis Pathways in Ester Hydrogenation and Transesterification by Milstein’s Catalyst

Using DFT calculations we identify a low-energy reaction path connecting methyl acetate and Milstein’s <i>trans</i>-[Ru­(H)₂(PNN)­(CO)] catalyst directly with acetaldehyde and <i>trans</i>-[Ru­(H)­(OMe)­(PNN)­(CO)]. The transformation represents a metathesis in which a hydride and an alkoxide are swapped between a metal center and an acyl group. The reaction leads to a simple mechanism systematically applicable to the diverse hydrogenation and dehydrogenative coupling chemistry that can be achieved by the given catalyst