Development of Homogeneous PNP-Ruthenium Complexes (Ru-MACHO Family) for Hydrogenation of Esters and Beyond

Development and applications of the Ru-MACHO family of ruthenium complexes are described. The parent Ru-MACHO was originally developed for catalytic reduction of esters by molecular hydrogen, which not only provides an environmentally benign and safe protocol, but also achieves a wide range of substrate scope. The reaction with methyl lactate was demonstrated on an industrial scale, producing 2,200 kg of 1,2-propanediol with high optical purity. In addition to hydrogenation of esters, the Ru-MACHO family catalyzes a variety of reactions, including hydrogenation of nitriles and sugars, dehydrogenation of alcohols, N-monomethylation of aromatic amines, and formal deoxygenative hydrogenation of lactams.