At the heart of Noyori asymmetric hydrogenation are chiral ruthenium catalysts, often complexed with chiral diphosphine ligands such as BINAP (2,2'-bis(diphenylphosphino)-1,1'-binaphthyl). These catalysts facilitate the transfer of hydrogen from a donor molecule, typically H2, to the substrate in an enantioselective manner.
The general mechanism involves: 1. Coordination of the substrate to the metal center. 2. Oxidative addition of hydrogen. 3. Insertion of the substrate into the metal-hydrogen bond. 4. Reductive elimination to release the product and regenerate the catalyst.
