Asymmetric catalytic routes to chiral building blocks of medicinal interest

Asymmetric hydrogenation reactions can provide practical access to a diverse array of chiral building blocks. We have developed a variety of highly selective rhodium and ruthenium hydrogenation catalysts based on chiral 1,2-bis(phospholano)benzene (1; DuPHOS) and 1,2-bis(phospholano)ethane (2; BPE) ligands. The expanding utility of these catalyst systems is revealed through highly enantioselective syntheses of alpha-amino acids, beta-branched amino acids, and beta-hydroxy esters. The versatility of the catalysts derives from our ligand design which allows variation of the steric environment imposed by the phospholane Ligands such that they can accomodate the different steric demands of each substrate class of interest.