ASYMMETRIC CATALYTIC ROUTES TO CHIRAL BUILDING-BLOCKS OF MEDICINAL INTEREST

Asymmetric hydrogenation reactions can provide practical access to a d iverse 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(phosphol ano)ethane (2; BPE) ligands. The expanding utility of these catalyst s ystems is revealed through highly enantioselective syntheses of alpha- amino acids, beta-branched amino acids, and beta-hydroxy esters. The v ersatility of the catalysts derives from our ligand design which allow s variation of the steric environment imposed by the phospholane Ligan ds such that they can accomodate the different steric demands of each substrate class of interest.