DIPHOSPHONITES AS HIGHLY EFFICIENT LIGANDS FOR ENANTIOSELECTIVE RHODINM-CATALYZED HYDROGENATION

Chiral ligands with achiral backbones such as ethano- or ferroceno-bri dges linking two phosphonites derived from chiral diols such as binaph thol (BINOL) have been prepared; the corresponding Rh complexes are ex cellent catalysts in the hydrogenation of prochiral olefins such as it aconic acid dimethyl eater or 2-acetamido methyl acrylate, the ee valu es being 90-99.5%.