Asymmetric hydrogenation of prochiral alkenes catalysed by ruthenium complexes of (R)-(+)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl

Abstract

Two chiral ruthenium(II) complexes containing (R)-(+)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl[(R)-BINAP] were found to be effective catalysts for the asymmetric hydrogenation of 2-acylaminoacrylic and 2-acylaminocinnamic acids under mild conditions, to afford N-acyl-(R)-α-amino acids with 49–95% optical purity. The differences between the asymmetric hydrogenations effected by Ru^II- and Rh^I-(R)-BINAP systems are discussed. Asymmetric hydrogenation of methylenesuccinic acid and its derivatives with Ru-(R)-BINAP is also described.