Diastereo- and Enantioselective anti-Selective Hydrogenation of α-Amino-β-keto Ester Hydrochlorides and Related Compounds Using Transition-Metal-Chiral-Bisphosphine Catalysts.

This review describes our recent works on the diastereo- and enantioselective synthesis of anti-β-hydroxy-α-amino acid esters using transition-metal-chiral-bisphosphine catalysts. A variety of transition metals, namely ruthenium ( Ru), rhodium ( Rh), iridium ( Ir), and nickel ( Ni), in combination with chiral bisphosphines, worked well as catalysts for the direct anti-selective asymmetric hydrogenation of α-amino-β-keto ester hydrochlorides, yielding anti-β-hydroxy-α-amino acid esters via dynamic kinetic resolution ( DKR) in excellent yields and diastereo- and enantioselectivities. The Ru-catalyzed asymmetric hydrogenation of α-amino-β-ketoesters via DKR is the first example of generating anti-β-hydroxy-α-amino acids. Complexes of iridium and axially chiral bisphosphines catalyze an efficient asymmetric hydrogenation of α-amino-β-keto ester hydrochlorides via dynamic kinetic resolution. A homogeneous Ni-chiral-bisphosphine complex also catalyzes an efficient asymmetric hydrogenation of α-amino-β-keto ester hydrochlorides in an anti-selective manner. As a related process, the asymmetric hydrogenation of the configurationally stable substituted α-aminoketones using a Ni catalyst via DKR is also described. [ABSTRACT FROM AUTHOR]