Catalytic anti-Selective Asymmetric Hydrogenation of α-Amino-β-Keto Esters through Dynamic Kinetic Resolution

Asymmetric hydrogenation of alpha-amino-beta-keto esters using ruthenium (Ru), rhodium (Rh), and iridium (1r)-chiral phosphine catalysts proceeds anti-selectively through dynamic kinetic resolution to afford anti-beta-hydroxy-alpha-amino acids with high enantiomeric purity, which are important intermediates for the synthesis of medicines and natural products. The mechanistic investigation has revealed that the Ru-catalyzed asymmetric hydrogenation takes place through the hydrogenation of the double bond in the enol tautomer of the substrate and the Rh- and Ir-catalyzed asymmetric hydrogenations proceed through the reduction of the keto tautomer of the substrate.