Abstract
Asymmetric hydrogenation of α-amino-β-keto esters using ruthenium (Ru), rhodium (Rh), and iridium (Ir)-chiral phosphine catalysts proceeds anti-selectively through dynamic kinetic resolution to afford anti-β-hydroxy-α-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.
