Heterogeneous asymmetric reactions: Part 28. Efficient and practical method for the preparation of (R)- and (S)-α-hydroxy esters by the enantioselective heterogeneous catalytic hydrogenation of α-ketoesters

α-Ketoesters (1–11: MeCOCOOR1, R1=Me, Et, i-Pr, i-Bu, t-Bu, neo-pentil, and RCOCOOEt, R=i-Pr, i-Bu, t-Bu, Ph, PhCH2CH2) can be hydrogenated with high enantioselectivity under mild experimental conditions (0 °C and room temperature, H2 pressure 1–25 bar) on Pt-alumina catalyst modified with cinchona alkaloids. In this way α-hydroxy esters that are important building blocks in organic syntheses can be produced in high optical yield (>90%).