Asymmetric Hydrogenation of Ethyl Pyruvate: Relationship between Conversion and Enantioselectivity

The hydrogenation of ethyl pyruvate over cinchonidine-modified Pt exhibited intriguing transient behavior at the beginning of the reaction, and a period of rising rate and enantioselectivity was linked to conversion of substrate for a wide range of reaction temperatures and initial substrate concentrations. A “reaction-driven equilibration” of the surface environment for optimal enantioselective catalysis was proposed for these reactions carried out under conditions where moderate enantioselectivities are observed.