Enantioface-differentiating (Asymmetric) Hydrogenation of Keto Ester with Modified Nickel Catalyst. XXXII. Structural Requirements of Modifying Reagent and Substrate

The enantioface-differentiating hydrogenation of α-, β-, γ-, and δ-keto esters over α-, β-, and γ-amino acid–MRNi has been conducted. The optimum enantio-differentiating power of α-amino acid-MRNi has been found in the hydrogenation of the β-keto ester and that of β-amino acid-MRNi found in the hydrogenation of the γ-keto ester. The results have been explained in terms of the intermolecular recognition between substrate and modifying reagent through the functional groups.