Complexation equilibrium in a substrate - MgCl2(CaCl2) - Pd/c catalytic system and the influence of its position on asymmetric induction in hydrogenation of N-acetyl-dehydrophenylalanyl-S-proline

Article abstract of DOI:10.1007/BF01457764

The role of Ca and Mg salts as promoters of asymmetric induction in hydrogenation of N-acetyl-dehydrophenylalanyl-S-proline in a substrate - MX₂ - Pd/C catalytic system was studied. The data of potentiometric titration, ¹H NMR spectroscopy, and the value of diastereomeric excess (de) of the resulting N-acetyl-R-phenylalanyl-S-proline indicate the complexation of the substrate with calcium and magnesium chlorides in an alcoholic solution. Ionization and equilibrium constants of the complex were determined. Excess salt shifts the equilibrium toward the complex formation, which increases de up to 70 %.