Effect of Methyl-substitution of the Quinoline Ring of Cinchona Alkaloids on the Performance as a Modifier for the Enantioselective Hydrogenation of ( E )-2,3-di(4-methoxyphenyl)propenoic Acid Over Pd/C: Kinetic Analysis

The asymmetric hydrogenation of (E)-2,3-di(4-methoxyphenyl)propenoic acid was conducted over Pd/C chirally modified with cinchona alkaloids methyl-substituted at 2′-position of the quinoline ring. It is revealed that the adsorption strength of the modifiers and the intrinsic enantioselectivity at the modified sites are decreased by the methyl-substitution. The intrinsic enantioselectivity of the modifier is correlated to kinetic parameters.