Hydrogenation of
α,
β-unsaturated acid over cinchonidine-modified Pd/C results in poor enantioselectivity in water, but the selectivity becomes
much higher when Pd/C is admixed with a small amount of a hydrophobic water-insoluble organic solvent. With the admixed catalyst,
the product is easily removed by separation of the aqueous phase under the hydrogen atmosphere and the remaining catalyst
can be reused.
Keywords Enantioselective - Hydrogenation - Pd/C - Aqueous - Unsaturated acid