Conditioning of Palladium-on-carbon (Pd/C) for Uniform Cinchonidine Modification to Perform Highly Enantioselective Hydrogenation

Cinchonidine (CD)-modified palladium catalyst gave the high product ee when a commercial wet Pd/C was used after the co-evaporation pretreatment. The improvement in the ee was attributed to removal of water from a specific Pd/C interior. The use of a water-soluble CD·HCl salt resulted in the high ee without pretreatment.