Substrate adsorption on the cinchonidine-modified Pd/C during the enantio-differentiating hydrogenation as a vital stereocontrol factor

Cinchonidine-modified Pd/C effective for the enantioselective hydrogenation of phenylcinnamic acid was not effective for 4-Py and 3-Py under the standard conditions, but the ee with 4-Py improved at the low substrate/cinchonidine ratio.