A Practical Approach for Ambient‐Pressure Hydrogenations Using Pd on Porous Glass

A Pd on porous glass catalyst system was used in the liquid-phase hydrogenation of terpenoid substrates with dihydrogen at room temperature and atmospheric pressure. A multitude of substances were hydrogenated selectively with yields of 90-100 %. In all experiments, only C--C, C--N, and N--N double bonds were hydrogenated. Studies revealed that carbonyl and aromatic double bonds are inert towards catalytic reduction with dihydrogen under the conditions employed. In some cases, hydrogenation was accompanied by isomerization, so that treatment of beta-pinene, for example, afforded isomeric alpha-pinene, which was subsequently hydrogenated to pinane.