Stereospecific Hydrogenolysis of Benzylic Alcohols over Pd/C.

Hydrogenolysis of tertiary benzylic alcohols on palladium on carbon (Pd/C) generally proceeds with inversion of configuration. However, little is known about the hydrogenolysis mechanism of primary and secondary benzylic alcohols. Literature precedents suggest that these substrates may interact differently with the catalyst. To study the mechanism, we synthesized a pair of deuterated diastereoisomers with a chiral center at the benzylic position. Chemical derivatization of the hydrogenolysis products showed that the reaction proceeds with inversion of configuration for these substrates.