Formation of Pd/C-ethylenediamine complexes [Pd/C (en)] and it's application to selective hydrogenations

Abstract

The chemoselective hydrogenation of an organic compound containing two or more reducible functional groups is a useful method in organic synthesis. We have found that a Pd/C catalyst formed an isolable complex with the ethylenediamine (en) employed as catalytic poison, and its complex catalyst [Pd/C(en)] chemoselectively hydrogenated a variety of reducible functionalities distinguishing O-benzyl, N-Cbz and O-TBDMS protective groups, benzyl alcohols and epoxides. The catalyst also regioselectively hydrogenolyzed 1,2-epoxides to sec-alcohols depending upon the employed reaction conditions.