A Chemoselective Hydrogenation of α,β-Unsaturated Carbonyl Compounds

Abstract

A silica-supported PdCl2 catalyst was prepared from silica gel (2 g) and PdCl2 (0.010-0.015 g) by mixing in a mortar. The α,β-unsaturated ketone 1 (0.0025 mol) and 2 mL of MeOH:HCOOH:H2O (1:2:3) were charged to an Erlenmayer flask in the presence of silica-supported PdCl2 catalyst. The mixture was then irradiated in the microwave oven to afford ketone 2 in 84% yield without over-reduction, though the identical reaction under reflux or ultrasounds conditions gave the ketone in moderate yields with the formation of the over-reductive alcohol. 15 Substrates were examined in this paper (8-96% yields).