Rh-Catalyzed Hydrogenation of Olefins with Zn Metal and Water

Significance

A very simple and highly practical method for the reduction of double bonds, including α,β-unsaturated ketones, is described. Zinc and water are used as reducing agents. The process does not require special precautions needed for the handling of flammable hydrogen gas or complex hydrides or the use of a pressure apparatus. In the case of α,β-enones, including cyclic systems, the reaction is completely selective for the C=C reduction, so that it complements well the Luche method for the reduction of enones to allylic alcohols. This method can be conveniently used for the preparation of deuterium-labeled compounds, using cheap D₂O as the deuterium source.