Highly Chemoselective Catalytic Hydrogenation of Unsaturated Ketones and Aldehydes to Unsaturated Alcohols Using Phosphine-Stabilized Copper(I) Hydride Complexes

A base metal hydrogenation catalyst composed of the phenyldimethylphosphine-stabilized copper(I) hydride complex provides for the highly chemoselective hydrogenation of unsaturated ketones and aldehydes to unsaturated alcohols, including the regioselective 1,2-reduction of α,β-unsaturated ketones and aldehydes to allylic alcohols. The active catalyst can be derived in situ by phosphine exchange using commercial [(Ph3P)CuH]6 or from the reaction of copper(I) chloride, sodium tert-butoxide, and dimethylphenylphosphine under hydrogen. The catalyst derived from 1,1,1-tris(diphenylphosphinomethyl)ethane is mechanistically interesting but less synthetically useful.