Asymmetric 1,2-Reduction of Enones with Potassium Borohydride Catalyzed by Chiral N,N′-Dioxide-Scandium(III) Complexes

The first catalytic enantioselective 1,2-reduction of enones with 0.45 mol equiv potassium borohydride solution catalyzed by a chiral N,N'-dioxide-Sc(III) complex catalyst was accomplished under mild reaction conditions. A number of optically active allylic alcohols were obtained in good to excellent enantioselectivities (up to 95% ee) with nearly quantitative yields.