Regio- and Enantioselective Asymmetric Transfer Hydrogenation of One Carbonyl Group in a Diketone through Steric Hindrance.

On the basis of steric hindrance, one carbonyl group in a diketone can be reduced in a regioselective manner, with high enantioselectivity. The methodology can be extended to ketones with varied length of hydrocarbon chain spacing, and the products can be converted by oxidation to hydroxy esters or lactones without loss of enantiopurity.