Palladium/Zinc Co-Catalyzed Asymmetric Hydrogenation of γ-Keto Carboxylic Acids.

A palladium-catalyzed asymmetric hydrogenation of levulinic acid has been successful developed by using Zn(OTf) 2 as co-catalyst. The present method not only has provided a strategy in the palladium-catalyzed asymmetric hydrogenation of ketone, but also allowed the preparation of a wide range of chiral I³-valerolactones in good yields with excellent enantioselectivities.