Asymmetric hydrogenation of unsaturated carbonyl compounds catalyzed by BINAP-Ru(II) complexes. Enantioselective synthesis of γ-butyrolactones and cyclopentanones

Asymmetric hydrogenation of 2- and 4-alkylidene-γ-butyrolactones and 2-alkylidenecyclopentanones catalyzed by BINAP—Ru(II) complexes affords the corresponding γ-butyrolactones and cyclopentanones in 94–98% ee. Hydrogenation of (E)- and (Z)-2-propylidene-γ-butyrolactone catalyzed by the same catalyst gave the products with the same absolute configuration and in almost equal enantioselectivities, which shows that olefin geometry does not affect the stereochemistry and enantioselectivity.