Asymmetric Hydrogenation of α-Alkyl-Substituted ß-Keto Esters and Amides through Dynamic Kinetic Resolution.

ABSTRACT

Asymmetric hydrogenation of α-alkyl-substituted ß-keto esters and amides with the DIPSkewphos/3-AMIQ-Ru(II) catalyst system through dynamic kinetic resolution was examined. A series of ß-keto esters and amides with a simple or functionalized α-alkyl group were applicable to this reaction, affording the α-substituted ß-hydroxy esters and amides in ≥99% ee (anti/syn ≥ 991) in many cases. The 5 g scale reaction was readily achieved. The mode of enantio- and diastereoselection in the transition state model was proposed.