General Asymmetric Hydrogenation of α-Branched Aromatic Ketones Catalyzed by TolBINAP/DMAPEN−Ruthenium(II) Complex

A catalyst system consisting of RuCl2[(S)-tolbinap][(R)-dmapen] and t-C4H9OK in 2-propanol effects asymmetric hydrogenation of arylglyoxal dialkylacetals to give the α-hydroxy acetals in up to 98% ee. Hydrogenation of racemic α-amidopropiophenones under dynamic kinetic resolution predominantly gives the syn alcohols in up to 99% ee and >98% de, while the reaction of racemic bezoin methyl ether gives the anti alcohols in excellent stereoselectivity.