Efficient Synthesis of Differentiated syn-1,2-Diol Derivatives by Asymmetric Transfer Hydrogenation-Dynamic Kinetic Resolution of α-Alkoxy-Substituted β-Ketoesters.

Asymmetric transfer hydrogenation was applied to a wide range of racemic aryl α-alkoxy-β-ketoesters in the presence of well-defined, commercially available, chiral catalyst Ru(II) -(N-p-toluenesulfonyl-1,2-diphenylethylenediamine) and a 5:2 mixture of formic acid and triethylamine as the hydrogen source. Under these conditions, dynamic kinetic resolution was efficiently promoted to provide the corresponding syn α-alkoxy-β-hydroxyesters derived from substituted aromatic and heteroaromatic aldehydes with a high level of diastereoselectivity (diastereomeric ratio (d.r.

General asymmetric hydrogenation of 2-alkyl- and 2-aryl-substituted quinoxaline derivatives catalyzed by iridium-difluorphos: unusual halide effect and synthetic application.

A general asymmetric hydrogenation of a wide range of 2-alkyl- and 2-aryl-substituted quinoxaline derivatives catalyzed by an iridium-difluorphos complex has been developed. Under mild reaction conditions, the corresponding biologically relevant 2-substituted-1,2,3,4-tetrahydroquinoxaline units were obtained in high yields and good to excellent enantioselectivities up to 95%. With a catalyst ratio of S/C = 1000 and on a gram scale, the catalytic activity of the Ir-difluorphos complex was maintained showing its potential value.

Highly diastereo- and enantioselective synthesis of monodifferentiated syn-1,2-diol derivatives through asymmetric transfer hydrogenation via dynamic kinetic resolution.

The first enantio- and diastereoselective approach to alpha-alkoxy-substituted syn-beta-hydroxyesters through highly efficient catalytic asymmetric transfer hydrogenation via dynamic kinetic resolution reactions from the corresponding racemic beta-ketoesters is described. In this atom-economical process, two contiguous stereogenic centers are generated simultaneously with an excellent diastereoselectivity (up to 99/1) and enantioselectivity (up to 99%), allowing a rapid access to a wide variety of aromatic and heteroaromatic monodifferentiated syn-1,2-diols.