ChemInform Abstract: Chiral Ruthenium‐Catalyzed Hydrogenation of β‐Keto Sulfoxides.

Abstract

-044Chiral Ruthenium-Catalyzed Hydrogenation of β-Keto Sulfoxides.-The diastereoselectivity of ruthenium-catalyzed reduction of β-keto sulfoxides is studied. Hydrogenation of optically active keto sulfoxide (I) in the presence of achiral ruthenium catalysts proceeds with moderate stereoselectivity, while β-hydroxy sulfoxide (II) is obtained with excellent diastereomeric excess in the presence of a planar chiral biphenyl ligand (MeO-biphep). It is shown that the diastereoselectivity of reduction is governed mainly by the catalyst chirality, while the chirality of sulfoxide plays a minor role. Thus, reduction of racemic β-keto sulfoxides (IV) in the presence of a chiral ruthenium catalyst followed by desulfurization provides alcohols (VI) in moderate to high optical purity.