Liu C, Xie J.-H, * Li Y.-L, Chen J.-Q, Zhou Q.-L. * Nankai University, Tianjin, P. R. of
China
Asymmetric Hydrogenation of α,α′-Disubstituted Cycloketones through Dynamic Kinetic
Resolution: An Efficient Construction of Chiral Diols with Three Contiguous Stereocenters.
Angew. Chem. Int. Ed. 2013;
52: 593-596
Key words
ruthenium - asymmetric hydrogenation - dynamic kinetic resolution - cycloketones
Significance
A ruthenium-catalyzed hydrogenation of racemic, diastereomeric α′-aryl cycloketones
is reported. The reaction is a dynamic kinetic resolution (DKR) and gives chiral diols
with three contiguous stereocenters with high yield and enantioselectivity.
Comment
As the substrate consists of a mixture of four stereoisomers, exerting enantiocontrol
in hydrogenation is a challenging feat. The DKR sets the α,α′-stereocenters and hydrogenates
the ketone. When R1 is an ester, lactonization occurs and the lactone is hydrogenated to the diol. The
α′-aryl substitutent is essential in the DKR. The synthetic utility of the DKR is
demonstrated in the synthesis of (+)-γ-lycorane.
