Asymmetric Hydrogenation of Tetrasubstituted Cyclic Enones to Chiral Cycloalkanols with Three Contiguous Stereocenters.

A highly efficient iridium-catalyzed asymmetric hydrogenation of tetrasubstituted cyclic enones has been developed for the enantioselective synthesis of chiral cycloalkanols with three contiguous stereocenters. The C═O and C═C bonds of the enone substrates were hydrogenated sequentially in one pot with excellent enantioselectivity (92 to >99% ee) and diastereoselectivity (dr 95:5 to >99:1). The reaction provided a practical approach to all of the stereoisomers of the antiulcer drug rosaprostol.