Dynamic Kinetic Resolution of γ-Substituted Cyclic β-Ketoesters via Asymmetric Hydrogenation: Constructing Chiral Cyclic β-Hydroxyesters with Three Contiguous Stereocenters.

An efficient asymmetric hydrogenation of racemic γ-substituted cyclic β-ketoesters via dynamic kinetic resolution to provide chiral cyclic β-hydroxy esters with three contiguous stereocenters is reported. Using a chiral spiro iridium catalyst (R)-5 (Ir-SpiroSAP), a series of racemic γ-aryl/alkyl substituted cyclic β-ketoesters were hydrogenated to the corresponding chiral cyclic β-hydroxy esters in high yields (84-97%) with good to excellent enantioselectivities (69->99% ee) and cis,cis-selectivities (up to >99:1).