Asymmetric Transfer Hydrogenation of rac-α-(Purin-9-yl)cyclopentones via Dynamic Kinetic Resolution for the Construction of Carbocyclic Nucleosides.

An asymmetric transfer hydrogenation via dynamic kinetic resolution of a broad range of rac- α-(purin-9-yl)cyclopentones was first developed. A series of cis-β-(purin-9-yl)cyclopentanols were obtained with up to 97% yield, >20/1 dr, and >99% ee. This also provides an efficient synthetic route to a variety of chiral carbocyclic nucleosides.