Asymmetric Hydrogenation of α-Purine Nucleobase-Substituted Acrylates with Rhodium Diphosphine Complexes: Access to Tenofovir Analogues.

The first asymmetric hydrogenation of α-purine nucleobase-substituted α,β-unsaturated esters, catalyzed by a chiral rhodium (R)-Synphos catalyst, has been developed. A wide range of mono- and disubstituted acrylates were successfully hydrogenated under very mild conditions in high yields with good to excellent enantioselectivities (up to 99% ee). This method provides a convenient approach to the synthesis of a new kind of optically pure acyclic nucleoside and Tenofovir analogues.