Process for the synthesis of 2′-O-substituted purine nulceosides

摘要

The present invention provides an improved process for the synthesis of 2′-O-substituted purine nucleosides. The process includes anhydro or thioanhydro ring opening of a selected 8,2′-cyclopurine nucleoside with a weak nucleophile in the presence of a Lewis acid ester, followed by reduction to afford the desired 2′-O-substituted purine nucleoside.