Copper-Catalyzed Intramolecular Alkoxylation of Purine Nucleosides: One-Step Synthesis of 5'-O,8-Cyclopurine Nucleosides.

A novel copper-catalyzed intramolecular dehydrogenative alkoxylation of purine nucleosides has been developed successfully, providing the 5'-O,8-cyclopurine nucleosides in one-step with a yield up to 90%. The method, which utilized an inexpensive CuCl catalyst and a di-tert-butyl peroxide (DTBP) oxidant was suitable in a broad substrate scope and proceeded well even in gram scale.