For the purine scope, substituents were tolerated in a variety of positions, resulting in conversion to the desired products in > 80% for nucleosides 10-15. Only bulky substituents in the purine 8position (i.e., 16) resulted in the conversion dropping to 61% as well as forming a glycosidic bond at the N3 position rather than N9 as observed with nucleosides 10-15 (Figure ).