Purinyl N3-Directed Palladium-Catalyzed C-H Alkoxylation of N9-Arylpurines: A Late-Stage Strategy to Synthesize N9-(ortho-Alkoxyl)arylpurines

A palladium-catalyzed alkoxylation of N-9-arylpurines with primary or secondary alcohols has been developed successfully, which is a rare C-H activation reaction of polynitrogenated purines and offers a late-stage strategy to synthesize N-9-(ortho-alkoxyl)-arylpurines. Although there are more than four nitrogen atoms present in the purine moiety, the reaction can be effectively conducted by sterically blocking the N-1 site for catalyst coordination and first employing the purinyl N-3 atom as a directing group.