Chemo- and Regioselective Ring-opening of Donor-Acceptor Oxiranes with N-Heteroaromatics

The first ring-opening of D–A oxiranes with N-heteroaromatics in a chemoselective C–C bond cleavage manner was achieved. In the presence of 5 mol% of Y(OTf)3 as the catalyst, diverse N-heteroaromatics, including benzotriazoles, purines, substituted benzimidazole, imidazole and pyrazole, reacted well with various D–A oxiranes, providing acyclic nucleoside analogues containing a N-glycosidic bond in up to 97% yield and up to >95 : 5 regioselectivity. Through simple transformation, the Ganciclovir analogue could also be obtained.