Visible-Light-Mediated β-C(sp3)-H Amination of Glycosylimidates: En Route to Oxazoline-Fused/Spiro Nonclassical Bicyclic Sugars.

A straightforward route has been developed for the diastereoselective synthesis of nonclassical conformationally constrained oxazoline-fused and spiro bicyclic sugars bearing a quaternary center via selective β-C-H amination of appropriately positioned glycosylimidates. The desired transformation proceeds via the generation of imidate N-radicals under visible-light conditions followed regioselective intramolecular N-C bond formation. The reactions tolerate broad functional groups under the optimized conditions. Furthermore, the synthetic utility of oxazoline-fused bicyclic sugar moiety is demonstrated through the glycosylation reactions.