Rhodium-Catalyzed Denitrogenative Transannulation of -Sulfonyl-1,2,3-triazoles with Glycals Giving Pyrroline-Fused -Glycosides.

Described here is a selective synthesis of 2,3-dihydropyrrole-fused -glycosides through rhodium-catalyzed denitrogenative transannulation of -sulfonyl-1,2,3-triazoles with glycals. A series of pyrroline-fused -glycosides are afforded in moderate to excellent yields with exclusive regioselectivity and stereoselectivity. Functional application of such a resultant product by oxidative addition and epoxidation is also explored. Notably, the treatment of a pyrroline-fused -glycoside () with TMSOTf efficiently leads to an interesting unexpected -nucleoside () via a TMSOTf-inducing ring opening/acetyl migration/ring closing reaction sequence.