Organocatalyzed Regioselective Synthesis of 1,5‐Disubstituted 1,2,3‐Triazolyl Glycoconjugates

A novel organocatalyzed [3+2] cycloaddition reaction of nitroolefins with glycosyl azides as well as organic azides has been developed for successful construction of 1,5‐disubstituted triazolyl glycoconjugates. This metal‐free and acid‐free, regioselective synthetic protocol proceeds in the presence of only Schreiner thiourea organocatalysts, which enable the required activation of nitroolefins through double hydrogen bonding. The straightforward, operationally simple, and regioselectivity of this methodology, complementing to the classical RuAAC catalyzed synthesis of 1,5‐disubstituted 1,2,3‐triazoles. In the presence of catalytic amount of Schreiner thiourea organocatalyst, organic azides react with a broad array of nitroolefins producing a series of diverse 1,5‐disubstituted 1,2,3‐ triazoles in good yields with excellent regioselectivity. A novel route using Schreiner thiourea mediated organocatalyzed [3+2] cycloaddition reaction of nitroolefins with diverse azides is devised to furnish high yield of 1,5‐disubstituted 1,2,3‐triazolyl glycoconjugates. The method has some notable features including metal‐free, straightforward, acid‐free, excellent regioselectivity operationally simple, wide substrate scope and high yielding. The Schreiner thiourea organocatalysts enable the required activation of nitroolefins through double hydrogen bonding.