Organocatalytic [3+2] Cycloadditions: Toward Facile Synthesis of Sulfonyl-1,2,3-Triazolyl and Fully Substituted 1,2,3-Triazolyl Glycoconjugates

Abstract

A general strategy was developed for the synthesis of Sulfonyl-1,2,3-triazolyl glycoconjugates (5a-n) and fully decorated 1,2,3triazolyl glycoconjugates (6a-w & 6 aa-6 ah) in the presence of catalytic amounts of organocatalyst. Ramachary-Bressy-Wang organocatalytic azide-ketone [3 + 2]-cycloaddition (OrgAKC) reaction of b-keto sulfones act as internal alkynes with glycosyl azides are reported for the synthesis of Sulfonyl-1,2,3-triazolyl glycoconjugates at 50 8C in good to excellent yields of products in the presence of catalytic amounts of pyrrolidine (10 mol %). In the similar way, Ramachary OrgAKC reaction of a variety of substituted phenyl ketones as internal alkynes with different glycosyl azides are reported for the synthesis of 1,2,3-triazolyl glycoconjugates at room temperature in good to excellent yields with high regioselectivity in the presence of catalytic amounts of DBU (10 mol %) using DMSO as solvent. The work mainly focuses on the application of this methodology to making glycoconjugates and establishes an alternative tool for the synthesis of fully decorated glyco-triazoles from the already known copper catalysed azide-alkyne [3 + 2] cycloaddition (CuAAC), RuAAC and IrAAC click reactions.

CoFe2O4/Cu(OH)2 magnetic nanocomposite: an efficient and reusable heterogeneous catalyst for one-pot synthesis of β-hydroxy-1,4-disubstituted-1,2,3-triazoles from epoxides

“…38 Ramachary-Bressy-Wang cycloaddition of enolate intermediates and organic azides is the other basic method for one-pot preparation of 1,4-disubstituted-1,2,3-triazoles. [39][40][41][42][43] The reduction of work-up procedures and purication steps, high purity of desired products, short reaction times, high to excellent yields are among the signicant benets of multicomponent one-pot reactions. 44,45 Furthermore, the reaction involving ring opening of epoxides with organic azides in water solvent occurs with perfect regioselectivity and takes advantage of green and benign conditions.…”

Versatile Synthetic Platform for 1,2,3-Triazole Chemistry

“…Mandal and co-workers developed a regioselective, efficient, straightforward, as well as environmentally friendly protocol for the synthesis of sulfonyl-1,2,3-triazolyl glycoconjugates 311 and completely substituted 1,2,3-triazolyl glycoconjugates 312 from glycosyl azides 307 , β-keto sulfone 308 , and substituted phenyl aldehyde 309 using DMSO in an open flask at 50 °C for 1 h and DBU and DMSO for 1 h at RT, respectively (Scheme ). For the DBU-promoted reaction, they found that aprotic polar solvents such as DMSO and DMF gave a good result compared to that with MeOH and CH 3 CN (30% yield).…”

An Overview on the ChemicalN‐Functionalization of Sugars and Formation ofN‐Glycosides

“…European Journal of Organic Chemistry cycloaddition between -keto sulfones/substituted phenyl ketone and glycosyl azides for the formation of a diverse substituted 1,2,3-triazolyl glycoconjugates (Scheme 25). [42] Scheme 25. Formation of sulfonyl-1,2,3-triazolyl and 1,2,3-triazolyl glycoconjugates.…”

“…Recently our group have evaluated the straight forward strategy involving organocatalytic enamine‐azide/enolate‐azide cycloaddition between β ‐keto sulfones/substituted phenyl ketone and glycosyl azides for the formation of a diverse substituted 1,2,3‐triazolyl glycoconjugates (Scheme ) …”