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

Abstract

Abstract A general strategy was developed for the synthesis of Sulfonyl‐1,2,3‐triazolyl glycoconjugates ( 5a–n ) and fully decorated 1,2,3‐triazolyl 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 β‐keto sulfones act as internal alkynes with glycosyl azides are reported for the synthesis of Sulfonyl‐1,2,3‐triazolyl glycoconjugates at 50 °C 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.