Vinyl sulfone modified-azidofuranoside building-blocks: 1,4-/1,5-disubstituted-1,2,3-triazole linked trisaccharides via an aqueous/ionic-liquid route and “Click” chemistry

1,5-Disubstituted 1,2,3-triazole (1,5-DT) linked disaccharides have been synthesized from stable building blocks having both vinyl sulfone and azido groups using aqueous ionic-liquid media. These building blocks containing secondary azido groups do not undergo self-coupling but react with the externally delivered primary azidosugars. The disaccharides are coupled with appropriate building blocks for the preparation of the first ever 1,5-DT linked- and 1,4-/1,5-DT-linked trisaccharides using aqueous ionic-liquid and water–butanol based “click” chemistry, respectively.