First synthesis of 1,2,3-triazolo-linked (1,6)-α-d-oligomannoses (triazolomannoses) by iterative Cu(i)-catalyzed alkyne–azide cycloaddition

The iterative copper(I)-catalyzed cycloaddition (rt or microwave) between an ethynyl α-C-mannoside and alkyl 6-azido-α-C-mannoside derivatives was suited to the (1,6)-ligation between α-D-mannose units through 1,4-disubstituted triazole bridges, thus resulting in the formation of linear oligomers (80–90% yield) with alternating triazole and mannose fragments up to a triazolo-pentamannose derivative.