First synthesis of 1,2,3-triazolo-linked (1,6)-alpha-D-oligomannoses (triazolomannoses) by iterative Cu(I)-catalyzed alkyne-azide cycloaddition

The iterative copper(I)-catalyzed cycloaddition ( rt or microwave) between an ethynyl alpha-C-mannoside and alkyl 6-azido-alpha-C-mannoside derivatives was suited to the ( 1,6)-ligation between alpha-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.