A new class of cationic cyclodextrins: synthesis and chemico-physical properties

A new class of positively charged triazole-bridged beta-cyclodextrin (beta-CD) derivatives have been synthesized in excellent yields (over 70%) through a copper-catalyzed azide-alkyne cycloaddition (CuAAC), starting from 6(I)-azido-6(I)-deoxy-beta-CD or its permethylated derivative and a series of 1-butyl-3-alkynylimidazolium salts. The regioselective azide/alkyne [3 + 2] cycloaddition was efficiently carried out using metallic copper as the catalyst, affording very clean products. Easy access to such hybrid molecules that combine the properties of CDs and ionic liquids, may pave the way to a number of new applications in analytical chemistry and catalysis.