Cooperative perfunctionalization and partial labeling of 6-azido-6-deoxy-α-cyclodextrin through copper(I)-catalyzed azide-alkyne cycloaddition

In a microwave and ligand-assisted cyclodextrin click cluster synthesis, we observed the cooperative perfunctionalization in the click reaction of 6-azido-6-deoxy-α-cyclodextrin under our optimized reaction conditions. MALDI-MS data and partial fluorescein labeling via the one-pot/stepwise methods confirmed the occurrence of cooperative perfunctionalization: the fully triazole-functionalized cyclodextrin click cluster became the major product with limited alkyne equivalents. To the best of our knowledge, this work constitutes the first example of a 'cooperative' click reaction of an azido-cyclodextrin. This cooperative perfunctionalization of cyclodextrin click clusters offers useful synthetic insights into the partial reporter labeling strategy using azido-cyclodextrin.