Cyclodextrin Rotaxane with Switchable Pirouetting

A [1]rotaxane with two threaded α-cyclodextrin (α-CD) wheels was synthesized in 92% yield using a one-pot process at room temperature that employed spontaneous α-CD threading onto a 12-carbon alkyl chain in water followed by an oxime condensation reaction that attached two boronic acid-containing stopper groups. Rapid pirouetting of the threaded α-CD wheels around the encapsulated dumbbell was switched “ON” or “OFF” by the presence of chemical additives that controlled boronate ester bond formation between the interlocked components.