Click Annulation of Pseudo[2]rotaxane to [2]Catenane Exploiting Homoditopic Nitrile <i>N</i>-Oxide

Abstract

A mild annulation reaction of a propargyl-terminated pseudorotaxane with a homoditopic stable nitrile N-oxide enabled the efficient synthesis of catenanes consisting of not only dibenzo-24-crown-8-ether (DB24C8) but also dibenzo-30-crown-10-ether (DB30C10) as a wheel component. A dynamic (1)H NMR study showed the highly enhanced mobility of the components of the DB30C10-based [2]catenane due to the enlarged wheel cavity.