Self‐assembling [2]‐ and [3]Rotaxanes from Secondary Dialkylammonium Salts and Crown Ethers

The self‐assembly of three new rotaxanes—two [2]rotaxanes and a [3]rotaxane—formed by a “threading followed by stoppering” approach is described. These template‐directed syntheses rely on the formation of pseudorotaxane intermediates, which self‐assemble in solution from functionalized secondary dialkylammonium hexafluorophosphate threads and macrocyclic polyether rings (either dibenzo‐[24]crown‐8 or its asymmetric constitutional isomer). The stoppers—substituted 1,2,3‐triazoles–were created by thermally allowed 1,3‐dipolar cycloadditions between azido groups, which terminate the threads, and di‐ tert ‐butyl acetylenedicarboxylate.