Using Diels-Alder reactions to synthesize [2]rotaxanes under solvent-free conditions

Diels-Alder reactions of the terminal alkyne units of SiO2-supported [2]pseudorotaxanes with 1,2,4,5-tetrazine derivatives proceed efficiently through solid-to-solid contact to provide both asymmetric and symmetric [2]rotaxanes incorporating either 24- or 25-membered-ring macrocycles.