Mechanical Force Induces Ylide-Free Cycloaddition of Nonscissible Aziridines

The application of aziridines as nonvulnerable mechanophores is reported. Upon exposure to a mechanical force, stereochemically pure nonactivated aziridines incorporated into the backbone of a macromolecule do not undergo cis-trans isomerization, thus suggesting retention of the ring structure under force. Nonetheless, aziridines react with a dipolarophile and seem not to obey conventional reaction pathways that involve C-C or C-N bond cleavage prior to the cycloaddition. Our work demonstrates that a nonvulnerable chemical structure can be a mechanophore.