O‐Acylative Vinylation of Cyclodextrin‐Based [3]Rotaxane Towards Rotaxane Crosslinkers

The acylation of a cyclodextrin‐based [3]rotaxane was implemented with anhydride reagents following a facile procedure. Methacrylic anhydride facilitated the introduction of a vinyl‐group into the rotaxane structure toward achieving a crosslinker. Interestingly, only a few methacrylic units were attached to the cyclodextrin at reaction temperatures of up to 60 °C even with an excess amount of the reagent, probably due to steric hindrance. Therefore, the number of vinyl groups on the [3]rotaxane framework was easily controlled to be approximately two units via a simple random acylation, which worked effectively as a facile synthesis route for the rotaxane crosslinker. The acylation behavior was investigated in detail by NMR and MALDI‐TOF‐MS analyses. Such a proposed approach will help overcome the trade‐off between convenience and utility associated with the mono‐modification of cyclodextrins.