Rotaxanes anion-assisted template synthesis

This seems to be the first rotaxane synthesis based on an anionic template and latest results indicate that this new strategy can be extended to ester- and acetal-based axles [70]. Hence the anionic procedure represents a powerful alternative to the rotaxane synthesis assisted by a neutral template. 

The interest in rotaxanes, pseudorotaxanes, and catenanes (i.e., molecules that contain non-covalently interlocked components) stems from their potential use as building blocks in molecular devices. Their syntheses usually rely on some sort of template assistance, such as the preorganization of the assembly s components around a metal center. While cationic templates have been widely used in this context, only a few examples of anion-directed synthesis of interlocked molecules have been reported. In fact, although rotaxanes and pseudorotaxanes have been prepared in this way (as discussed in this section), to date there is no reported example of anion-directed synthesis of catenanes. 

Reuter, C. Wienand, W. Hiibner, G.M. Seel, C. Vogtlc, F. High-yield synthesis of ester, carbonate, and acetal rotaxanes by anion template assistance and their hydrolytic dethreading. Chem. Eur. J. 1999, 5 (9), 2692 2697. 

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