Challenges and Opportunities in the Post‐Synthetic Modification of Interlocked Molecules

• Published in: Angewandte Chemie International Edition 2021-07, Vol.60 (31), p.16778-16799
• Main Authors: Waelès, Philip, Gauthier, Maxime, Coutrot, Frédéric
• Format: Article
• Language: English
• Subjects: Chemical Sciences; interlocked molecules; mechanical bonds; Organic chemistry; post-synthetic modification; rotaxanes; self-assembly; Shafts (machine elements)
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202007496

Several strategies have been successfully utilised to obtain a wide range of interlocked molecules. However, some interlocked compounds are still not obtained directly and/or efficiently from non‐interlocked components because the requisites for self‐assembly cannot always be enforced. To circumvent such a synthetic problem, a strategy that consists of synthesizing an isolable and storable interlocked building block in a step that precedes its modification is an appealing chemical route to more sophisticated interlocked molecules. Synthetic opportunities and challenges are closely linked to the fact that the mechanical bond might greatly affect the reactivity of a functionality of the encircled axle, but that the interlocked architecture needs to be preserved during the synthesis. Hence, the mechanical bond plays a fundamental role in the strategy employed. This Review focuses on the challenging post‐synthetic modifications of interlocked molecules, sometimes through cleavage of the axle's main chain, but always with conservation of the mechanical bond. This Review highlights the challenges in covalently modifying interlocked molecules, whereby the chemical bond plays a fundamental role in the strategy employed. Such routes can involve cleavage of the axle's main chain, but always with conservation of the mechanical bond, and allow access to more sophisticated interlocked molecules.