[2]Catenane Synthesis via Covalent Templating

• Published in: Chemistry : a European journal 2021-02, Vol.27 (7), p.2310-2314
• Main Authors: Pilon, Simone, Ingemann Jørgensen, Steen, Maarseveen, Jan H.
• Format: Article
• Language: English
• Subjects: catenanes; Chemical synthesis; Chemistry; Communication; Communications; Covalence; covalent template; Linkages; mechanically interlocked molecules; planar chirality; Rotaxanes; template synthesis
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.202004925

After earlier unsuccessful attempts, this work reports the application of covalent templating for the synthesis of mechanically interlocked molecules (MiMs) bearing no supramolecular recognition sites. Two linear strands were covalently connected in a perpendicular fashion by a central ketal linkage. After subsequent attachment of the first strand to a template via temporary benzylic linkages, the second was linked to the template in a backfolding macrocyclization. The resulting pseudo[1]rotaxane structure was successfully converted to a [2]catenane via a second macrocyclization and cleavage of the ketal and temporary linkages. A covalent template strategy for the synthesis of mechanically interlocked molecules has been successfully employed to give a [2]catenane. This approach results in a [2]catenane devoid of supramolecular recognition sites. An inverted spiro intermediate is formed due to the action of a covalent template, which enforces an otherwise unfavorable macrocyclization. The trapped thread could be clipped into a second macrocycle giving a precatenane and, upon cleavage of the covalent templating linkages, the [2]catenane architecture.