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Tranfić Bakić M, Iuliano V, Talotta C, Geremia S, Hickey N, Spinella A, De Rosa M, Soriente A, Gaeta C, Neri P. Threading of Conformationally Stable Calix[6]arene Wheels Substituted at the Methylene Bridges. J Org Chem 2019; 84:11922-11927. [PMID: 31418261 DOI: 10.1021/acs.joc.9b01779] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Calix[6]arenes disubstituted at the methylene bridges, which are stable in the cone or 1,2,3-alternate conformation, form pseudorotaxanes with dialkylammonium axles. The cone wheel-based pseudorotaxanes are 10-100 times more stable than those obtained with the native conformationally mobile calix[6]arene wheel, as a consequence of their higher degree of preorganization. The threading of conformationally stable 1,2,3-alternate calix[6]arenes is unprecedented in the literature. Therefore, very peculiar NMR features are here evidenced for this threading process involving the less symmetrical 1,2,3-alternate calix[6]arene conformation, which implies a peculiar rototranslation motion of the axle.
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Affiliation(s)
- Marina Tranfić Bakić
- Department of Chemistry and Biochemistry, Faculty of Food Technology and Biotechnology , University of Zagreb , Pierottijeva 6 , 10000 Zagreb , Croatia
| | - Veronica Iuliano
- Laboratory of Supramolecular Chemistry, Department of Chemistry and Biology "A. Zambelli" , University of Salerno , Via Giovanni Paolo II 132 , I-84084 Fisciano , Salerno , Italy
| | - Carmen Talotta
- Laboratory of Supramolecular Chemistry, Department of Chemistry and Biology "A. Zambelli" , University of Salerno , Via Giovanni Paolo II 132 , I-84084 Fisciano , Salerno , Italy
| | - Silvano Geremia
- Centro di Eccellenza in Biocristallografia Dipartimento di Scienze Chimiche e Farmaceutiche , Università di Trieste , via L. Giorgieri 1 , I-34127 Trieste , Italy
| | - Neal Hickey
- Centro di Eccellenza in Biocristallografia Dipartimento di Scienze Chimiche e Farmaceutiche , Università di Trieste , via L. Giorgieri 1 , I-34127 Trieste , Italy
| | - Aldo Spinella
- Laboratory of Supramolecular Chemistry, Department of Chemistry and Biology "A. Zambelli" , University of Salerno , Via Giovanni Paolo II 132 , I-84084 Fisciano , Salerno , Italy
| | - Margherita De Rosa
- Laboratory of Supramolecular Chemistry, Department of Chemistry and Biology "A. Zambelli" , University of Salerno , Via Giovanni Paolo II 132 , I-84084 Fisciano , Salerno , Italy
| | - Annunziata Soriente
- Laboratory of Supramolecular Chemistry, Department of Chemistry and Biology "A. Zambelli" , University of Salerno , Via Giovanni Paolo II 132 , I-84084 Fisciano , Salerno , Italy
| | - Carmine Gaeta
- Laboratory of Supramolecular Chemistry, Department of Chemistry and Biology "A. Zambelli" , University of Salerno , Via Giovanni Paolo II 132 , I-84084 Fisciano , Salerno , Italy
| | - Placido Neri
- Laboratory of Supramolecular Chemistry, Department of Chemistry and Biology "A. Zambelli" , University of Salerno , Via Giovanni Paolo II 132 , I-84084 Fisciano , Salerno , Italy
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Abstract
Macrocyclic compounds (calix[4]- and calix[6]arene derivatives) with aryl rings interconnected by spirocyclopropyl groups have been synthesized and structurally characterized. The compounds were prepared by the reaction of dichlorocarbene with calixarenes possessing exocyclic double bonds at the bridges, followed by reductive perdechlorination of the spirocyclopropyl groups. In all systems, pairs of geminal rings connected to the quaternary spiro carbon atoms are oriented anti, and the methylene groups of the cyclopropyl rings are located in isoclinal positions. Calix[6]rotane adopts in the crystal and in solution a 1,3,5-alternate conformation. The presence of the spirocyclopropyl groups increases the rigidity of the macrocyclic ring.
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Affiliation(s)
- Ori Shalev
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel
| | - Silvio E Biali
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel
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