Syntheses and NMR Spectroscopic Studies of Bridged and Capped Calix[6]arenes: High-Yield Syntheses of Unimolecular Caged Compounds from Calix[6]arene

Hideyuki Otsuka, Koji Araki, Hitoshi Matsumoto, Takaaki Harada, Seiji Shinkai

Research output: Contribution to journalArticle

57 Citations (Scopus)

Abstract

Calix[6]arenes were bridged with a xylenyl unit or capped with a mesitylenyl unit, and their conformational properties were examined by spectroscopic methods. As previously reported by Gutsche et al., the calix[6]arene bridged on 1, 4-phenyl units could enjoy slow ring inversion. The calix[6]arene bridged on 1, 2-phenyl units also showed the ring inversion behavior, whereas in the calix[6]arene bridged on 1, 3-phenyl units, ring inversion was virtually suppressed because of destabilization of the transition state. The capping of 1, 3,5-tri-O-alkylated calix[6]arenes with 1, 3,5-tris(bromomethyl)benzene gave the products in high yields (80–91%). This advantage was accounted for by the C3 symmetrical complementarity of these two reactants. In these capped products, ring inversion was inhibited under the present measurement conditions, and the presence of a unimolecularly closed inner cavity was suggested on the basis of 1H NMR spectroscopy and MM3 calculations.

Original languageEnglish
Pages (from-to)4862-4867
Number of pages6
JournalJournal of Organic Chemistry
Volume60
Issue number15
DOIs
Publication statusPublished - Jul 1 1995

All Science Journal Classification (ASJC) codes

  • Organic Chemistry

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