Demethylation of 5,n-di-tert-butyl-8,n-dimethoxy[2.n] metacyclophane-1-ynes with BBr3 to afford novel [n] benzofuranophanes

Akther, Thamina; Islam, Md Monarul; Matsumoto, Taisuke; Tanaka, Junji; Feng, Xing; Redshaw, Carl; Yamato, Takehiko

Abstract

© 2016 Elsevier B.V. All rights reserved. Novel [n]benzofuranophanes (n = 8 & 10) 2a-b have been prepared by successive intramolecular cyclization from 5,19-di-tert-butyl-8,22-dimethoxy[n]metacyclophane-1-yne (syn-1a-b) by treatment with BBr 3 in CH 2 Cl 2 at room temperature for 8h. [2.n]Benzofuranophanes 2a-b were also obtained by treatment of 1,2-di-endo-bromo-5,19-di-tert-butyl-8,22-dimethoxy[n] metacyclophane (meso-3a-b) with BBr 3 in CH 2 Cl 2 by using the same reaction conditions. 1 H NMR spectra of 2a-b reveals the formation of intramolecular hydrogen bonding between hydroxyl proton with the oxygen of the furan moiety and X-ray analysis shows that the lengths between H (OH) and O (furan) are 1.981 and 1.823 Å, respectively. The conformation of [8]benzofuranophane 2a in solution is rigid with restricted rotation around the diaryl linkage rather than [10] benzofuranophane 2b because of weak intramolecular hydrogen bonding and the short length of the cross-linking chain.

Citation

Akther, T., Islam, M. M., Matsumoto, T., Tanaka, J., Feng, X., Redshaw, C., & Yamato, T. (2016). Demethylation of 5,n-di-tert-butyl-8,n-dimethoxy[2.n] metacyclophane-1-ynes with BBr3 to afford novel [n] benzofuranophanes. Journal of molecular structure, 1122(15 October), 247-255. https://doi.org/10.1016/j.molstruc.2016.05.054

• Journal Article Type: Article
• Acceptance Date: May 17, 2016
• Online Publication Date: May 24, 2016
• Publication Date: Oct 15, 2016
• Deposit Date: Jun 22, 2016
• Publicly Available Date: Jun 22, 2016
• Journal: Journal of molecular structure
• Print ISSN: 0022-2860
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 1122
• Issue: 15 October
• Pages: 247-255
• DOI: https://doi.org/10.1016/j.molstruc.2016.05.054
• Keywords: [2.n]metacyclophanes, Demethylation, [n]Benzofuranophanes, Intramolecular hydrogen bond
• Public URL: https://hull-repository.worktribe.com/output/440062
• Publisher URL: http://www.sciencedirect.com/science/article/pii/S0022286016305002
• Additional Information: This article is maintained by: Elsevier; Article Title: Demethylation of 5,n-di-tert-butyl-8,n-dimethoxy[2.n]metacyclophane-1-ynes with BBr3 to afford novel [n]benzofuranophanes; Journal Title: Journal of Molecular Structure; CrossRef DOI link to publisher maintained version: http://dx.doi.org/10.1016/j.molstruc.2016.05.054; Content Type: article; Copyright: © 2016 Elsevier B.V. All rights reserved.
• Contract Date: Jun 22, 2016