1 Demethylation of 5,n-di-tert-butyl-8,n-dimethoxy[2.n] metacyclophane-1-ynes with BBr 3 to afford novel [n]benzofuranophanes Thamina Akther a , Md. Monarul Islam a,b , Taisuke Matsumoto c , Junji Tanaka c , Xing Feng d , Carl Redshaw e and Takehiko Yamato a, * a Department of Applied Chemistry, Faculty of Science and Engineering, Saga University, Honjo- machi 1, Saga-shi, Saga 840-8502, Japan. Fax: (internat.) + 81(0)952/28-8548. b Chemical Research Division, Bangladesh Council of Scientific and Industrial Research(BCSIR), Dhanmondi, Dhaka-1205, Bangladesh c Institute of Material Chemistry and Engineering, Kyushu University, 6-1, Kasugakoen, Kasuga 816-8580, Japan d Beijing Institute of Graphic Communication, Beijing 102600, PR China e Department of Chemistry, The University of Hull, Cottingham Road, Hull, Yorkshire, HU6 7RX, UK _________________________________________________________________ Abstract: 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 8 h. [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 same reaction condition. 1 H NMR spectra of 2a–b reveals the formation of intramolecular hydrogen bonding between hydroxyl proton with the oxygen of furan moiety and X-ray analysis shows that the length between H (OH) and O (furan) are 1.981 and  , respectively. The conformation of [8]benzofuranophane 2a in solution is rigid and restricted rotation around the diaryl linkage rather than [10]benzofuranophane 2b because of weak intramolecular hydrogen bonding and short length of cross-linking chain. Keywords: [2.n]metacyclophanes, demethylation, [n]benzofuranophanes, intramolecular hydrogen bond. * Corresponding author. Tel.: +81 952 28 8679; fax: +81 952 28 8548. E-mail address: yamatot@cc.saga-u.ac.jp (T. Yamato) *Revised Manuscript Click here to view linked References © 2017. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/