Synthesis and structure of a chiral areno-bridged [2.4]metacyclophane. Issue 2 (11th January 2018)

• Record Type: Journal Article
• Authors: Akther, Thamina; Islam, Md.Monarul; Matsumoto, Taisuke; Tanaka, Junji; Thuéry, Pierre; Redshaw, Carl; Yamato, Takehiko
• Is Part Of: Tetrahedron. Volume 74:Issue 2(2018)
• Page Start: 329
• Page End: 335
• Publication Date: 2018-01-11
• Subjects: Metacyclophane -- McMurry reaction -- Bromination -- Diels–Alder reaction -- Chirality; Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tet.2017.11.075
• Languages: English
• ISSNs: 0040-4020

Abstract

Abstract: The reductive coupling reaction of 1, 4-bis(3-acetyl-5- tert -butyl-2-methoxyphenyl)butane3 was carried out using TiCl4 -Zn in pyridine followed by a McMurry coupling reaction to afford the compounds anti and syn 1, 2-dimethyl[2.4]MCP-1-ene4 . Bromination of4 with BTMA-Br3 in dry CH2 Cl2 afforded the interesting compound 1, 2-bis-(bromomethyl)-5, 15-di- tert -butyl-8, 18-dimethoxy[2.4]MCP-1-ene6 and consecutive debromination with Zn and AcOH in CH2 Cl2 solution afforded the stable solid 5, 15-di- tert -butyl-8, 18-dimethoxy-1, 2-dimethylene[2.4]MCP7 in 89% yield. Compound7 was conveniently employed in a Diels–Alder reaction with dimethyl acetylenedicarboxylate (DMAD) to provide 2-(3′, 6′-dihydrobenzo)-5, 15-di- tert -butyl-8, 18-dimethoxy[2.4]MCP-4′, 5′-dimethylcarboxylate8 in good yield. Diels–Alder adduct8 was converted into a novel and inherently chiral areno-bridged compound [2.4]MCP9 by aromatization. The chirality of the two conformers was characterized by circular dichroism (CD) spectra of the separated enantiomer which are perfect mirror images of each other. Graphical abstract: The synthesis and chiral properties of an areno-bridged [2.4]MCP via a Diels-Alder reaction from 1, 2-dimethylene[2.4]MCP are discussed.