A Molecular Cage Accessed by Threefold Click Reaction of a C 3v -Symmetric Triazido-Functionalized Tribenzotriquinacene

• Published in: Journal of organic chemistry 2024-02, Vol.89 (4), p.2127-2137
• Main Authors: Liu, Shuai-Nan, Ren, Qing-Xia, Ding, Yun-Tao, Cao, Xiao-Ping, Shi, Zi-Fa, Chow, Hak-Fun, Kuck, Dietmar
• Format: Article
• Language: English
• ISSN: 0022-3263; 1520-6904
• DOI: 10.1021/acs.joc.3c01349

The hitherto unknown hexakis­(halomethyl)-functionalized tribenzotriquinacenes (TBTQs) 9 and 10 were synthesized from the key 4b,8b,12b-tribromo-TBTQ derivative 6 by an improved route in 67% overall yield. Extension of the bowl-shaped framework of 9 or 10 by threefold condensation with propargylamine or 2-azidoethylamine afforded the corresponding TBTQ-trialkyne 11 and TBTQ-triazide 12, respectively. While attempts to construct bis-TBTQ cages, including homodimerization of 11 and heterocoupling of 11 with 12, were unsuccessful, triazide 12 was found to undergo threefold [3 + 2]-cycloaddition with 3-ethynylaniline and phloroglucinol tripropargyl ether under click chemistry conditions. The latter reaction enabled facile capping of the TBTQ bowl to give the novel cage compound 5 in 22% yield.