o-Quinones Derived from Tribenzotriquinacenes: Functionalization of Inner Bay Positions and Use for Single-Wing Extensions

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• 作者：Yu-Fei Zhang ; Wan-Fa Tian ; Xiao-Ping Cao ; Dietmar Kuck ; Hak-Fun Chow
• 刊名：Journal of Organic Chemistry
• 出版年：2016
• 出版时间：March 18, 2016
• 年：2016
• 卷：81
• 期：6
• 页码：2308-2319
• 全文大小：651K
• ISSN：1520-6904

文摘

Through a surprisingly nonregioselective oxidation process, the reaction of two analogous 2-hydroxy-substituted tribenzotriquinacenes (TBTQs) 8a/8b by o-iodoxybenzoic acid was found to afford the corresponding C_s- and C₁-symmetrical TBTQ-o-quinones 6a/6b and 7a/7b, respectively, in 1:1 ratio and excellent combined yields. This finding represents the first example of direct introduction of a functional group into a sterically hindered, inner bay-positions of a parent TBTQ skeleton. In contrast, the analogous reaction with 1-hydroxy-TBTQ 15 failed to produce the desired o-quinone 7a. After reduction of the quinones 6a and 7a to the corresponding catechols 17 and 23, electrophilic aromatic substitution could also be realized at the activated inner bay-position(s) to afford several tri- and tetrafunctionalized TBTQ compounds 18, 21, and 25. The C_s-symmetrical o-quinone 6a was converted into further single-wing extended derivatives such as TBTQ-based phenazines 27a–f, through condensation reactions, and to benzodioxine derivative 32 by Diels–Alder reaction with tetracyclone. The novel TBTQ-quinones and the corresponding TBTQ-catechols offer a variety of new accesses to single-wing-extended and -functionalized TBTQ derivatives.