title: o-Quinones Derived from Tribenzotriquinacenes: Functionalization of Inner Bay Positions and Use for Single-Wing Extensions.
abstract: 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 Cs- 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 Cs-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.
authors.affiliation: State Key Laboratory of Applied Organic Chemistry and College of Chemistry and Chemical Engineering, Lanzhou University , Lanzhou, 730000, P. R. China.
authors.forename: Yu-Fei
authors.initials: YF
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Applied Organic Chemistry and College of Chemistry and Chemical Engineering, Lanzhou University , Lanzhou, 730000, P. R. China.
authors.forename: Wan-Fa
authors.initials: WF
authors.lastname: Tian
authors.affiliation: State Key Laboratory of Applied Organic Chemistry and College of Chemistry and Chemical Engineering, Lanzhou University , Lanzhou, 730000, P. R. China.
authors.forename: Xiao-Ping
authors.initials: XP
authors.lastname: Cao
authors.affiliation: Department of Chemistry and Center for Molecular Materials (CM2), Bielefeld University , 33615 Bielefeld, Germany.
authors.forename: Dietmar
authors.initials: D
authors.lastname: Kuck
authors.affiliation: Department of Chemistry, State Key Laboratory of Synthetic Chemistry and The Center of Novel Functional Molecules, The Chinese University of Hong Kong , Shatin, Hong Kong.
authors.forename: Hak-Fun
authors.initials: HF
authors.lastname: Chow