The Regiospecific Preparation of 2-Substituted Tribenzotriquinacenes

Abstract

Several substituted tribenzotriquinacene derivatives (TBTQ) carrying functional groups exclusively in the 2-position (OMe, OH, Br, CHO, CN, styryl, etc.) have been prepared by our new synthesis of the tribenzotriquinacene framework. The route has been extended to the preparation of a double-cup molecule in which two TBTQ moieties are fused by a benzene ring. The trans configuration of one of the diastereomers of this hydrocarbon was established by X-ray structural analysis.

Key words

cuplike aromatics - Friedel–Crafts cyclizations - cyclo­eliminations - convex molecules - chiral aromatics - double-cup ­structures - single-crystal X-ray structural analysis

• References and Notes

• 1 Markopoulos G, Henneicke L, Shen J, Okamoto Y, Jones PG, Hopf H. Angew. Chem. Int. Ed. 2012; 51: 12884 ; Angew. Chem. 2012, 124, 13057

For the first syntheses of the TBTQ framework, see:
• 2a Kuck D. Angew. Chem. Int. Ed. Engl. 1984; 23: 508 ; Angew. Chem. 1984, 96, 515
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For reviews on centropolyindanes, see:
• 2d Kuck D. Chem. Rev. 2006; 106: 4885
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For some of the rare cases of ortho-substituted TBTQs, see:
• 3a Dullaghan CA, Carpenter GB, Sweigart DA, Kuck D, Fusco C, Curci R. Organometallics 2000; 19: 2233
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• 6 Preparation of the Amine 3g as Typical Experimental Procedure An oven-dried, two-necked round-bottomed flask was charged with 2-bromotribenzotriquinacene (3d, 300 mg, 0.83 mmol), p-toluidine (107 mg, 1.0 mmol), Xanthphos [4,5-bis(diphenylphosphino)-9,9-dimethylxanthene, 29 mg, 0.05 mmol], NaOt-Bu (112 mg, 1.16 mmol), and Pd₂(dba)₃ [tris(dibenzylideneacetone)dipalladium(0), 23 mg, 0.02 mmol]. The flask was evacuated and refilled with argon three times. Toluene (100 mL) was added, and the reaction mixture was refluxed for 20 h. After cooling to r.t., the reaction mixture was diluted with EtOAc and passed through a pad of silica gel. The solvent was removed in vacuo, and the analytically pure amine 3g was obtained by flash chromatography using silica and 5% EtOAc in pentane as the eluent: 220 mg (68%) of 3g, mp 215–216 °C. ¹H NMR (400 MHz, CDCl₃, TMS): δ = 7.46–7.34 (m, 4 H), 7.28 (d, J = 8.0 Hz, 1 H), 7.17–7.13 (m, 5 H), 7.04 (d, J = 8.4 Hz, 2 H), 6.92 (d, J = 8.0 Hz, 2 H), 6.83 (d, J = 8.0 Hz, 1 H), 5.54 (br s, 1 H), 4.95–4.86 (m, 3 H), 4.47 (q, J = 9.6 Hz, 1 H), 2.28 (s, 3 H) ppm. ¹³C NMR (100.6 MHz, CDCl₃): δ = 147.0, 146.2, 145.9, 145.7, 145.6, 143.1, 140.9, 138.2, 130.2, 129.8, 127.3, 127.3, 127.2, 124.7, 124.2, 124.2, 118.0, 117.5, 113.2, 55.8, 55.8, 55.2, 51.6, 20.6 ppm. UV (CH₂Cl₂): λ_max (lg ε) = 228 (4.21), 278 (4.18), 290 (4.25) nm. IR (powder): ν = 3395 (s), 3018 (s), 1606 (m), 1517 (ms), 1492 (m), 1478 (m), 1330 (m), 806 (ms), 742 (vs), 573 (m) cm^–1. MS: m/z calcd: 385.18250; found: 385.18243. Anal. Calcd. for C₂₉H₂₃N (385.50): C, 89.23; H, 6.02; N, 3.58. Found: C, 89.07; H, 6.03; N, 3.27.
• 7 For Rieche formylation reactions of several derivatives of 3a, see: Niu WX, Wang T, Hou QQ, Li ZY, Cao XP, Kuck D. J. Org. Chem. 2010; 75: 6704
• 8 Wang T, Hou QQ, Teng QF, Yao XJ, Niu WX, Cao XP, Kuck D. Chem. Eur. J. 2010; 16: 12412
• 9 Niu WX, Yang EQ, Shi ZF, Cao XP, Kuck D. J. Org. Chem. 2012; 77: 1422
• 10 Kuck D, Schuster A, Krause RA, Tellenbröker J, Exner CP, Penk M, Bögge H, Müller A. Tetrahedron 2001; 57: 3587 ; and references quoted therein
• 11 X-Ray Structure Determination of anti-7 Crystal Data Monoclinic, P2₁/c, a = 10.5987(8), b = 25.6904(16), c = 10.5725(8) Å, β = 104.749(8)°, V = 2783.9(3) ų, Z = 4, μ = 0.5 mm^–1, D _x = 1.252 mg/m³. Data Collection and Reduction A colorless hexagonal plate 0.15 × 0.1 × 0.02 mm was mounted on a glass fiber in inert oil and transferred to the cold gas stream of the diffractometer (Oxford Diffraction Nova A). A total of 53127 intensities were recorded to 2θ_max 152° using mirror-focussed Cu Kα radiation (λ = 1.54184 Å); 5783 of these were independent (R _int = 0.073). Absorption corrections were performed on the basis of multiscans. Structure Refinement The structure was refined anisotropically on F ² using the program SHELXL-97.¹² Hydrogen atoms were included using a riding model starting from calculated positions. The final wR2 for all reflections was 0.134 for 373 parameters, with R1 = 0.049 for reflections with I > 2σ(I); S = 1.02, max. Δρ = 0.58 e Å^–3. Crystallographic data have been deposited with the Cambridge Crystallographic Data Centre as supplementary publication no. CCDC 909301. Copies of the data can be obtained free of charge from www.ccdc.cam.ac.uk/data_request/cif.
• 12 Sheldrick GM. Shelxl-97, Program for the Refinement of Crystal Structures. Universität Göttingen; Göttingen, Germany: 1997. see also: Sheldrick G. M.; Acta Crystallogr., Sect. A: Found. Crystallogr. 2008, 64, 112