Synlett 2004(1): 161-164  
DOI: 10.1055/s-2003-43332
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© Georg Thieme Verlag Stuttgart · New York

Radical-Induced Cycloaromatization: Routes to Fluoranthenes and Acephenanthrylenes

John L. Scott, Sean R. Parkin, John E. Anthony*
Department of Chemistry, University of Kentucky, Lexington KY 40506-0055, USA
Fax: +1(859)3231069; e-Mail: anthony@uky.edu;
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Publikationsverlauf

Received 29 August 2003
Publikationsdatum:
04. Dezember 2003 (online)

Abstract

The cycloaromatization of easily-prepared arenediynes is an efficient route to fused aromatic systems, but the requirement of very high temperatures to induce this reaction limits both scalability and generality. We demonstrate that cycloaromatization can be induced by addition of a radical species to an arenediyne unit. Tethering this radical to the enediyne leads to the formation of larger fused systems, such as fluoranthenes and acephenanthrylenes, in a single step.

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For the synthesis of bromoarenediynes, see ref. [8b]

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Details of the crystal structure determination (deposition number CCDC 220601) may be obtained free of charge on application to the CCDC, 12 Union Road, Cambridge CB2 1EZ, UK [fax: +44(1223)336033; e-mail: deposit@ccdc.cam.ac.uk; web: www.ccdc.cam.ac.uk].

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Selected characterization data. Compound 4a (silylated): mp. 110-111 °C (EtOH). 1H NMR (200 MHz, CDCl3): δ = 0.08 (s, 9 H), 0.33 (s, 9 H), 1.35 (s, 9 H), 7.20-7.25 (m, 1 H), 7.30 (d, J = 2.2 Hz, 1 H), 7.34 (s, 1 H), 7.36 (s, 1 H), 7.56 (d, J = 2.2 Hz, 1 H), 7.68 (d, J = 7.6 Hz, 1 H) ppm. 13C NMR (50 MHz, CDCl3): δ = -0.34, -0.04, 30.97, 34.75, 97.52, 101.64, 101.98, 104.04, 122.75, 123.29, 125.27, 126.58, 127.18, 128.29, 128.84, 131.43, 132.41, 141.58, 144.20, 150.68 ppm. FTIR (KBr): 3052.63, 2955.33, 2893.88, 2151.35, 1244.95, 871.12, 840.40 cm-1. HRMS: m/z (%) calcd for C22H33BrSi2: 480/482. Found: 482.1284(20) [M + 2], 480.1304(25) [M+], 467(80) [M+ - CH3]. Compound 5a: 1H NMR (200 MHz, CDCl3): δ = 1.43 (s, 9 H), 7.34-7.45 (m, 4 H), 7.55-7.63 (m, 1 H), 7.77-7.81 (m, 1 H), 7.85-7.95 (m, 2 H), 8.06 (d, J = 2 Hz, 1 H) ppm. 13C NMR (100 MHz, CDCl3): δ = 29.69, 31.65, 119.03, 119.32, 121.37, 121.54, 121.81, 123.05, 125.47, 125.79, 126.51, 127.06, 127.37, 127.95, 128.96, 132.12, 132.81, 151.38 ppm. HRMS: m/z (%) calcd for C20H18: 258.1409. Found: 258.1403(65) [M+], 243(100) [M+ - CH3]. Anal. Calcd for C20H18: C, 92.97%; H, 7.02%. Found: C, 92.74%; H, 7.03%. Compound 6c: Yellow oil. 1H NMR (200 MHz, CDCl3): δ = 1.75 (s, 9 H), 7.22 (m, 7 H), 7.31 (d, J = 7 Hz, 1 H), 7.33 (m, 5 H), 7.35 (d, J = 8 Hz, 1 H), 7.55 (d, J = .5 Hz, 1 H), 7.67 (d, J = 7 Hz, 1 H) ppm. 13C NMR (50 MHz, CDCl3): δ = 30.96, 34.76, 87.51, 89.06, 93.11, 96.38, 115.16, 120.18, 121.90, 122.81, 123.33, 123.42, 125.49, 125.55, 126.74, 126.81, 127.24, 127.87, 127.91, 128.10, 128.32, 129.04, 131.26, 131.55, 131.59, 131.77, 132.57, 141.60, 143.44, 150.67 ppm. MS (EI, 70 eV): m/z (%) = 488(10) [M+], 473(80) [M+ - CH3]. Anal. Calcd for C32H25Br: C, 78.52%; H, 5.14%. Found: C, 78.33%; H, 4.90%. Compound 7: mp 170-171 °C (MeOH). 1H NMR (200 MHz, CDCl3): δ = 1.82 (s, 9 H), 7.25 (m, 6 H), 7.37 (m, 5 H), 7.51 (s, 1 H), 7.73 (t, J = 8 Hz, 1 H), 7.95 (t, J = 8 Hz, 1 H), 8.11 (d, J = 7 Hz, 1 H), 8.71 (s, 1 H), 9.03 (d, J = 8 Hz, 1 H) ppm. 13C NMR (50 MHz, CDCl3): δ = 31.81, 35.65, 116.57, 120.74, 122.85, 125.20. 125.98, 126.20, 127.02, 127.19, 127.27, 127.38, 128.34, 128.93, 131.21, 131.49, 131.56, 134.25, 136.93, 137.19, 138.50, 138.92, 145.23, 151.51 ppm. MS: m/z (%) calcd for C32H26: 410.2035. Found: 410.2035(20) [M+], 395(100) [M+ - CH3].