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Synlett 2012; 23(20): 2939-2942
DOI: 10.1055/s-0032-1317541
letter
© Georg Thieme Verlag Stuttgart · New York

Synthesis of Hemitectol, Tectol, and Tecomaquinone I

Melissa M. Cadelis
School of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand   Fax: +64(9)3737422   Email: b.copp@auckland.ac.nz
,
David Barker
School of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand   Fax: +64(9)3737422   Email: b.copp@auckland.ac.nz
,
Brent R. Copp*
School of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand   Fax: +64(9)3737422   Email: b.copp@auckland.ac.nz
› Author Affiliations
Further Information

Publication History

Received: 06 September 2012

Accepted after revision: 17 October 2012

Publication Date:
13 November 2012 (online)

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Abstract

The first total syntheses of Tectona grandis (teak) natural products hemitectol and tectol are described. The observation of spontaneous dimerisation of hemitectol to tectol suggests the monomer is the true natural product and that the dimer is an artifact of isolation.

Key words

cyclisation - dimerisation - quinone - ring closure - total synthesis
 

  • References and Notes

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  • 5 tert-Butyl(4-methoxynaphthalen-1-yloxy)dimethylsilane (8) IR (ATR): 2929, 2857, 1625, 1596, 1461, 1384, 1273, 1095 cm–1. 1H NMR (400 MHz, CDCl3): δ = 8.25–8.23 (m, 2 H, H-5, H-8), 7.60–7.56 (m, 2 H, H-6, H-7), 6.86 (d, J = 8.5 Hz, 1 H, H-3), 6.73 (d, J = 8.5 Hz, 1 H, H-2), 4.03 (s, 3 H, OCH3), 1.20 (s, 9 H, H-4′, H-5′, H-6′), 0.36 (s, 6 H, H-1′, H-2′). 13C NMR (100 MHz, CDCl3): δ = 149.9 (C-1), 145.2 (C-4), 128.6 (ArC), 126.6 (ArC), 125.8 (ArCH), 125.5 (ArCH), 122.5 (ArCH), 122.0 (ArCH), 111.9 (C-3), 103.5 (C-2), 55.7 (OCH3), 26.0 (C-4′, C-5′, C-6′), 18.5 (C-3′), –4.2 (C-1′, C-2′). ESI-HRMS: m/z calcd for C17H25O2Si [MH+]: 289.1618; found: 289.1624.
  • 6 4-(tert-Butyldimethylsiloxy)naphthalene-1-ol (9) IR (ATR): 3255, 2929, 1595, 1471, 1347, 1266, 1069 cm–1. 1H NMR (400 MHz, CDCl3): δ = 8.10–8.09 (m, 2 H, H-5, H-8), 7.50–7.47 (m, 2 H, H-6, H-7), 6.68 (s, 2 H, H-2, H-3), 1.09 (s, 9 H, H-4′, H-5′, H-6′), 0.24 (s, 6 H, H-1′, H-2′). 13C NMR (100 MHz, CDCl3): δ = 145.4 (C-1), 138.7 (C-4), 126.4 (2 × Ar-C), 125.7 (ArCH), 125.5 (ArCH), 122.7 (ArCH), 121.5 (ArCH), 112.0 (C-2), 108.3 (C-3), 25.9 (C-4′, C-5′, C-6′), 18.4 (C-3′), –4.3 (C-1′, C-2′). ESI-HRMS: m/z calcd for C16H23O2Si [MH+]: 275.1462; found: 275.1462.
  • 7 Lee YR, Kim YM. Helv. Chim. Acta 2007; 90: 2401
    Crossref
  • 8 tert-Butyl(2,2-dimethyl-2H-benzo[h]chromen-6-yloxy)dimethylsilane (10) IR (ATR): 2930, 1595, 1457, 1409, 1370, 1274, 1084 cm–1. 1H NMR (400 MHz, CDCl3): δ = 8.15–8.03 (m, 2 H, H-7, H-10), 7.43–7.40 (m, 2 H, H-8, H-9), 6.54 (s, 1 H, H-5), 6.35 (d, J = 9.7 Hz, 1 H, H-4), 5.63 (d, J = 9.7 Hz, 1 H, H-3), 1.49 (s, 6 H, H-11, H-12), 1.08 (s, 9 H, H-4′, H-5′, H-6′), 0.24 (s, 6 H, H-1′, H-2′). 13C NMR (100 MHz, CDCl3): δ = 144.8 (C-6), 142.4 (C-10b), 129.9 (C-3), 128.3 (ArC), 126.0 (ArC), 125.5 (ArCH), 125.3 (ArCH), 122.9 (C-4), 122.5 (ArCH), 121.8 (ArCH), 115.0 (C-4a), 110.9 (C-5), 76.2 (C-2), 27.6 (C-11, C-12), 25.9 (C-4′, C-5′, C-6′), 18.4 (C-3′), –4.2 (C-1′, C-2′). ESI-HRMS: m/z calcd for C21H29O2Si [MH+]: 341.1931; found: 341.1919.
  • 9 Hemitectol (6) Dark yellow oil. IR (ATR): 3419, 2973, 1586, 1451, 1402, 1369, 1360, 1257, 1070 cm–1. 1H NMR (400 MHz, DMSO-d 6): δ = 8.03–7.96 (m, 2 H, H-7, H-10), 7.46–7.37 (m, 2 H, H-8, H-9), 6.60 (s, 1 H, H-5), 6.43 (d, J = 9.5 Hz, 1 H, H-4), 5.75 (d, J = 9.5 Hz, 1 H, H-3), 1.42 (s, 6 H, H-11, H-12). 13C NMR (100 MHz, DMSO-d 6): δ = 146.4 (C-6), 143.7 (C-10b), 130.4 (C-3), 125.6 (ArCH), 125.1 (ArC), 124.9 (ArC), 124.7 (ArCH), 122.6 (C-4), 122.1 (ArCH), 121.1 (ArCH), 115.2 (C-4a), 105.9 (C-5), 75.7 (C-2), 27.1 (C-11, C-12). ESI-HRMS: m/z calcd for C15H15O2 [MH+]: 227.1067; found: 227.1063.
  • 10 Tectol (5) White solid; 206–209 °C (lit.2 207–208 °C). IR (ATR): 3420, 2973, 1586, 1451, 1402, 1369, 1361, 1221, 1071 cm–1. 1H NMR (400 MHz, DMSO-d 6): δ = 8.17–8.08 (m, 4 H, H-7, H-7′, H-10, H-10′), 7.52–7.44 (m, 4 H, H-8, H-8′, H-9, H-9′), 5.78 (d, J = 9.9 Hz, 2 H, H-4, H-4′), 5.59 (d, J = 9.9 Hz, 2 H, H-3, H-3′), 1.45 (s, 6 H, H-11, H-11′), 1.43 (s, 6 H, H-12, H-12′). 13C NMR (100 MHz, DMSO-d 6): δ = 144.1 (C-6, C-6′), 140.6 (C-10b, C-10b′), 130.0 (C-3, C-3′), 125.5 (2 × ArC), 125.4 (2 × ArCH), 125.1 (2 × ArC), 125.0 (2 × ArCH), 122.5 (2 × ArCH), 121.2 (2 × ArCH), 120.9 (C-4, C-4′), 115.9 (C-4a, C-4a′), 113.2 (C-5, C-5′), 75.2 (C-2, C-2′), 27.0 (C-11, C-11′, C-12, C-12′). ESI-HRMS: m/z calcd for C30H26O4Na [MNa+]: 473.1723; found: 473.1714.
  • 11 Bandaranayake WM, Crombie L, Whiting DA. J. Chem. Soc. 1971; 811
  • 12 Tecomaquinone I (4) Green solid; mp 187–189 °C (lit.2 188–189 °C). IR (ATR): 3360, 2978, 1690, 1568, 1277, 1237, 1197, 1109 cm–1. 1H NMR (400 MHz, DMSO-d 6): δ = 8.14–8.09 (m, 2 H, H-7, H-10), 8.07–8.05 (m, 1 H, H-2′), 8.04–8.01 (m, 1 H, H-5′), 7.95–7.86 (m, 2 H, H-3′, H-4′), 7.65–7.60 (m, 1 H, H-9), 7.57–7.53 (td, J = 7.0, 1.5 Hz, 1 H, H-8), 6.36 (d, J = 9.9 Hz, 1 H, H-4), 6.34 (d, J = 9.1 Hz, 1 H, H-7′), 5.62 (d, J = 9.9 Hz, 1 H, H-3), 5.44 (td, J = 9.0, 1.5 Hz, 1 H, H-8′), 2.03 (br s, 3 H, H-11′), 1.60 (s, 3 H, H-12), 1.59 (s, 3 H, H-10′), 1.55 (s, 3 H, H-11). 13C NMR (100 MHz, DMSO-d 6): δ = 182.8 (C-6′), 181.6 (C-1′), 146.5 (C-6), 142.4 (C-10b), 141.7 (C-9′), 135.9 (ArC), 135.4 (ArC), 134.0 (ArC), 133.8 (2 × ArCH), 132.9 (ArC), 131.3 (ArC), 128.2 (ArCH), 126.7 (ArCH), 126.5 (ArCH), 125.3 (ArCH), 125.3 (C-3), 124.7 (ArC), 123.8 (C-4), 122.5 (ArCH), 121.8 (ArCH), 117.6 (C-8′), 113.0 (C-4a), 111.2 (C-5), 75.5 (C-2), 67.3 (C-7′), 28.2 (C-12), 25.5 (C-10′), 25.2 (C-11), 18.7 (C-11′). ESI-HRMS: m/z calcd for C30H25O4 [MH+]: 449.1747; found: 449.1726.
  • 13 Gonzalez AG, Barroso JT, Cardona RJ, Medina JM, Luis FR. An. Quim. 1977; 73: 538
  • 14 Tohma H, Morioka H, Takizawa S, Arisawa M, Kita Y. Tetrahedron 2001; 57: 345
    Crossref
  • 15 Furan Dimer A (13) Brown solid; mp 112.1–115.1 °C. IR (ATR): 2938, 1637, 1598, 1457, 1382, 1100 cm–1. 1H NMR (400 MHz, CDCl3): δ = 8.18–8.17 (m, 4 H, H-8, H-8′, H-9, H-9′), 7.52–7.46 (m, 4 H, H-7, H-10, H-7′, H-10′), 6.77 (s, 2 H, H-5, H-5′), 4.94 (d, J = 6.5 Hz, 2 H, H-4, H-4′), 3.97 (s, 6 H, OCH3, OCH3′), 2.63 (d, J = 6.5 Hz, 2 H, H-3, H-3′), 1.57 (s, 6 H, H-11, H-11′), 1.46 (s, 6 H, H-12, H-12′). 13C NMR (100 MHz, CDCl3): δ = 149.7 (C-6, C-6′), 142.8 (C-10b, C-10b′), 126.3 (2 × ArC), 126.3 (2 × ArC), 126.0 (2 × ArCH), 126.0 (2 × ArCH), 122.0 (2 × ArCH), 121.8 (2 × ArCH), 115.4 (C-4a, C-4a′), 77.3 (C-2, C-2′), 73.1 (C-4, C-4′), 55.8 (OCH3, OCH3′), 49.4 (C-3, C-3′), 27.9 (C-12, C-12′), 26.9 (C-11, C-11′). ESI-HRMS: m/z calcd for C32H33O5 [MH+]: 497.2323; found: 497.2307.
  • 16 Furan Dimer B (14) Brown solid; mp 216.0–218.6 °C. IR (ATR): 2938, 1637, 1598, 1457, 1382, 1100 cm–1. 1H NMR (400 MHz, CDCl3): δ = 8.23–8.15 (m, 4 H, H-7, H-7′, H-10, H-10′), 7.52–7.42 (m, 4 H, H-8, H-8′, H-9, H-9′), 7.06 (s, 1 H, H-5), 6.96 (s, 1 H, H-5′), 5.13 (d, J = 8.3 Hz, 1 H, H-4), 4.88 (d, J = 10.5 Hz, 1 H, H-4′), 4.07 (s, 3 H, OCH3), 4.01 (s, 3 H, OCH3′), 2.74 (t, J = 8.3 Hz, 1 H, H-3), 2.10 (dd, J = 10.5, 8.3 Hz, 1 H, H-3′), 1.70 (s, 3 H, H-12′), 1.64 (s, 3 H, H-11), 1.60 (s, 3 H, H-11′), 1.17 (s, 3 H, H-12). 13C NMR (100 MHz, CDCl3): δ = 150.0 (C-6′), 149.1 (C-6), 141.5 (C-10b), 141.0 (C-10b′), 126.6 (2 × ArCH), 126.1 (2 × ArCH), 125.9 (ArC), 125.9 (ArC), 125.5 (ArC), 125.1 (ArC), 122.0 (ArCH), 121.9 (2 × ArCH), 121.6 (ArCH), 119.8 (C-4a′), 116.6 (C-4a), 102.8 (C-5), 99.4 (C-5′), 80.6 (C-2′), 77.8 (C-4), 76.6 (C-2′), 76.2 (C-4′), 56.0 (OCH3), 55.8 (OCH3′), 55.6 (C-3′), 49.6 (C-3), 31.7 (C-12′), 29.9 (C-11), 24.0 (C-11′), 22.6 (C-12). ESI-HRMS: m/z calcd for C32H33O5 [MH+]: 497.2323; found: 497.2305.
  • 17 Fraga BM, Garcia VP, Gonzalez AG, Hernandez MG, Hanson JR, Hitchcock PB. J. Chem. Soc. 1983; 2687