Synlett 2005(2): 343-345  
DOI: 10.1055/s-2004-837220
LETTER
© Georg Thieme Verlag Stuttgart · New York

Short and Efficient Synthesis of Cadiolide B

John Boukouvalas*, Martin Pouliot
Département de Chimie, Université Laval, Québec G1K 7P4, Canada
Fax: +1(418)6567916; e-Mail: john.boukouvalas@chm.ulaval.ca;
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Publikationsverlauf

Received 4 October 2004
Publikationsdatum:
22. Dezember 2004 (online)

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Abstract

The first synthesis of cadiolide B has been achieved in 6 steps and 42% overall yield from 4-bromo-2(5H)-furanone. The pathway involves sequential, regiocontrolled introduction of the three furanone substituents by means of aldol reactions and Suzuki cross coupling.

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Compound 6: yellow oil. 1H NMR (300 MHz, CDCl3): δ = 3.66 (br s, 1 H), 3.79 (s, 3 H), 4.82 (s, 2 H), 5.62 (s, 1 H), 6.89 (d, J = 8.7 Hz, 2 H), 7.38 (d, J = 8.7 Hz, 2 H). 13C NMR (75 MHz, CDCl3): δ = 55.2, 69.0, 73.4, 114.1, 127.1, 132.1, 132.4, 139.3, 159.6, 170.2. Anal. Calcd for C12H11BrO4: C, 48.19; H, 3.71. Found: C, 48.13; H, 3.57.

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Compound 7: white solid; mp 90-92 °C. 1H NMR (300 MHz, CDCl3): δ = 3.78 (s, 3 H), 3.82 (s, 3 H), 4.15 (d, J = 9.8 Hz, 1 H), 5.03 (d, J = 16.9 Hz, 1 H), 5.22 (d, J = 16.9 Hz, 1 H), 5.79 (d, J = 9.8 Hz, 1 H), 6.88 (d, J = 8.6 Hz, 2 H), 6.93 (d, J = 8.8 Hz, 2 H), 7.29 (d, J = 8.8 Hz, 2 H), 7.38 (d, J = 8.6 Hz, 2 H). 13C NMR (75 MHz, CDCl3): d = 55.2, 55.3, 68.4, 70.8, 114.1, 114.6, 122.4, 124.8, 127.7, 129.2, 133.4, 156.8, 159.3, 161.6, 174.6. HRMS: m/z calcd for C19H18O5: 326.1154; found: 326.1158.
Compound 8: yellow solid; mp 166-167 °C. 1H NMR (300 MHz, CDCl3): d = 3.79 (s, 3 H), 3.85 (s, 3 H), 5.30 (s, 2 H), 6.84 (d, J = 8.8 Hz, 2 H), 6.92 (d, J = 8.8 Hz, 2 H), 7.36 (d, J = 8.8 Hz, 2 H), 7.91 (d, J = 8.8 Hz, 2 H). 13C NMR (75 MHz, CDCl3): d = 55.3, 55.5, 70.3, 114.1, 114.6, 121.4, 123.4, 128.7, 129.6, 132.0, 159.7, 162.4, 164.6, 171.1, 190.1. Anal. Calcd for C19H16BrO5: C, 70.36; H, 4.97. Found: C, 70.12; H, 5.02.

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Compound 9: yellow solid; 189-190 °C. 1H NMR (300 MHz, CDCl3): δ = 3.79 (s, 3 H), 3.81 (s, 3 H), 3.84 (s, 3 H), 6.23 (s, 1 H), 6.84 (d, J = 8.6 Hz, 2 H), 6.87 (d, J = 8.6 Hz, 2 H), 6.92 (d, J = 8.6 Hz, 2 H), 7.36 (d, J = 8.6 Hz, 2 H), 7.80 (d, J = 8.6 Hz, 4 H). 13C NMR (75 MHz, CDCl3): δ = 55.2, 55.3, 55.4, 113.7, 114.2, 114.4, 116.8, 121.3, 122.7, 125.7, 129.2, 130.7, 132.0, 132.9, 145.7, 156.8, 160.9, 161.2, 164.1, 166.6, 188.1. HRMS: m/z calcd for C27H22O6: 442.1416; found: 442.1424.

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Compound 10: yellow solid; 262-263 °C. 1H NMR (300 MHz, DMSO-d 6): δ = 6.33 (s, 1 H), 6.77 (d, J = 8.7 Hz, 2 H), 6.80 (d, J = 8.6 Hz, 2 H), 6.88 (d, J = 8.7 Hz, 2 H), 7.23 (d, J = 8.6 Hz, 2 H), 7.70 (d, J = 8.7 Hz, 2 H), 7.75 (d, J = 8.7 Hz, 2 H), 10.06 (br s, 1 H), 10.18 (br s, 1 H), 10.55 (br s, 1 H). 13C NMR (75 MHz, DMSO-d 6): δ = 115.5, 115.8, 116.1, 116.4, 119.5, 121.5, 124.1, 127.5, 130.9, 132.2, 133.1, 144.7, 156.0, 159.4, 159.6, 163.1, 166.1, 188.1. HRMS: m/z calcd for C24H16O6: 400.0947; found: 400.0956.