Angewandte
Chemie
Table 1: Selected data for compounds 1, 14, 15, and 19.
1: Rf =0.11 (SiO2, EtOAc/cyclohexane (1:3)); 1H NMR (400 MHz, CDCl3,
258C): d=9.28 (s, 1H), 8.59 (s, 1H), 7.11 (dd, 1H, J=14.7, 12.3 Hz),
6.66 (s, 1H), 6.31 (t, 1H, J=10.4 Hz), 6.10 (d, 1H, J=16.1 Hz), 5.91 (m,
1H), 5.78 (t, 1H, J=9.9 Hz), 5.22 (d, 1H, J=15.8 Hz), 4.92 (t, 1H,
J=9.1 Hz), 3.96 (d, 1H, J=15.8 Hz), 3.95 (m, 1H), 2.48 (dd, 1H,
J=15.8, 10.7 Hz), 2.13 (m, 1H), 1.54 ppm (d, 3H, J=6.4 Hz); 1H N MR
(400 MHz, [D6]DMSO, 258C): d=10.58 (s, 1H), 10.13 (s, 1H), 7.12 (dd,
1H, J=16.1, 11.3 Hz), 6.56 (s, 1H), 6.27 (t, 1H, J=10.8 Hz), 6.04 (d,
1H, J=16.1 Hz), 5.78 (t, 1H, J=10.8 Hz), 5.46 (d, 1H, J=5.4 Hz), 5.28
(m, 1H), 5.10 (dd, 1H, J=9.9, 4.8 Hz), 4.05 (d, 1H, J=16.1 Hz), 3.99
(m, 1H), 3.60 (d, 1H, J=16.1 Hz), 1.90–1.84 (m, 2H), 1.37 ppm (d, 3H,
J=6.2 Hz); 13C NMR (125 MHz, [D6]DMSO, 258C): d=197.0, 166.5,
155.5, 139.1, 137.0, 133.2, 132.1, 129.9, 115.1, 112.2, 102.9, 71.1, 69.5,
60.8, 44.9, 37.8, 19.0 ppm; HRMS (ESI-TOF): calcd for C18H18Cl2O6
[M+Na+]: 422.9995; found: 423.0337
1
14: Rf =0.19 (SiO2, EtOAc/cyclohexane (1:3)); H NMR (400 MHz,
CDCl3, 258C): d=7.68 (dd, 1H, J=16.1, 11.3 Hz), 6.75 (d, 1H,
J=2.1 Hz), 6.59 (d, 1H, J=2.1 Hz), 6.26 (t, 1H, J=11.3 Hz), 6.05 (d,
1H, J=16.1 Hz), 5.84 (dd, 1H, J=10.8 Hz, 4.4 Hz), 5.42–5.33 (m, 1H),
5.21–5.17 (m, 2H), 5.14 (s, 2H), 3.97 (d, 1H, J=14.0 Hz), 3.86 (d, 1H,
J=13.4 Hz), 3.57 (m, 1H), 3.48 (s, 3H), 3.47 (s, 3H), 3.10–3.13 (ddd,
1H, J=7.5, 3.7, 2.2 Hz), 2.47 (dt, 1H, J=14.5, 4.8 Hz), 1.73 (ddd, 1H,
J=15.0, 7.5, 3.2 Hz), 1.59 ppm (d, 3H, J=6.4 Hz); 13C NMR (100 MHz,
CDCl3, 258C): d=197.9, 166.8, 159.2, 156.0, 140.2, 136.6, 134.5, 131.8,
130.2, 117.8, 108.7, 102.1, 94.6, 94.3, 69.8, 56.3, 55.8, 54.9, 42.4, 37.1,
29.7 18.9 ppm; HRMS (ESI-TOF): calcd for C22H26O8 [M+Na+]:
441.1520; found: 441.1595
1
15: Rf =0.25 (SiO2, EtOAc/cyclohexane (1:1)); H NMR (400 MHz,
CDCl3, 258C): d=7.18 (dd, 1H, J=16.2, 11.2 Hz), 7.04 (s, 1H), 6.26 (t,
1H, J=10.9 Hz), 6.10 (d, 1H, J=16.4 Hz), 5.81 (t, 1H, J=10.2 Hz), 5.47
(m, 1H), 5.35–5.12 (m, 6H), 4.11 (d, 1H, J=15.8 Hz), 3.92 (d, 1H,
J=15.8 Hz), 3.56–3.48 (m, 2H), 3.55 (s, 3H), 3.53 (s, 3H), 1.57 ppm (d,
3H, J=6.4 Hz); 13C NMR (100 MHz, CDCl3, 258C): d=196.3, 166.7,
159.3, 156.0, 140.8, 137.9, 134.7, 133.2, 131.2, 117.8, 102.0, 95.2, 94.6,
71.9, 69.7, 60.4, 56.7, 56.4, 45.1, 21.0, 18.8 ppm; HRMS (ESI-TOF): calcd
for C22H26Cl2O8 [M+Na+]: 510.9994; found: 511.0002
Scheme 4. Synthesis of pochonin C (1) from alcohol 4a. a) PhSH
(1.2 equiv), K2CO3 (1.5 equiv), DMF, 238C, 3 h, 98%; b) LDA
(1.0 equiv), HMPA (1.0 equiv), AllBr (1.1 equiv), THF, ꢀ78!238C,
3 h, 82%; c) 4a (1.0 equiv), P(mClPh)3 (2.0 equiv), DIAD (2.0 equiv),
toluene, 238C, 3 h, 84%; d) MOMCl (4.0 equiv), DIPEA (4.0 equiv),
TBAI (cat.), DMF, 808C, 3 h, 91%; e) LDA (2.0 equiv), THF, ꢀ788C, 5
(1.0 equiv), 81%; f) H2O2 (2.0 equiv), (CF3)2CHOH, 238C, 3 h; then,
toluene, 808C, 1 h, 92%; g) second-generation Grubbs catalyst
(5 mol%), toluene (2 mm), 1208C, 10 min, 87%; h) SO2Cl2 (3.0 equiv),
Et2O, 08C, 68%; i) HCl (conc.; 2.5% in dioxane), 238C, 3 h, 74%;
j) second-generation Grubbs catalyst (5 mol%), toluene (2 mm),
1208C, 10 min, 94%; k) H2O2 (2.0 equiv), (CF3)2CHOH, 238C, 3 h;
then, toluene, 808C, 1 h, 22% (85% based on recovered sulfoxide);
l) nBu3SnH (5.0 equiv), AIBN(cat.), toluene, microwave at 300 W,
10 min, 91%. AIBN=2,2’-azobisisobutyronitrile, DIAD=diisopropyl-
azodicarboxylate, DIPEA=diisopropylethylamine, HMPA=hexamethyl-
phosphoramide, LDA=lithium diisopropylamide, MOM=methoxy-
methyl, second-generation Grubbs catalyst=[ruthenium{1,3-bis-(2,4,6-
trimethylphenyl)-2-imidazolidinylidene}dichloro (phenylmethylene)(tri-
cyclohexylphosphane)], TBAI=tetrabutylammonium iodide.
1
19: Rf =0.19 (SiO2, EtOAc/cyclohexane (1:3)); H NMR (400 MHz,
CDCl3, 258C): d=7.66 (dd, 1H, J=15.8, 10.8 Hz), 6.75 (s, 1H), 6.58 (s,
1H), 6.25 (t, 1H, J=9.7 Hz), 6.04 (d, 1H, J=15.8 Hz), 5.83 (dd, 1H,
J=10.8 Hz, 4.3 Hz), 5.37 (m, 1H), 5.20–5.16 (m, 2H), 5.13 (s, 2H), 3.96
(d, 1H, J=13.7 Hz), 3.85 (d, 1H, J=13.7 Hz), 3.56 (brs, 1H), 3.48 (s,
3H), 3.46 (s, 3H), 3.11–3.09 (m, 1H), 2.49–2.42 (ddd, 1H, J=15.2, 5.1,
4.3 Hz), 1.73–1.68 (ddd, 1H, J=15.2, 7.2, 3.0 Hz), 1.58 ppm (d, 3H,
J=6.3 Hz); 13C NMR (100 MHz, CDCl3, 258C): d=197.8, 166.8, 159.2,
156.1, 140.1, 136.6, 132.8, 131.8, 130.2, 114.2, 108.7, 102.1, 94.6, 94.3,
69.8, 56.3, 55.7, 54.9, 42.4, 37.1, 29.7 18.8 ppm; HRMS (ESI-TOF): calcd
for C22H26O8 [M+Na+]: 441.1520; found: 441.1599
Scheme 5. Conversion of pochonin C (1) into radicicol (2). K2CO3
(2.0 equiv), DMF, 238C, 1 h, 86%.
aromatic ring was observed).[8,23] Final deprotection of the
MOM groups from 15 led to compound 1 (Table 1), which was
found to have identical NMR spectra to pochonin C.[24]
Importantly, treatment of compound 1 with K2CO3 led to
rapid and clean oxirane formation to yield compound 2, which
was identical to radicicol (Scheme 5).
A similar reaction sequence starting from alcohol 4b and
toluic acid 3 led to the triene 18. Treatment of this compound
with the successful metathesis conditions used for 13 afforded
Angew. Chem. Int. Ed. 2004, 43, 3467 –3470
ꢀ 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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