J. Liu et al. / Tetrahedron: Asymmetry 19 (2008) 906–911
911
4H), 1.18 (d, J = 6.4 Hz, 3H); 13C NMR (75 MHz, CDCl3):
d = 170.5, 135.0, 128.7, 93.5, 72.9, 69.7, 67.6, 55.3, 44.2,
34.4, 31.3, 21.6; [a]D = +39 (c 0.61, CHCl3). HRMS: m/z
[M+Na]+ calcd: 267.1203; found: 267.1201.
13C NMR (75 MHz, CDCl3): d = 170.2, 138.0, 136.7,
118.1, 117.5, 93.9, 93.6, 76.8, 73.8, 71.1, 55.5, 55.4, 41.1,
31.7, 31.2, 19.9; [a]D = À3 (c 2, CHCl3); HRMS: m/z
[M+Na]+ calcd: 339.1779; found: 339.1782.
4.14. Compound 1
Acknowledgments
To a solution of 16 (10 mg, 0.04 mmol) in 2.5 mL of MeOH
and 0.5 mL of water was added 30 mg of Dowex-50W-X8,
which was treated according to the method reported.16
After the reaction mixture was refluxed for 5 h, the
resin was removed by filtration and washed with MeOH.
The solvent was evaporated, and the residual material
was chromatographed (hexane/EtOAc = 1/2) to give
compound 1 as a white solid (69% yield). 1H NMR
(400 MHz, CD3OD): d = 5.76 (dd, J = 2.4 Hz and
15.6 Hz, 1H), 5.64 (dd, J = 8 Hz and 15.6 Hz, 1H), 4.76–
4.80 (m, 1H), 4.63–4.64 (m, 1H), 4.09–4.14 (m, 1H), 2.54
(dd, J = 3.6 Hz and 11.6 Hz, 1H), 2.49 (dd, J = 3.6 Hz
and 12 Hz, 1H), 1.93–1.98 (m, 1H), 1.75–1.80 (m, 1H),
1.58–1.68 (m, 2H), 1.16 (d, J = 6.8 Hz, 3H); 13C NMR
(100 MHz, CDCl3): d = 170.4, 133.2, 130.5, 74.4, 73.0,
67.0, 44.2, 37.2, 31.4, 20.8; [a]D = À51 (c 0.3, MeOH).
HRMS: m/z [M+Na]+ calcd: 223.0941; found: 223.0943.
We are grateful for the generous financial support by the
Special Doctorial Program Funds of the Ministry of
Education of China (20040730008), NSFC (QT Program,
No. 20572037), NCET-05-0879, the key grant project of
Chinese Ministry of Education (No. 105169), and the
Gansu Science Foundation (3ZS051-A25-004).
References
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4.15. Diene 17a
To a solution of known diol 17c4 (38 mg, 0.17 mmol) in
DMF (3 mL) were added imidazole (116 mg, 1.7 mmol)
and TBSCl (103 mg, 0.68 mmol). After stirring overnight
at rt, EtOAc was added and the mixture was washed with
water twice. The organic was dried over Na2SO4, filtered
and concentrated in vacuo. Purification by flash column
chromatography gave protected diene 17a (70 mg) as a col-
orless oil in 90% yield. 1H NMR (300 MHz, CDCl3):
d = 5.70–5.89 (m, 2H), 5.01–5.24 (m, 4H), 4.83–4.89 (m,
1H), 4.53–4.60 (m, 1H), 4.07–4.09 (m, 1H), 2.51 (dd,
J = 7.5 Hz, 14.4 Hz, 1H), 2.40 (dd, J = 6.3 Hz, 14.7 Hz,
1H), 1.41–1.59 (m, 4H), 1.20 (d, J = 6 Hz, 3H), 0.81–0.84
(m, 18H), 0.02–0.05 (m, 12H); 13C NMR (75 MHz,
CDCl3): d = 170.6, 141.3, 140.3, 114.6, 113.9, 73.5, 71.2,
70.7, 43.9, 33.7, 31.4, 27.4, 25.8, 20.0, 18.2, 13.7, À4.4,
À4.9; [a]D = À4 (c 2.2, CHCl3); HRMS: m/z [M+Na]+
calcd: 479.2983; found: 479.2985.
7. For review of RCM, see (a) Nicolaou, K. C.; Bulger, P. G.;
Sarlah, D. Angew. Chem., Int. Ed. 2005, 44, 4490–4527; (b)
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4.16. Diene 17b
To a solution of alcohol 15 (55 mg, 0.2 mmol) in dry DCM
(5 mL) at room temperature, Hunig’s base (0.23 mL,
1.2 mmol), MOMCl (0.09 mL, 1 mmol), and a catalytic
amount of NaI were added. After stirring for 8 h at rt,
water was added. The organic layer was separated and
the aqueous layer was extracted twice with DCM. The
combined organic extracts were dried over Na2SO4,
filtered, and concentrated in vacuo. Purification by flash
column chromatography gave ether 17b (60 mg, 97% yield)
1
as a colorless oil. H NMR (300 MHz, CDCl3): d = 5.56–
5.76 (m, 2H), 5.15–5.31 (m, 4H), 4.89–4.95 (m, 1H), 4.67
(d, J = 6.9 Hz, 2H), 4.52 (d, J = 6.9 Hz, 2H), 4.42–4.49
(m, 1H), 3.93–3.97 (m, 1H), 3.33 (s, 3H), 3.32 (s, 3H),
2.59 (dd, J = 9.6 Hz, 15 Hz, 1H), 2.45 (dd, J = 5.4 Hz,
15 Hz, 1H), 1.53–1.64 (m, 4H), 1.23 (d, J = 6 Hz, 3H);