反应详情

Potassium carbonate (2.85 g, 20.7 mmol) was added to 3a (500 mg, 2.07 mmol) in N,N-dimethylformamide (4.10 mL) at room temperature. After 10 minutes, 2-iodopropane (2.06 mL, 20.7 mmol) was added and the solution was heated to reflux for 12 hours. Upon cooling to room temperature, the solution was extracted with EtOAc (3×20 mL); combined organic fractions were washed with saturated aqueous NaCl, dried (Na2SO4), filtered, and concentrated. The residue was purified via column chromatography (SiO2, 5:1→1:1 Hexane:EtOAc) to afford 4c as a yellow oil (0.32 g, 55%): 1H NMR (CD2Cl2, 400 MHz) δ 6.87 (s, 1H), 6.86 (d, J=4.9 Hz, 1H), 6.66 (dd, J=11.6, 3.4 Hz, 1H), 5.23 (s, 2H), 5.17 (s, 2H), 4.44-4.38 (m, 1H), 3.83-3.72 (m, 4H), 1.33 (s, 3H), 1.31 (s, 3H), 1.27-1.23 (m, 6H); 13C NMR (CDCl3, 125 MHz) δ 152.4, 149.1, 143.2, 118.6, 109.5, 107.5, 94.4, 93.9, 72.8, 64.3, 64.1, 22.2 (2C), 15.1, 15.1; IR (film) νmax 2976, 1591, 1504, 1528, 1391, 1258, 1217, 1107, 1011, 847 cm−1; HRMS (ESI+) m/z: [M+H]+ calcd for C15H24O5, 285.1702. found, 285.1746; [M+Na]+ calcd for C15H24O5, 307.1522. found, 307.1310.

1. temperaturethe solution was heated
2. temperatureto reflux for 12 hours
3. extractionthe solution was extracted with EtOAc (3×20 mL)
4. washcombined organic fractions were washed with saturated aqueous NaCl
5. dry with materialdried (Na2SO4)
6. filtrationfiltered
7. concentrationconcentrated
8. customThe residue was purified via column chromatography (SiO2, 5:1→1:1 Hexane:EtOAc)