反应详情

A solution of 2a (3.78 g, 12.0 mmol) in anhydrous CH2Cl2 (4.0 mL) was slowly added to mCPBA (70%) (3.26 g, 13.2 mmol) in anhydrous CH2Cl2 (16.3 mL) at 0° C. The resulting solution was warmed to room temperature, then refluxed for 12 hours. After cooling to room temperature, the resulting solution was washed with saturated aqueous NaHCO3 solution (3×20 mL) and 10% aqueous Na2S2O3 (30 mL). Combined organic fractions were dried (Na2SO4), filtered, and concentrated. The residue was re-dissolved in MeOH (5 mL) and stirred with excess 10% aqueous NaOH for three hours at room temperature. The pH was adjusted to 2 with 6 M HCl and the solution was extracted with CH2Cl2 (3×10 mL). Combined organic fractions were dried (Na2SO4), filtered, and concentrated to give 3a as an orange oil (8.21 g, 94%): 1H NMR (CDCl3, 500 MHz) 6.89-6.85 (m, 2H), 6.67 (dd, J=8.8, 2.7 Hz, 1H), 5.81 (d, J=6.6 Hz, 1H), 5.23 (s, 2H), 5.15 (s, 2H), 3.80-3.73 (m, 4H), 1.29-1.24 (m, 6H); 13C NMR (CDCl3, 125 MHz) δ 151.0, 145.0, 141.5, 115.2, 110.6, 106.0, 94.9, 94.2, 64.8, 64.1, 15.1, 15.1; IR (film) νmax 3362, 2887, 1460, 1286, 1162, 735 cm−1; HRMS (ESI+) m/z: [M+Na]+ calcd for C12H18O5, 265.1052; found, 265.1045.

1. temperaturerefluxed for 12 hours
2. temperatureAfter cooling to room temperature
3. washthe resulting solution was washed with saturated aqueous NaHCO3 solution (3×20 mL) and 10% aqueous Na2S2O3 (30 mL)
4. dry with materialCombined organic fractions were dried (Na2SO4)
5. filtrationfiltered
6. concentrationconcentrated
7. dissolutionThe residue was re-dissolved in MeOH (5 mL)
8. extractionthe solution was extracted with CH2Cl2 (3×10 mL)
9. dry with materialCombined organic fractions were dried (Na2SO4)
10. filtrationfiltered
11. concentrationconcentrated