反应详情

温度

-78 °C

To a solution of oxazolidone (2) (30.2 g, 0.234 mol) in 400 mL THF at −78° C. was added n-BuLi (2.5 M in hexanes, 96.0 mL, 0.240 mol) dropwise over a period of 30 min. The solution was stirred at −78° C. for an hour. Heptanoyl chloride (37.15 g, 0.250 mol) was gradually added by syringe and the resulting solution stirred at −78° C. for 1 h and then warmed to 0° C. A saturated aqueous solution of NH4Cl (100 mL) was added and the mixture gradually warmed to room temperature. The mixture was extracted with ethyl acetate (3×20 mL) and the combined organic layers were washed with brine and dried over anhydrous MgSO4. The solvent was removed by a rotary evaporation and the yellowish residue chromatographed on a silica gel column using Hexane/EtOAc (8:1) as the eluant to give 4 as a colorless oil (46.272 g, 0.192 mol, 82%). 1H NMR (400 MHz, CDCl3) δ0.87 (t, J=7.2 Hz, 3 H), 0.88 (d, J=16.9 Hz, 3 H), 0.90 (d, J=16.9 Hz, 3 H), 1.24-1.39 (m, 6 H), 1.59-1.69 (m, 2 H)2.31-2.43 (m, 1 H), 2.81-3.02 (m, 2 H), 4.19-4.29 (m, 2 H), 4.41-4.45 (m, 1 H); 13C NMR (100 MHz, CDCl3) δ13.9, 14.5, 17.9, 22.4, 24.3, 28.3, 28.7, 31.4, 35.4, 58.3, 63.2, 154.0, 173.4.

1. stirringthe resulting solution stirred at −78° C. for 1 h
2. temperaturewarmed to 0° C
3. temperaturethe mixture gradually warmed to room temperature
4. extractionThe mixture was extracted with ethyl acetate (3×20 mL)
5. washthe combined organic layers were washed with brine
6. dry with materialdried over anhydrous MgSO4
7. customThe solvent was removed by a rotary evaporation
8. customthe yellowish residue chromatographed on a silica gel column