反应详情

Prepared using a procedure adapted from Miyazawa et al. (Miyazawa, E.; et al. Org. Prep. Proced. Int. 1997, 29, 594-600) tBuOK (0.78 g, 6.7 mmol) was added to a stirring solution of ethyl-N-hydroxyacetimidate (1.00 g, 6.06 mmol) in anhydrous DMF (6 mL) at 0° C. under an Ar atmosphere. After tBuOK addition was completed the reaction was stirred at room temperature. After 30 min 2-fluorobenzotrifluoride (1.29 mL, 6.06 mmol) was added and the reaction was heated at 80° C. for 2 h. Upon cooling the reaction mixture was diluted with ice water (100 mL) and extracted with EtOAc (3×40 mL). The combined organic layers were washed with brine (2×50 mL), dried with MgSO4, and concentrated to afford a dark oil. Flash chromatographic purification over silica (10% EtOAc in hexanes) afforded 15 as a clear liquid (1.33 g, 89%). 1H-NMR (500 MHz, CDCl3) δ 1.36 (t, J=7.1 Hz, 3H), 2.15 (s, 3H), 4.20 (q, J=7.1 Hz, 2H), 6.99 (apparent t, J=7.5 Hz, 1H), 7.47 (apparent dt, J=7.9 Hz, 1H), 7.52-7.57 (m, 2H); 13C-NMR (125 MHz, CDCl3) δ 14.3, 14.5, 63.2, 114.2, 116.2 (q, JC-F=31 Hz), 120.3, 123.7 (q, JC-F=272 Hz), 126.4 (q, JC-F=4.8 Hz), 133.2, 157.2 (q, JC-F=1.9 Hz), 167.1; LC-MS 248 m/z[MH]+, C11H13F3NO2 requires 248.

1. customPrepared
2. temperaturethe reaction was heated at 80° C. for 2 h
3. temperatureUpon cooling the reaction mixture
4. extractionextracted with EtOAc (3×40 mL)
5. washThe combined organic layers were washed with brine (2×50 mL)
6. dry with materialdried with MgSO4
7. concentrationconcentrated
8. customto afford a dark oil
9. customFlash chromatographic purification over silica (10% EtOAc in hexanes)