反应详情

To a mixture of Intermediate 108a (1.29 g, 3.87 mmol) in water (5 mL) and EtOAc (13 mL) was added NaOH (310 mg, 7.74 mmol). After 10 min stirring, 2,2,2-trichloroethyl chloroformate (640 μL, 4.65 mmol) was added and the reaction mixture was stirred at RT for 1 h. The aqueous layer was extracted with EtOAc (×3) and the combined organic layers were washed with brine, dried (MgSO4) and concentrated in vacuo. The resultant residue was purified by FCC on silica, using a gradient of 0-75% EtOAc in cyclohexane, to afford the title compound (1.24 g, 63%). LCMS (Method 4): Rt 3.92 min, m/z 508, 510 [MH+].

1. stirringthe reaction mixture was stirred at RT for 1 h
2. extractionThe aqueous layer was extracted with EtOAc (×3)
3. washthe combined organic layers were washed with brine
4. dry with materialdried (MgSO4)
5. concentrationconcentrated in vacuo
6. customThe resultant residue was purified by FCC on silica