反应详情

To a solution of Intermediate 53a (445 mg, 1.13 mmol) in EtOAc (4 mL) and 1N sodium hydroxide solution (2.40 mL, 2.40 mmol) was added 2,2,2-trichloroethyl chloroformate (165 μL, 1.20 mmol), and the mixture stirred vigorously at RT for 1.5 h. The aqueous layer was extracted with EtOAc (2×10 mL), and then the combined organics dried and concentrated in vacuo. The residue was purified by FCC, using 0-30% EtOAc in cyclohexane, to give the title compound (650 mg, 100%). LCMS (Method 3): Rt 4.90 min, m/z 568, 570, 572 [MH+].

1. extractionThe aqueous layer was extracted with EtOAc (2×10 mL)
2. customthe combined organics dried
3. concentrationconcentrated in vacuo
4. customThe residue was purified by FCC