反应详情

A stirred solution of ethyl (pentafluorobenzoyl)acetate 1 (5.77 g, 20 mmol), Ac2O (8.02 mL, 8.34 g, 80 mmol) and triethyl orthoformate (5.1 mL, 4.54 g, 30 mmol) was heated at 130° C. for 1.5 h. The mixture was concentrated in vacuo and dried under high vacuum for 3 hours. The crude product 2 was dissolved in anhydrous CH2Cl2 (10 mL) and cyclopropyl amine (2.15 mL, 1.75 g, 30 mmol) was added very slowly at room temperature. After 1.5 h, the solvent was removed by evaporation to yield 3 as a dark yellow solid (7.55 g crude, quantitative) that was used in the next step without further purification.

1. concentrationThe mixture was concentrated in vacuo
2. customdried under high vacuum for 3 hours
3. dissolutionThe crude product 2 was dissolved in anhydrous CH2Cl2 (10 mL)
4. customthe solvent was removed by evaporation