反应详情

温度

40 °C

A mixture of 90% formic acid (26.4 mL, 689 mmol) and 30% hydrogen peroxide (6.0 mL, 39.2 mmol) was warmed at 40° C. for 10 min. The resulting solution was carefully added to 1-cyclopentenyl-2,4-difluorobenzene (7.064 g, 39.2 mmol) under stirring. The two-phase system was initially stirred at room temperature. After a certain period of time, a spontaneous exothermic reaction took place, and the temperature rose to about 50° C. The reaction mixture was stirred at room temperature for 2 h. The reaction mixture was quenched by careful addition of a saturated sodium bicarbonate solution. Ether was added and the content of the separatory funnel was vigorously shaken. The organic layer was separated and the aqueous layer was extracted with ether. The combined organic extracts were dried over anhydrous magnesium sulfate and filtered. The solvent was removed in vacuum and the residue was purified by column chromatography on silica gel to give 2-(2,4-difluorophenyl)cyclopentanone (3.503 g, 17.85 mmol, 45.5% yield) as colorless oil. LC-MS (M+H)+=195.2. 1H NMR (500 MHz, CDCl3) δ ppm 7.08 (1H, td, J=8.4, 6.4 Hz), 6.76-6.86 (2H, m), 3.42 (1H, dd, J=12.2, 8.9 Hz), 2.42-2.53 (2H, m), 2.28-2.39 (1H, m), 2.13-2.23 (1H, m), 1.86-2.10 (2H, m).

1. stirringThe two-phase system was initially stirred at room temperature
2. waitAfter a certain period of time
3. customa spontaneous exothermic reaction
4. customrose to about 50° C
5. stirringThe reaction mixture was stirred at room temperature for 2 h
6. customThe reaction mixture was quenched by careful addition of a saturated sodium bicarbonate solution
7. additionEther was added
8. stirringthe content of the separatory funnel was vigorously shaken
9. customThe organic layer was separated
10. extractionthe aqueous layer was extracted with ether
11. dry with materialThe combined organic extracts were dried over anhydrous magnesium sulfate
12. filtrationfiltered
13. customThe solvent was removed in vacuum
14. customthe residue was purified by column chromatography on silica gel