反应详情

1 g (5.68 mmol) 2-bromo-5-fluoropyridine, 160 mg dichlorobis(triphenylphosphine) palladium and 170 mg CuI were suspended in baked flasks under protective gas in 30 ml acetonitrile, 6.09 g (16.87 mmol) (1-ethoxyvinyl)-tributylstannane were added, the mixture was heated 8 hours at reflux, 200 ml 1.5 n HCl were subsequently added and reflux was continued for an additional hour. For workup the mixture was neutralized with saturated NaHCO3 solution, was extracted 3× with ethyl acetate, the combined organic phases were washed with saturated NaCl solution and were dried with MgSO4. After filtration 30 ml saturated KF solution were added, the mixture was filtered over Celite and evaporation-concentrated. Purification by chromatography on silica gel (dichloromethane/methanol 0-3%) yielded 120 mg 1-(5-fluoropyridine-2-yl)ethanone as an oil, which was directly reacted further.

1. temperaturethe mixture was heated 8 hours
2. temperatureat reflux
3. temperaturereflux
4. waitwas continued for an additional hour
5. extractionwas extracted 3× with ethyl acetate
6. washthe combined organic phases were washed with saturated NaCl solution
7. dry with materialwere dried with MgSO4
8. filtrationAfter filtration 30 ml saturated KF solution
9. additionwere added
10. filtrationthe mixture was filtered over Celite
11. concentrationevaporation-concentrated
12. customPurification by chromatography on silica gel (dichloromethane/methanol 0-3%)