反应详情

温度

85 °C

To 2-(5-bromo-2-fluorophenyl)-3,5-difluoropyridine (0.746 g, 2.59 mmol), and bis(neopentyl glycolato)diboron (0.704 9) was added dry 1,4-dioxane (9 mL) and dry dimethylsulfoxide (1.1 mL) followed by potassium acetate (0.542 g) and dichloro[1,1′-bis(diphenylphosphino)ferrocene]-palladium(II) dichloromethane adduct (0.080 g). The mixture was thoroughly degassed with nitrogen and then stirred at 85° C. for 24 h. On cooling to ambient temperature 1 N aqueous sodium hydroxide (24 mL) was added and the mixture stirred for 30 min. Diethyl ether was added and the aqueous phase separated and washed with diethyl ether. The organics were discarded. The aqueous phase was filtered then acidified to pH 5 by addition of 2 N aqueous hydrochloric acid (12 mL). The resulting solid was collected by filtration, washed with water and dried in vacuo at 60° C. to afford 4-fluoro-3-(3,5-difluoropyridin-2-yl)phenylboronic acid (0.618 g) as a colourless solid: δH (400 MHz, DMSO) 8.69 (1H, d, J 2), 8.21 (2H, s), 7.94-8.14 (3H, m), 7.34 (1H, dd, J 11 and 8).

1. customThe mixture was thoroughly degassed with nitrogen
2. temperatureOn cooling to ambient temperature 1 N aqueous sodium hydroxide (24 mL)
3. additionwas added
4. stirringthe mixture stirred for 30 min
5. additionDiethyl ether was added
6. customthe aqueous phase separated
7. washwashed with diethyl ether
8. filtrationThe aqueous phase was filtered
9. additionthen acidified to pH 5 by addition of 2 N aqueous hydrochloric acid (12 mL)
10. filtrationThe resulting solid was collected by filtration
11. washwashed with water
12. customdried in vacuo at 60° C.