1,4-Dioxane → 4-Fluoro-3-(pyridin-2-yl)phenylboronic acid

Participants

Reaction Conditions

Reaction Steps

To 2-(5-bromo-2-fluorophenyl)pyridine (544 mg, 2.16 mmol) and bis(neopentyl glycolato)diborane (585 mg, 2.60 mmol) under nitrogen was added dry potassium acetate (450 mg, 4.58 mmol), anhydrous 1,4-dioxane (8 ml) and DMSO (1 ml). The mixture was degassed with nitrogen, and [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II) complex with dichloromethane (50 mg, 3 mol %) was added. After stirring at 85° C. under nitrogen for 15 h, the mixture was cooled to room temperature, and sodium hydroxide solution (20 ml of a 1 M solution) was added. The mixture was stirred for 10 min, and was then extracted twice with diethyl ether. The combined ether extractions were washed with water, then the combined aqueous layers were filtered through a glass fibre filter paper. The pH of the filtrate was adjusted to 6 by the addition of 2 N hydrochloric acid, precipitating a white solid. This was collected by filtration, washed with water and dried in vacuo at 60° C., and was found to be 4-fluoro-3-(pyridin-2-yl)phenylboronic acid (455 mg, 97%): 1H NMR (400 MHz, DMSO) δ 7.30 (1H, dd, J 8.2, 11.7 Hz), 7.41 (1H, m), 7.77 (1H, m), 7.90 (2H, m), 8.16 (2H, s), 8.36 (1H, dd, J 1.6, 8.6 Hz), 8.72 (1H, m).

Provenance & Evidence