Tributyl borate → 2-Fluoropyridine-4-boronic acid

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of n-butyl lithium (3.2 mL 2.5M, 8.0 mmol) in dry diethyl ether (20 mL) at −78° C. was added a solution of 2-fluoro-4-iodopyridine (1.5 g, 6.7 mmol) in dry ether (10 mL) and the reaction mixture was stirred at −78° C. for 10 minutes. Tributyl borate (2.4 mL, 2.01 g, 8.7 mmol) was added and the reaction mixture was allowed to stir to room temperature over 2 hours. Water (5 mL) was added followed by 2N aqueous sodium hydroxide solution (10 mL) to sissolve the solids. The organic phase was separated. The aqueous phase was acidified to pH3 using 6N HCl and the resulting white solid was collected by filtration and dried under vacuum to give the title compound, 0.74 g (78%). 1H NMR (DMSO-d6) δ 8.65 (br s, 2H), 8.21 (d, 11H, J=4.8 Hz), 7.59 (t, 1H, J=4.8 Hz), 7.37 (d, 1H, J=1.8 Hz).

Provenance & Evidence