Hydrochloric Acid → 4-(Difluoromethoxy)benzeneboronic acid

Participants

Reaction Steps

To a stirred solution of 1-bromo-4-(difluoromethoxy)-benzene (1.18 g) and triisopropyl borate (1.34 ml) in tetra-hydrofuran (6 ml) was added dropwise n-butyl lithium (1.58 M hexane solution, 3.68 ml) at −78° C. over 10 minutes under argon atmosphere, then the reaction mixture was allowed to warm to room temperature. After being starred at room temperature for 3 hours, the mixture was cooled to 0° C., and thereto were added a 6 N aqueous hydrochloric acid solution and water. The resultant mixture was extracted with ethyl acetate (30 ml) twice, and the combined organic layer was washed with brine (10 ml), dried over sodium sulfate. The insoluble materials were filtered off, and the filtrate was evaporated under reduced pressure. The residual solid was triturated with cold hexane to give the titled compound as a colorless solid. 1H-NMR (DMSO-d6) δ 7.12 (d, J=8.4 Hz, 2H), 7.27 (t, J=74.1 Hz, 1H), 7.83 (d, J=8.6 Hz, 2H), 8.08 (br-s, 2H).

Provenance & Evidence