Hydrochloric Acid → 4-(Difluoromethoxy)benzeneboronic acid

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Reaction Steps

A solution of (4-bromophenoxy)difluoromethane (3 g) and triisopropyl borate (3.42 ml) in tetrahydrofuran (15 ml) was cooled to −78° C. under argon atmosphere, and thereto was added a solution of n-butyl lithium (1.59 M hexane solution, 3.42 ml). The mixture was stirred at room temperature overnight. Added thereto was 6N aqueous hydrochloric acid at 0° C., and the mixture was extracted with ethyl acetate. The extract was washed with brine, and dried over magnesium sulfate. The solvent was evaporated under reduced pressure, and the residue was triturated with cold hexane to give 4-(difluoromethoxy)phenylboronic acid (1.88 g) as colorless solid.

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