Hydrochloric Acid → 4-Chloro-3-(difluoromethoxy)phenylboronic acid

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Reaction Steps

2 M hydrochloric acid (10 mL) was added to the crude product of 2-(4-chloro-3-difluoromethoxyphenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (1.14 g) in tetrahydrofuran (10 mL), and the mixture was stirred at room temperature for four hours. Water and ethyl acetate were added to the reaction solution, followed by extraction with ethyl acetate. The organic layer was extracted with a 2 M sodium hydroxide solution. The resulting solution was made acidic with concentrated hydrochloric acid and then extracted with ethyl acetate. The organic layer was dried over anhydrous magnesium sulfate and filtered. The filtrate was concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography (hexane:ethyl acetate=99:1→50:50) to give the title compound (93 mg).

Provenance & Evidence