Ammonium Chloride → 2-(3-(Cyclopropylmethoxy)-4-methoxyphenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

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Reaction Steps

To 60 ml of dehydrated tetrahydrofuran solution containing 3.64 g (14.2 mmol) of 4-bromo-2-cyclopropylmethoxy-1-methoxybenzene was added dropwise 18.0 ml of tetrahydrofuran solution containing 0.97M sec-butyl lithium at −70° C. under argon atmosphere, and the mixture was stirred at the same temperature for 50 minutes. Then, 3.70 ml (19.2 mmol) of 2-isopropoxy-4,4,5,5-tetramethyl-[1,3,2]-dioxaborolane was added to the mixture, and the resulting mixture was raised to room temperature. After completion of the reaction, a saturated aqueous solution of ammonium chloride was added to the reaction mixture, and after adjusting a pH thereof to 2 with 1N hydrochloric acid, the mixture was extracted with ethyl acetate. The organic layer after separation was washed with a saturated aqueous solution of sodium chloride, dried over anhydrous magnesium sulfate, and then, concentrated under reduced pressure to obtain 4.78 g (purity: 84.7%) of the title compound as a slightly yellowish oil. (Yield: 94%)

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