Water → 2-[2-(Difluoromethyl)phenyl]-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

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Reaction Conditions

Reaction Steps

To a solution of 1-bromo-2-difluoromethyl-benzene (19.8 g, 95.7 mmol) in dry THF (200 ml) at −78° C. under a nitrogen atmosphere was added 2.5 M n-BuLi in hexanes (42 ml, 105 mmol) slowly. After completion of the addition, the resulting dark solution was stirred for an additional hour at −78° C. Subsequently, 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (25 ml, 123 mmol) was added, and the solution was slowly warmed to room temperature. After stirring overnight at room temperature under a nitrogen atmosphere the solution was poured into 400 ml water. Ethyl acetate (300 ml) was added and the layers were separated. The aqueous layer was extracted twice with ethyl acetate (150 ml and 50 ml respectively), and the combined organic layers were washed with water, dried over Na2SO4, filtered, and evaporated to dryness under reduced pressure. The resulting brown oil (21 g) was purified by bulb-to-bulb-distillation at 3×10−3 mbar at 90-95° C. to yield 2-(2-difluoromethyl-phenyl)-4,4,5,5-tetramethyl-[1,3,2]dioxaborolane (14.4 g, 59%) as a slightly yellow oil.

Provenance & Evidence