2-(Dimethylphenylsilyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

A Representative procedure for the boryl substitution reaction of aryl halide:
To a vial sealed with a screw cap containing a silicon-coated rubber septum is added potassium methoxide (0.6 mmol) under argon. It is connected to a vacuum/nitrogen manifold through a needle. DME (5 mL) and 1 (0.36 mmol) are added to the vial, then stirred for 10 min at 30 °C. 4-Bromoanisole (0.50 mmol) is added dropwise and stirred for 1 h. The solution is cooled to 0 °C followed by the addition of TBAF (1.0 M, 800 µL). The resultant solution is stirred for 3 h at 0 °C. After that, the mixture is added to the H₂O (100 mL), then extracted with Et₂O (50 mL). The organic layer is washed with water (50 mL x 2). The combined organic layer is then dried over MgSO₄ followed by evaporation. The crude product is purified by boric acid-impregnated silica-gel column chromatography with 0–5% hexane/Et₂O eluent to give the desired product (77% isolated yield) as a colorless oil.