1-Bromo-2-Chloroethane → 1-(2-chloroethyl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole

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Reaction Conditions

Reaction Steps

A mixture of 4-(4,4,5,5-Tetramethyl-[1,3,2]dioxaborolan-2-yl)-1H-pyrazole (560 mg, 2.89 mmol), 1-Bromo-2-chloro-ethane (0.36 mL, 4.39 mmol), and cesium carbonate (2.81 g, 8.67 mmol) in acetonitrile (20 mL) stirred at 62° C. for 4 hrs. The mixture was cooled, diluted with water and extracted with ethyl acetate. The organics were washed with water and brine, dried over anhydrous sodium sulfate, filtered and concentrated to afford the title compound (664 mg, 90%). 1H NMR (300 MHz, CDCl3): δ 7.84 (s, 1H), 7.79 (s, 1H), 4.45 (t, 2H), 3.90 (t, 2H), 1.34 (s, 12H).

Provenance & Evidence