269409-97-4

95-55-6

73183-34-3

269409-97-4

GENERAL PROCEDURE: To a solution of o-aminophenol (0.5 mmol, 1.0 eq.) in methanol (1.0 mL) was added hydrochloric acid (0.5 mL, 1.5 mmol, 3.0 eq.) followed by water (0.5 mL). The mixture was stirred for 2 minutes and then sodium nitrite solution (0.25 mL) was added. Sodium nitrite solution was prepared by dissolving 35 mg of sodium nitrite in water (0.25 mL). The mixture was stirred at 0-5°C for 30 minutes, followed by the addition of a methanol (1.0 mL) solution of pinacol ester of bisboronic acid (2,381 mg, 1.5 mmol, 3.0 equiv). The reaction mixture was stirred for 60 minutes. Upon completion of the reaction, it was diluted with water (10 mL) and then extracted with dichloromethane (50 mL, 3 times). The organic layers were combined, washed with saturated sodium bicarbonate solution, dried over anhydrous sodium sulfate, concentrated and the crude product was purified by fast chromatography to give 2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenol.