Biphenyl-3-boronic acid

• Coupling with potassium cyanate, quinones, or fluorous tagged N-hydroxyphthalimide
• Direct C-H arylation of electron-deficient heterocycles

2113-57-7

5122-95-2

The general procedure for the synthesis of 3-biphenylboronic acid from 3-bromobiphenyl was as follows: 3.8 g (16 mmol) of 3-bromobiphenyl was added to a 300 mL three-neck flask under nitrogen protection. 100 mL of tetrahydrofuran (THF) was added to dissolve, and the solution was subsequently cooled to -80 °C. Under stirring, 11 mL (18 mmol) of n-butyllithium (1.6 mol/L hexane solution) was slowly added dropwise via syringe. After the dropwise addition was completed, the reaction was kept at -80 °C with continued stirring for 1 hour. Subsequently, 2.2 mL (20 mmol) of trimethyl borate was added to the reaction system and the reaction mixture was allowed to gradually warm up to room temperature with continued stirring for 4 hours. Upon completion of the reaction, the reaction was quenched by the addition of about 50 mL of dilute hydrochloric acid (1.0 mol/L) and stirring was continued for 2 hours. The reaction mixture was transferred to a partition funnel and the aqueous layer was extracted with ethyl acetate. The organic layers were combined and washed sequentially with saturated sodium bicarbonate solution and saturated saline. The organic layer was dried with anhydrous magnesium sulfate and filtered to remove the desiccant. The filtrate was concentrated under reduced pressure to give an oil. Hexane was added to the oily material and a white solid was precipitated. The solid was collected by filtration and dried to give 1.7 g of white powdery 3-biphenylboronic acid in 55% yield.