4-(Naphthalen-2-yl)phenylboronic acid

22082-99-1

918655-03-5

Under argon protection, 50.0 g (177 mmol) of 4-(2-naphthalene)bromobenzene was mixed with 500 mL of anhydrous tetrahydrofuran (THF) and cooled to -60 °C. Subsequently, 136 mL (212 mmol) of a hexane solution of 1.56 M n-butyllithium was pre-cooled to -60 °C and slowly added dropwise to the reaction mixture under stirring. After the dropwise addition was completed, the reaction mixture continued to be stirred at -60 °C for 1 hour. Next, 99.6 g (529 mmol) of triisopropyl borate was slowly added dropwise at the same temperature. After completion of the dropwise addition, the reaction mixture was gradually warmed to room temperature and stirred continuously for 18 hours. After completion of the reaction, aqueous hydrochloric acid was added to the mixture and stirred for 1 hour at room temperature. After that, toluene was added for extraction and the aqueous phase was separated and discarded. The organic phase was dried with magnesium sulfate and concentrated under reduced pressure to remove the solvent. Finally, the resulting solid was purified by recrystallization from toluene to give 33.6 g of (4-(naphthalen-2-yl)phenyl)boronic acid in 84% yield.