Sulfuric Acid → 3-Cyanophenylboronic acid

Participants

Reaction Conditions

Reaction Steps

20 g of 3-bromobenzonitrile was dissolved in 100 ml of dry THF, and then mixed with 37.6 ml of triisopropoxyborane in the atmosphere of nitrogen. The solution was cooled at −78° C., and then 98.3 ml of a 1.6M n-butyl lithium hexane solution was dropwisely added to the cooled solution for about 30 minutes with stirring. The mixture was stirred at room temperature for 30 minutes, cooled at 0° C. and mixed with 220 ml of 4M sulfuric acid. The solution was heated and refluxed overnight, again cooled at 0° C., mixed with 340 ml of a 5M aqueous solution of sodium hydroxide, and then extracted with 200 ml of diethyl ether. The aqueous phase was separated, mixed with 6M hydrochloric acid until to give pH 2, and then twice extracted with 300 ml of ethyl acetate. The obtained ethyl acetate layer was dried over MgSO4, and the solvent was distilled away. The obtained crude product was recrystallized from DMF-water to obtain 11.6 g (72%) of the title compound as needle-like pale yellow crystals.

Provenance & Evidence