Sulfuric Acid → 3-Cyanophenylboronic acid

Participants

Reaction Conditions

Reaction Steps

20 g of 3-bromobenzonitrile was dissolved in 100 ml of dry THF and, under a nitrogen atmosphere, 37.6 ml of triisopropoxyborane was added. This solution was cooled to −78° C., and 98.3 ml of 1.6M n-butyllithium hexane solution was dropped for 30 min. with stirring. After stirring at room temperature for 30 min., it was cooled to 0° C., 220 ml of 4M sulfuric acid was added. This solution was refluxed with heating overnight, and then cooled to 0° C. again. 340 ml of 5M sodium hydroxide was added, and extracted with 200 ml of diethyl ether. The aqueous layer was removed, and 6M hydrochloric acid was added until the pH was 2. It was extracted twice with 300 ml of ethyl acetate, dried with magnesium sulfate, and then the solvent was removed. The resulting crude product was recrystallized from DMF-water to produce 11.6 g (72%) of the title compound as acicular light-yellow crystals.

Provenance & Evidence