Hydrochloric Acid → (3,5-Difluorophenyl)boronic acid

Participants

Reaction Conditions

Reaction Steps

91.5 ml of tert-butyllithium are added at −78° C. to 20 g of 1-bromo-3,5-difluorobenzene in 300 ml of diethyl ether. The reaction mixture is stirred for 1 hour at −78° C. and 14.2 ml of trimethyl borate are then added. The reaction mixture is stirred for 1 hour at −78° C. and then for 12 hours at room temperature. 200 ml of aqueous 1 N hydrochloric acid solution are added. The resulting mixture is extracted with diethyl ether, the organic phase is washed with saturated sodium hydrogen carbonate solution and dried over magnesium sulphate, and the solvents are evaporated off under reduced pressure. The residue is taken up in cyclohexane and the precipitate obtained is isolated by filtration.

Provenance & Evidence