Hydrochloric Acid → (2,3-Difluorophenyl)boronic acid

Participants

Reaction Conditions

Reaction Steps

After 7.5 g of o-difluorobenzene was dissolved in 80 ml of dried tetrahydrofuran (THF), the solution thus formed was cooled down to -70° C. under a nitrogen atmosphere and then added dropwise with 42 ml of butyllithium (1.6 mol/liter hexane solution) at a temperature lower than -55° C. The solution was continuously stirred at the same temperature for 1.5 hours and added dropwise with a THF solution containing 24.8 g of triisopropylborate at a temperature of -65° C. to -60° C. After the dropping of the solution was finished, the solution was continuously stirred at an ambient temperature for 12 hours, added further with 60 ml of a 10% aqueous hydrochloric acid solution, and continuously stirred for 1 hour. The reaction mixture thus obtained was subjected to extraction with an ether, washed with water, dried, and subjected to distillation under a reduced pressure to separate the solvent to obtain 9.0 g of 2,3-difluorophenyl boronic acid.

Provenance & Evidence