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

Participants

Reaction Conditions

Reaction Steps

In a nitrogen atmosphere, a solution prepared by dissolving 100 g of 3,5-difluorobromobenzene in 150 mL of THF was added dropwise at a rate that caused gentle reflux to a mixed solution of 13.85 g of magnesium and 55 mL of THF. After dropwise addition, the mixture was stirred at 40° C. for 1 hour and cooled with ice. Then, a solution prepared by dissolving 64.59 g of trimethoxyborane in 130 mL of THF was slowly added dropwise under ice cooling, followed by stirring at room temperature for 1 hour. Then, 10% hydrochloric acid was added until the reaction system became acidic, and the mixture was stirred at room temperature for 30 minutes. Then, an organic layer was separated from the mixture, and an aqueous layer was subjected to extraction with hexane. The hexane extract was combined with the organic layer and washed with saturated brine. The resultant mixture was dried by adding sodium sulfate, and then the solvent was distilled off under reduced pressure to yield 71.65 g of 3,5-difluorophenylboronic acid.

Provenance & Evidence