Synthesis
Triphenylphosphine (2.75 g, 10.5 mmol) and carbon tetrabromide (3.48 g, 10.5 mmol) were added to a dry reaction flask followed by the addition of 25 mL of ether and the resulting mixture was stirred at room temperature for 30 min, then an ether solution of 3,5-difluorobenzenemethanol (10.5 mmol) was slowly added to the above mentioned system and the reaction mixture was continued to be stirred at 25C for 40 minutes. At the end of the reaction, petroleum ether was added to the reaction system, and a white precipitate of triphenylphosphine oxide was observed. Most of the triphenylphosphine oxide was removed by filtration, and the obtained filtrate was concentrated in vacuum, and finally, hexane was used as the eluent, and the residue was separated and purified by silica gel chromatography to obtain the target product of 3,5-difluorobenzyl bromide.
