Nitrogen → (2-Fluoro-4-methylphenyl)boronic acid

Temperature

-70 °C

To a 500 mL three-necked round-bottomed flask equipped with septum and N2 inlet were added 10.0 g (52.9 mmol) 4-bromo-3-fluorotoluene and 100 mL dry tetrahydrofuran. The solution was cooled to −70° C., and 25.4 mL (63.5 mmol) of a 2.5 M solution of butyl lithium in hexane was added slowly so the temperature did not exceed −60° C. The clear solution was stirred at −70° C. for 1 hour, then treated with 10.8 mL (63.5 mmol) triethylborate. The reaction was stirred for 2 hours at −70° C., then warmed to room temperature and stirred for 16 hours. The reaction was quenched with saturated aqueous ammonium chloride solution, adjusted to pH 1-2 with 1 N hydrochloric acid, and extracted with ethyl acetate. The organic layer was washed with brine, dried over sodium sulfate, and evaporated. The residue was triturated with hexane to a white solid, 6.1 g (75%), as a mixture of monoaryl and diaryl boronic acids.

1. customdid not exceed −60° C
2. stirringThe reaction was stirred for 2 hours at −70° C.
3. temperaturewarmed to room temperature
4. stirringstirred for 16 hours
5. customThe reaction was quenched with saturated aqueous ammonium chloride solution
6. extractionextracted with ethyl acetate
7. washThe organic layer was washed with brine
8. dry with materialdried over sodium sulfate
9. customevaporated
10. customThe residue was triturated with hexane to a white solid, 6.1 g (75%), as a mixture of monoaryl and diaryl boronic acids

ORD record

ord-3ce36dad2f7e49b88f501e441afa7a2a

Source dataset

uspto-grants-2002_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06362195B1