Triisopropyl borate → 5-Fluoro-2-(methylthio)phenylboronic acid

Temperature

-78 °C

The (2-bromo-4-fluorophenyl)(methyl)sulfane (700 mg, 3.17 mmol) was dissolved in THF (5 mL) and cooled to −78° C. To the cooled solution was added n-BuLi (2.18 mL, 3.48 mmol) dropwise. The reaction was stirred for 2 min at −78° C. then the triisopropyl borate (0.804 mL, 3.48 mmol) was added dropwise and the reaction mixture was allowed to warm to 0° C. over a period of approximately 90 min. The reaction was quenched by addition of 1N HCl solution and was stirred for 5 min. The mixture was then extracted with EtOAc (2×50 mL). The combined organic layers were washed with water (1×30 mL), brine (1×30 mL) and dried over magnesium sulfate. The crude product was then triturated with hexanes. The resulting solid was purified by medium pressure chromatography (silica gel, 0 to 50% EtOAc:hexanes) to give 5-fluoro-2-(methylthio)phenylboronic acid. Mass Spectrum (ESI) m/e=187.0 (M+1).

1. temperatureto warm to 0° C. over a period of approximately 90 min
2. customThe reaction was quenched by addition of 1N HCl solution
3. stirringwas stirred for 5 min
4. extractionThe mixture was then extracted with EtOAc (2×50 mL)
5. washThe combined organic layers were washed with water (1×30 mL), brine (1×30 mL)
6. dry with materialdried over magnesium sulfate
7. customThe crude product was then triturated with hexanes
8. customThe resulting solid was purified by medium pressure chromatography (silica gel, 0 to 50% EtOAc:hexanes)

ORD record

ord-b154f52eccd3416fbd55192b5ec42bde

Source dataset

uspto-grants-2015_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08940724B2