Hydrogen Bromide → (R)-1-bromo-1-[3,5-bis(trifluoromethyl)phenyl]ethane

Temperatur

20.5 °C

Under an argon atmosphere, (S)-1-[3,5-bis(trifluoromethyl)phenyl]ethanol (1.0 g, 3.87 mmol, >99.5% ee) was added dropwise with phosphorus tribromide (0.52 g, 1.94 mmol) on a water bath at a temperature lower than 20° C., and the mixture was stirred at 19 to 22° C. for 30 minutes. The reaction mixture was cooled, and added dropwise with hydrogen bromide (30% solution in acetic acid, 0.76 mL, 3.87 mmol) at a temperature lower than 0° C., and the mixture was stirred at 13 to 15° C. for 18 hours. The reaction mixture was poured into ice water, and the mixture was extracted with n-hexane (15 mL×2). The organic layers were combined, washed with saturated aqueous sodium hydrogencarbonate (15 mL×1) and then with saturated brine (15 mL×1), dried over anhydrous sodium sulfate, and then concentrated under reduced pressure. The resulting crude product was purified by column chromatography (silica gel, 8 g; developing solvent, n-hexane) to obtain 1.06 g of (R)-1-bromo-1-[3,5-bis(trifluoromethyl)phenyl]ethane as colorless oil.

1. temperatureThe reaction mixture was cooled
2. stirringthe mixture was stirred at 13 to 15° C. for 18 hours
3. extractionthe mixture was extracted with n-hexane (15 mL×2)
4. washwashed with saturated aqueous sodium hydrogencarbonate (15 mL×1)
5. dry with materialwith saturated brine (15 mL×1), dried over anhydrous sodium sulfate
6. concentrationconcentrated under reduced pressure
7. customThe resulting crude product was purified by column chromatography (silica gel, 8 g; developing solvent, n-hexane)

ORD-Eintrag

ord-5081f08da31041fcb9c28380229358dc

Quelldatensatz

uspto-grants-2016_03

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US09272966B2