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

Participants

Reaction Steps

Under an argon atmosphere, 1,2-dibromo-1,1,2,2-tetrachloroethane (7.57 g, 23.2 mmol) was dissolved in toluene (12.5 mL), the solution was added with triphenylphosphine (6.1 g, 23.2 mmol) at 0° C., and the mixture was stirred for 30 minutes. This reaction mixture was added dropwise with a solution of (S)-1-[3,5-bis(trifluoromethyl)phenyl]ethanol (1) (5.0 g, 19.4 mmol, >99.5% ee) in toluene (12.5 mL) at 0° C. over 10 minutes or more, and then the mixture was warmed to room temperature, and stirred for 1 hour at the same temperature. The reaction mixture was added with n-hexane (25 mL), and the mixture was filtered through Celite. The filtrate was successively washed with water, saturated aqueous sodium hydrogencarbonate, and saturated brine, dried over sodium sulfate, and then evaporated under reduced pressure. The resulting residue was distilled under reduced pressure (56° C., 0.7 mmHg) to obtain 5.52 g of (R)-1-bromo-1-[3,5-bis(trifluoromethyl)phenyl]ethane (2) as colorless oil (yield: 88.6%).

Provenance & Evidence