Hydrochloric Acid → HCID 10220047, compound

Participants

Reaction Conditions

Reaction Steps

At first, 5.5 g (40 mmol) of zinc chloride were added to a toluene solution (4 liters) containing 504 g (4.2 mol) of acetophenone (1a) as a ketone and 485 g (4.0 mol) of (S)-1-phenylethylamine ((S)-2a) as an optically active primary amine, followed by heating under reflux for 20 hr and by removing water (formed as a by-product) with a Dean-Stark tube during the reaction, in order to conduct the reaction. Then, 564 g (4.0 mol) of fluoral.ethylhemiacetal (4a) were dropped to the reaction liquid by spending 80 minutes at a temperature of not higher than 5° C., followed by stirring at 20° C. for 24 hr, thereby conducting the reaction. Then, 4-liter of 1N HCl were added to the reaction liquid, followed by stirring at room temperature for 1 hr, then washing with 2-liter of water, then concentration, and then vacuum drying, thereby obtaining 797 g of (R)-4,4,4-trifluoro-3-hydroxy-1-phenyl-1-butanone ((R)-5aa, purity: 71%). Its optical purity was found to be 59% ee by a chiral HPLC (DAICEL AS, n-hexane:i-propanol=95:5, 254 nm).

Provenance & Evidence