Diisopropyl Ether → (R)-2-bromo-1-(3-chlorophenyl)ethanol

Participants

Reaction Steps

To 100 mg (0.4 mmol) of 2-bromo-1-(3-chlorophenyl)ethanol were added 30 mg of Lipase QL (available from Meito Sangyo Co., Ltd.) and 40 mg (0.4 mmol) of acetic anhydride. Diisopropyl ether was added to the mixture to make the total volume to 1 ml. The reaction mixture was then allowed to undergo reaction at a temperature of 35° C. for 72 hours. After the termination of the reaction, the enzyme was removed by filtration. The resulting filtrate was then concentrated under reduced pressure. The concentrated solution was analyzed by 1H-NMR. As a result, it was found that (R)-2-bromo-1-(3-chlorophenyl) ethanol and (S)-2-bromo-1-(3-chlorophenyl)ethyl acetate had been produced in a proportion of 2:3. The concentrated solution was then separated by a thin layer silica gel chromatography. As a result, (R)-2-bromo-1-(3-chlorophenyl)ethanol ([α]D20 =-25.6°, C=1.05) and (S)-2-bromo-1-(3-chlorophenyl)ethyl acetate ([α]D20 =+40.4°, C=0.60) were obtained. The optical purity of (R)-2-bromo-1-(3-chlorophenyl)ethanol thus obtained was analyzed by Chiral HPLC. The results were 100% ee.

Provenance & Evidence