Calcium Chloride → 2-Benzyl-3-(tert-butylsulfonyl)propanoic acid

Participants

Reaction Conditions

Reaction Steps

1.60 g (5.12 mmol) of ethyl (RS)-α-[(tert-butylsulfonyl)methyl]hydrocinnamate were treated with 50 ml of aqueous 5 mM calcium chloride solution and the reaction mixture was warmed to 38° C. while stirring. The pH value was adjusted to 7.5 with 1N sodium hydroxide solution. The hydrolysis was started by the addition of 150 mg of Savinase 6.0 T (NOVO, 2880 Bagsvaerd, Denmark). The pH value was held constant at 7.5 using automatic titration by dosing-in 1N sodium hydroxide solution while stirring vigorously at 38° C. After a consumption of 2.39 ml of 1N sodium hydroxide solution (after 21.3 hours), the reaction mixture was washed twice with 50 ml of ethyl acetate. The aqueous phase was acidified to pH 2.2 with 25% hydrochloric acid and extracted twice with 50 ml of ethyl acetate. The organic phase was dried over magnesium sulfate and evaporated at 1200 Pa/40° C., whereby there were obtained 690 mg (2.42 mmol, 47%, 94% of theory) of (S)-α-[(tert-butylsulfonyl)methylhydrocinnamic acid in the form of white crystals, which had an enantomeric excess of >99%. In order to determine the purity by gas chromatography, the compound obtained was silylated and likewise had a purity of >99%.

Provenance & Evidence