Subtilisin-Carlsberg-catalyzed hydrolysi

Scheme 5.24 Subtilisin-Carlsberg-catalyzed hydrolysis of sulfinamides.

Early reports on the effects of the choice of solvent on enzymatic enantioselectivity showed that substantial changes may be observed. For the transesterification reaction of sec-phenethyl alcohol with vinyl butyrate catalyzed by subtilisin Carlsberg, a 20-fold increase in the E-value was reported when the medium was changed from acetonitrile to dioxane [59]. Similar changes were recorded for the prochiral selectivity of Pseudomonas sp. lipase in the hydrolysis of 2-substituted... 

A similar resolution has also been achieved on large scale <20040PD22>. The KR of racemic isoxazoline 312 catalyzed by enzymes was studied. The best result was obtained with lipase B from Candida antarctica (CALB), which hydrolyzed the ethyl ester of (—)-312 to the corresponding monoacid (—)-313. The reaction, which was run in 0.1 M phosphate buffer/acetone at room temperature, spontaneously stopped at 50% conversion to yield monoacid (—)-313 and the residual ester (- -)-312 with ees higher than 99% <2004TA3079>. The C-5 epimer of 312 underwent enantioselective hydrolysis (>99% ee) of the methyl ester linked to C-5 in the presence of the protease proleather (subtilisin Carlsberg), whereas CALB and other lipases were not able to resolve it (Equation 53). 

---