Scoping the Enantioselective Desymmetrization of a Poorly Water-Soluble Diester by Recombinant Pig Liver Esterase

Previously, the biocatalytic desymmetrization of dimethyl cyclohex-4-ene-cis-1,2-dicarboxylate to (1S,2R)-1-(methoxycarbonyl)cyclohex-4-ene-2-carboxylic acid, an important intermediate toward the synthesis of biologically active molecules, had been well-characterized in terms of pH and temperature optima and several aspects of process performance. Eventually this promising reaction could convert 200 mM (40 g·L–1) of substrate with >99.5% ee using the recombinant pig liver esterase, ECS-PLE06, at a scale of 8.8 L. However, the precise influence of substrate concentration and the poorly water-soluble nature of the substrate (approximately 60 mM in water at 25 °C for structurally similar dimethyl 1,4-cyclohexanedicarboxylate) remained elusive. Therefore, this work focuses on using a recently published methodology based on reaction trajectory analysis to identify mass transfer limitations in this reaction. With the constraints of mass transfer on space-time yield considered, it was possible to evaluate and im...