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Enancjoselektywna enzymatyczna desymetryzacja katalizowana lipazami. Część II, Optymalizacja warunków reakcji. Związki mezo

Karczmarska-Wódzka A., Kołodziejska R., Tafelska-Kaczmarek A., Przybyła T., Dramiński M.

Wiadomości Chemiczne

2013

[Z] 67, 9-10

819--841

In the enzymatic asymmetric synthesis, the enzyme allows the desymmetrization of achiral compounds resulting in chiral compounds of high optical purity. Meso compounds (bearing a plane of symmetry) are very important group of compounds used in EEDs (Scheme 1) [1–4]. Similarly to prochiral compounds, selective acylation or hydrolysis of meso substrates leads to optically active products. Most lipases preferentially convert the same enantiomers in the above mentioned types of reaction. This allows the preparation of the both enantiomers of the product in high chemical and optical yield (Scheme 3–20) [35–58]. An effective enzymatic catalysis should be performed under conditions optimal for a biocatalyst performance. Hence, it is essential to select an appropriate reaction medium, the pH, and temperature [6–34]. Optimization of the reaction conditions in terms of an appropriate solvent selection is effective and most frequently the simplest way to modify the enzyme selectivity. One of the most important criteria for the solvent selection is its nature [25]. The enzyme selectivity is conditioned by its conformational rigidity, which increases in more hydrophobic medium (typical hydrophobic solvents, scCO2). A hydrophobic solvent decreases biocatalyst lability, which does not allow the connection between the structurally mismatched substrate and the active side of an enzyme [10, 26–31]. Ionic liquids are a separate group of solvents which, despite their high hydrophobicity (logP << 0) and polarity, can constitute an ideal medium for the biotransformation reactions [18–23].