Two Approaches for CAL-B-Catalyzed Enantioselective Deacylation of a Set of α-Phenyl Ethyl Esters: Organic Solvent with Sodium Carbonate and Micro-aqueous Medium

Abstract

Herein, we report an efficient enantioselective cleavage of the acyl-moiety of a set of α-phenyl ethyl esters with different chain-lengths catalyzed by lipase B from Candida antarctica (CAL-B) by comparing two reactional approaches: anhydrous media with sodium carbonates and micro-aqueous medium. The deacylation is performed in organic solvent, in the presence of Na2CO3 in the first case, and by addition of a drop of phosphate buffer solution pH=7 in the second. The results show the high efficiency of the deacylation in the presence of the sodium carbonate for the enzymatic resolution of all the esters and that in term of reactivity (31% ≤ conv ≤ 50%) and selectivity (E >200). While, during the hydrolysis in micro-aqueous media, the conversion is strongly affected by the length of the acyl-chain side, the conversion decreases from conv =50% with the 1-phenylethyl acetate 1a to conv =19% with 1-phenyethyl dodecanoate 6a, and this, even if the selectivity remains high (E>89). In both conditions, the lipase CAL-B shows a high enantioselectivities in favor of (R)-1-phenyl ethanol enantiomer (conv >45%, E>200) but the reactivity is modulated by the form and the size of the acyl-chain side.

Valorization of Chicken Viscera as Natural Raw Material Source: Application to Hydrolysis of Fatty Esters for Sewage Treatment

“…In the continuity of our laboratory investigations on the use of kinetic resolution reactions catalyzed by lipases to access to enantiomerically enriched building blocks, for example the fatty esters trough esteri cation and hydrolysis [34][35][36], we have scrutinized the enzymatic reactivity and selectivity of this newly developed biocatalyst.The kinetic resolution of sec-1-phenylethanol by acylation with succinic anhydride and by hydrolysis of the corresponding ester were selected [37][38][39].…”