Improved racemate resolution of pentan-2-ol and trans-Z-cyclooct-5-ene-1,2-diol by lipase catalysisReportar como inadecuado

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1 LIENSs - LIttoral ENvironnement et Sociétés - UMR 7266

Abstract : Lipases are important catalysts in chiral synthesis due to their wide substrate recognition combined witha high stereoselectivity. We demonstrate here that the state, free or immobilized, of Candida antarcticalipase B CaLB affects enantioselectivity and also alters the temperature dependancy of the enzyme. Thisindicates that CaLB undergoes various conformations induced by its interaction with the different immo-bilization supports studied. Molecular imprinting experiments, using immobilized enzyme co-dried withmimic substrate molecules, enhanced the enantiomeric ratio two-fold or three-fold, depending on theimmobilization support. The structure of the acyl donor has a pronounced effect on CaLB catalyzed res-olution, due to the proximity of the acyl and alcohol moieties during catalysis. When the acylation ofpentan-2-ol was examined, we found that the 3C methyl propanoate donor afforded the highest resolu-tion. Trans-Z-cyclooct-5-en-1,2-diol was used as a model racemic substrate to study the ability of lipaseto catalyze the resolution of difunctionalized compounds. There was a clear enhancement in the enan-tiomer selectivity of the biotransformation of the diol when vinyl butanoate is used as the acyl donor. Theconversion and enantiomeric excess of 1R,2R-monoacetates were enhanced, using immobilized CaLB,when the chain length of the donors increased from C2 to C4.

Autor: Marianne Graber - Hervé Rouillard - Régis Delatouche - Najla Fniter - Belsem Belkhiria - Antoine Bonnet - Lisiane Domon - Valé



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