ORGN 766 |
| Candida rugosa lipase (CRL)-catalyzed asymmetric esterification and transesterification of racemic 2-octanol with seven acyl donors were examined in organic solvents, reverse micelles and ionic liquid. The enantioselectivity of CRL varied widely with the change of reaction medium. CRL displayed much higher enantioselectivity in toluene in esterification reaction than in hexane and [BMIm][PF6] when octanoic acid was served as an acyl donor. However, toluene was not a good medium for esterification and transesterification of racemic 2-octanol with ethyl cyanoacetate, vinyl acetate, triethyl orthoformate, ethyl acetoacetate and succinic anhydride except with ethyl chloroacetate. Compared to AOT/isooctane/H2O and Triton X-100/butanol/octane/H2O reverse micelles, a high enantioselectivity of 2465.0 was observed in CTAB/butanol/isooctane/H2O reverse micelle. Furthermore, the e.e. of (S)-2-octanol obtained by employing the CTAB reverse micelle reached about 100%, which was higher than that observed in the most of lipase-mediated resolution of racemic 2-octanol, including in [BMIm][PF6] by CRL presented in this paper. It was suggested that CTAB reverse micelle is a more suitable medium than AOT, Triton X-100 system and [BMIm][PF6] for CRL-catalyzed asymmetric esterification or transesterification for resolution of racemic 2-octanol under stated conditions. |
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Asymmetric Reactions, Molecular Recognition, Self Assembly, Bioorganic Chemistry, Process R&D
8:00 PM-10:00 PM, Wednesday, 16 March 2005 Convention Center -- Hall D, Poster
Division of Organic Chemistry |