Kinetic resolution of 2-substituted 3-hydroxy esters was examined by lipase PS catalyzed transesterification using vinyl acetate as an acyl donor. Resolution of (Β±)-syn-and -anti-1a, -1e possessing a small methyl group at the C-3 position was accomplished enantioselectively. The outcome of the resol
Lipase-catalyzed enantioselective transesterification toward esters of 2-bromo-tolylacetic acids
β Scribed by David Guieysse; Christophe Salagnad; Pierre Monsan; Magali Remaud-Simeon
- Publisher
- Elsevier Science
- Year
- 2003
- Tongue
- English
- Weight
- 188 KB
- Volume
- 14
- Category
- Article
- ISSN
- 0957-4166
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β¦ Synopsis
Lipases from Candida antarctica, Pseudomonas cepacia and Rhizomucor miehei were tested in the resolution of seven racemic substrates belonging to the (RS)-2-bromo tolyl acetate ester category, but differing either in the position of the methyl substituent on the acyl part of the aromatic ring, or in the structure of the alkyl group. Lipase-catalyzed kinetic resolution via transesterification reaction between the ester and octanol in octane revealed that, of the three enzymes tested, P. cepacia lipase is the most efficient for resolution of the various racemates, with R-enantiopreference. In addition, the position of the methyl substituent was found to play a key role in governing the enantioselectivity of the reaction. Using P. cepacia lipase and 2-bromo-m/p-tolyl-or 2-bromophenylacetic acid esters E-values of >50 were measured, whereas with the ortho derivatives, E-values dramatically decreased to <6.
π SIMILAR VOLUMES
The lipase-catalyzed irreversible transesterification procedure using vinyl esters was applied to the resolution of racemic 2-phenoxypropanoic acids. Aspergillus niger lipase showed high enantioselectivities and reasonable reaction rates. The enantioselectivity was found to be affected profoundly by
## Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a βFull Textβ option. The original article is trackable v
Highly enantioselective hydrolyses of syn-3-acetoxy-2-methyl ester and anti-3-acetox.y-Z-methyl esters with lipase "Amano A" and lioase "Amano A-6" isolated from Aspergillus-niger, are described. In the synthetic studies of erythronolide A, it was required to prepare (2R,3R)-2,4-dimethyl-3-hydroxy-4