Lipase-catalyzed kinetic resolution of (RS)-hydroxy tellurides

Santos, Alcindo A. Dos; Costa, Carlos Eduardo da; Princival, Jefferson L.; Comasseto, J. V.

doi:10.1016/j.tetasy.2006.07.024

Cited by 27 publications

(5 citation statements)

References 20 publications

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“…[5][6][7] Lipases can catalyze the resolution of several racemic compounds including alcohols, 8 amines, 9 acids, 10 a-hydroxy selenides 11 and tellurides. 12 Due to the poor solubility in water of most of these compounds, the enzymatic resolution is usually performed in non-aqueous media, but enzymes can denature in such media. A practical technique to improve the enzyme efficiency, operational stability and performance in organic solvents is the use of biocatalyst immobilization.…”

Section: Introductionmentioning

confidence: 99%

Enantioselective resolution of (R,S)-1-phenylethanol catalyzed by lipases immobilized in starch films

Hoffmann¹,

Silva²,

Nascimento³

2011

J. Braz. Chem. Soc.

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Lipases de diferentes fontes e dois micélios, na forma livre ou imobilizados em filme de amido de gengibre, foram utilizados como catalisadores na reação do (R,S)-1-feniletanol (1) com acetato de vinila e outros agentes acilantes. Os efeitos de vários parâmetros na resolução de (1) catalisada pela lipase de Burkholderia cepacia (LBC) imobilizada em filme de amido de gengibre (tipo do doador acila, razão molar álcool:doador acila, temperatura e solvente orgânico) foram avaliados. A eficiência catalítica da LBC imobilizada em blendas de amido de gengibre e poli (oxido de etileno) (PEO), em diferentes composições, também foi estudada. Os acetato de vinila e o de iso-propenila forneceram as maiores conversões (9%) e excessos enantioméricos em (R)-éster (> 99%). A razão molar álcool:doador acila e temperatura ótima foram de 1:1 e 28 °C, respectivamente. A mistura de n-hexano/glicerol (9:1 v:v) foi a mais adequada para esta reação (conversão 23%, E > 200). A blenda de amido de gengibre/PEO (7:3 m/m) foi reutilizada por seis vezes consecutivas.Lipases from different sources and two mycelium-bound lipases, in a free or immobilized form, in ginger starch film were screened as biocatalysts in the reaction of (R,S)-1-phenylethanol (1) with vinyl acetate and other acylating agents. The effect of various reaction parameters in the resolution of (1) catalyzed by lipase from Burkholderia cepacia (BCL) immobilized in ginger starch film was evaluated (acyl donor type, alcohol:acyl donor molar ratio, temperature and organic solvent). The catalytic efficiency of BCL immobilized in polymeric blends of ginger starch and polyethylene oxide (PEO), in different compositions, was also studied. Vinyl acetate and iso-propenyl acetate furnished the highest conversion (9%) and enantiomeric excess (> 99%) of the (R)-ester. The alcohol:acyl donor molar ratio and temperature optimum were 1:1 and 28 °C, respectively. The mixture of n-hexane/glycerol (9:1 v:v) was the most adequate for this reaction (conversion 23%, E > 200). The ginger starch/PEO (7:3 m/m) blend was successfully reused six times consecutively. Keywords: starch film, immobilization, lipases, enzymatic resolution IntroductionIn recent years, the application of enzymes and microorganisms as biocatalysts in organic synthesis has become a well-known technique.1,2 Enzymatic procedures to obtain a wide range of products under mild and environmentaly-friendly conditions have become attractive and promising due to the excellent stereoselectivity of enzymes.3 Lipases (triacylglycerol hydrolases EC 3.1.1.3) are the most widely applied enzymes for regio-, chemoand enantioselective biotransformations, because they also possess wide substrate specificity, have an excellent ability to recognize chirality, and do not require cofactors.1,4 They have found wide usage in a growing range of industrial applications, such as in detergents, food processing, biotransformations, waste treatment and bioremediation. They have been used by the pharmaceutical, cosmetics, textile, leather and paper industri...

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Section: Introductionmentioning

confidence: 99%

Enantioselective resolution of (R,S)-1-phenylethanol catalyzed by lipases immobilized in starch films

Hoffmann¹,

Silva²,

Nascimento³

2011

J. Braz. Chem. Soc.

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“…In view of this fact, we undertook a systematic investigation on their reactivity and found that b-telluroketones can be converted to the corresponding ketals [16,17] and telluroaldehydes, ketones and esters can be reduced to corresponding hydroxytellurides [18], which were resolved into enantiomers by enzymatic kinetic resolution [19]. All these tellurium containing compounds can be transformed into reactive organometallics, by Te/Li exchange [20], followed by transmetallation [18,21].…”

Section: Resultsmentioning

confidence: 99%

Hydrochalcogenation of activated olefines. Synthesis of functionalized dialkylchalcogenides

Comasseto

Gariani

Princival

et al. 2008

Journal of Organometallic Chemistry

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“…The enantioenriched isomers of the alcohol 5 were submitted to treatment with butyllithium and the (S)-dianion 7 was reacted with carbon dioxide leading to γ -Valerolactone (14). 13 Additionally, it was studied the conversion of dianions 7 and 8 into dicerium entities aiming the preparation of some spiroketals. Initially, the generated dianion (7 or 8) was added to a suspension of cerium trichloride in THF at low temperature and the mixture was stirred for one hour for the formation of the dicerium salt.…”

Section: Methodsmentioning

confidence: 99%