- Wickerhamomyces subpelliculosus as whole-cell biocatalyst for stereoselective bioreduction of ketones
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Newly isolated strains of Wickerhamomyces subpelliculosus were recognized as excellent whole-cell biocatalyst for bioreduction of various ketones. The biocatalytic properties of the new strains were demonstrated in this study by stereoselective bioreduction of acetophenone 1a, 2-heptanone 1b, phenylacetone 1c, 3,4-dimethoxyphenylacetone 1d and 1-cyclopropyl-2-(2-methoxy-4-nitrophenoxy)ethanone 1e. Our study is the first report on application of W. subpelliculosus as whole-cell biocatalyst for stereoselective bioreduction of prochiral ketones. In these processes, both the freshly harvested cell paste and the lyophilized cell powder were tested as biocatalyst using glucose or 2-propanol at various concentrations as cosubstrates for cofactor regeneration. The newly isolated strains of W. subpelliculosus showed diverse characteristics, including optimal pH, temperature and organic solvent tolerance. Bioreductions of phenylacetone 1c applying glucose as cosubstrate under various mild conditions resulted (S)-1-phenylpropanol [(S)-2c] in good to excellent conversion (c = 63.4%–99.9%) with excellent enantiomeric excess [ee(S)-2c = 98.7%–99.8%].
- Bódai, Viktória,Nagy-Gy?r, László,?rkényi, Róbert,Molnár, Zsófia,Kohári, Szabolcs,Erdélyi, Balázs,Nagymáté, Zsuzsanna,Romsics, Csaba,Paizs, Csaba,Poppe, László,Hornyánszky, Gábor
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p. 206 - 214
(2016/12/09)
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- Chemoenzymatic synthesis of enantiomerically pure syn-configured 1-aryl-3-methylisochroman derivatives
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A two-step synthesis of various enantiomerically pure 1-aryl-3- methylisochroman derivatives was accomplished through asymmetric biocatalytic ketone reduction followed by an oxa-Pictet-Spengler reaction. The compounds were obtained in good to excellent yield (47-92 %) in favor of the syn diastereomers [dr (syn/anti) up to 99:1]. Enantiopure arylpropanols serving as pronucleophiles for the C-C bond-formation step were obtained by biocatalytic reduction by employing enantiocomplementary alcohol dehydrogenases, which gave access to the (S) and (R) enantiomer with up to >99 % conversion and up to >99 % ee. A two-step sequence involving a biocatalytic hydrogen-transfer reduction and a syn-diastereoselective oxa-Pictet-Spengler reaction was established to provide a series of 1-aryl-3-methylchroman derivatives with perfect enantioselectivity; PTSA = para-toluenesulfonic acid. Copyright
- Simon, Robert C.,Busto, Eduardo,Richter, Nina,Belaj, Ferdinand,Kroutil, Wolfgang
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supporting information
p. 111 - 121
(2014/01/06)
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- Organocatalytic approach to (s)-1-arylpropan-2-ols: Enantioselective synthesis of the key intermediate of antiepileptic agent (-)-talampanel
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An efficient organocatalytic route for the preparation of enantioselective synthesis of (S)-1-arylpropan-2-ols derivatives, including the key intermediate of antiepileptic agent (-)-talampanel is described. The key steps involved are L-proline-catalyzed a
- Sawant, Rajiv T.,Waghmode, Suresh B.
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experimental part
p. 2269 - 2277
(2010/09/11)
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- Assignment of the absolute configurations of l-Aryl-2-propanols with the use of phosphoroselenoyl chlorides as chiral derivatizing agents
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Phosphoroselenoyl chloride bearing a l,1′-bi-2-naphthyl group was reacted with racemic 2-alkanols to give the corresponding esters. Based on the multiple combination of their NMR spectra, a method for the assignment of the absolute configuration of 1 -aryl-2-propanols was established. The solidstate conformations of the esters were confirmed by X-ray structure analyses.
- Murai, Toshiaki,Tsuji, Hiromi,Imaizumi, Satoko,Maruyama, Toshifumi
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supporting information; experimental part
p. 524 - 526
(2010/09/05)
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- Stereoselective production of (S)-1-aralkyl- and 1-arylethanols by freshly harvested and lyophilized yeast cells
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Substituted (S)-1-phenyl- 2a-h and (S)-1-benzyl-propan-2-ols 4a and b, and (S)-1-phenylethanol 6 were produced from prochiral ketones 1a-h, 3a,b and 5 by reductions with freshly harvested Zygosaccharomyces rouxii and Debaryomyces hansenii cells. The bioreductions were also performed by lyophilized cells. Comparison of the secondary alcohols from the bioreductions 2b-e,g,h and 4a and authentic (S)-alcohols (S)-2b-e,g,h and (S)-4a synthesized from enantiopure (S)-methyloxirane 7 proved the absolute configuration of the products.
- Erdelyi, Balazs,Szabo, Antal,Seres, Gabor,Birincsik, Laszlo,Ivanics, Jozsef,Szatzker, Gabor,Poppe, Laszlo
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p. 268 - 274
(2007/10/03)
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- Preparation and resolution of a modular class of axially chiral quinazoline-containing ligands and their application in asymmetric rhodium-catalyzed olefin hydroboration
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The preparation and resolution of a series of axially chiral quinazoline-containing ligands is described in which the key steps are the metal-catalyzed naphthyl-phosphorus bond formation, the naphthalene-quinazoline Suzuki coupling, and the preparation of the Suzuki electrophilic components from the corresponding imidate and anthranilic acid. Diastereomeric palladacycles derived from the racemic phosphinamines and (+)-di-μ-chlorobis[(R)- dimethyl(1-(1-naphthyl)ethyl)-aminato-C2,N]dipalladium(II) were separated by fractional crystallization. The configuration of the resulting diastereomers was determined by X-ray crystallographic analysis. Displacement of the resolving agent by reaction with 1,2-bis(diphenylphosphino)ethane afforded enantiopure ligand in each case. Their rhodium complexes were prepared and applied in the enantioselective hydroboration of a range of vinylarenes. The quinazolinap catalysts were found to be extremely active, giving excellent conversions, good to complete regioselectivities, and the highest enantioselectivities obtained to date for several members of the vinylarene class, including cis-β-methylstyrene (97%), cis-stilbene (99%), and indene (99.5%).
- Connolly, David J.,Lacey, Patrick M.,McCarthy, Mary,Saunders, Cormac P.,Carroll, Anne-Marie,Goddard, Richard,Guiry, Patrick J.
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p. 6572 - 6589
(2007/10/03)
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- Optically active 1-phenyl-2-substituted propane derivatives and methods of producing the same
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An (S)-1-phenyl-2-substituted propane derivative shown by the following formula (I) STR1 wherein R1 and R2 represent a lower alkyl group, etc., or R1 and R2 may form together an alkylene group, etc.; R3, R4 and R5 represent a hydrogen atom, etc.; and X represents a hydroxyl group which may be protected with a protective group, or a halogen atom etc., can readily be produced (i) by permitting a microorganism belonging to the genus Torulaspora, the genus Candida, the genus Pichia or the like to act on a phenylacetone derivative and asymmetrically reducing the compound, or (ii) by sterically inverting an (R)-enantiomer. (R,R)-1-phenyl-2-[(2-phenyl-1-methylethyl)amino]ethanol derivative having a high optical purity can easily be obtained from the compound of the formula (I). The ethanol derivative is useful as an anti-obesity agent and the like.
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