- Catalytic deoxygenation of bio-based 3-hydroxydecanoic acid to secondary alcohols and alkanes
-
This work comprises the selective deoxygenation of bio-derivable 3-hydroxydecanoic acid to either linear alkanes or secondary alcohols in aqueous phase and H2-atmosphere over supported metal catalysts. Among the screened catalysts, Ru-based systems were identified to be most active. By tailoring the catalyst, the product selectivity could be directed to either secondary alcohols or linear alkanes. In the absence of a Br?nsted acidic additive, 2-nonanol and 3-decanol were accessible with a yield of 79% and 6% respectively, both of which can be used in food and perfume industries as flavoring agents and fragrances. To produce alkanes, we successfully synthesized a bifunctional Ru/HZSM-5 catalyst. The acidic zeolite support facilitated the dehydration of the intermediary formed alcohols to alkenes, while the following hydrogenation occurred at the Ru centers. Thus, full 3-hydroxydecanoic acid deoxygenation to nonane and decane, which are both well-established as diesel and jet fuels, was achieved with up to 72% and 12% yield, respectively.
- Artz, Jens,Brosch, Sebastian,Golchert, Christiane,Hergesell, Adrian H.,Mensah, Joel B.,Palkovits, Regina
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supporting information
p. 3522 - 3531
(2020/08/28)
-
- Photoinduced Hydroxylation of Organic Halides under Mild Conditions
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Presented in this paper is photoinduced hydroxylation of organic halides, providing a mild access to a range of functionalized phenols and aliphatic alcohols. These reactions generally proceed under mild reaction conditions with no need for a photocatalyst or a strong base and show a wide substrate scope as well as excellent functional group tolerance. This work highlights the unique role of NaI that allows a challenging transformation to proceed under mild reaction conditions.
- Cai, Yue-Ming,Xu, Yu-Ting,Zhang, Xin,Gao, Wen-Xia,Huang, Xiao-Bo,Zhou, Yun-Bing,Liu, Miao-Chang,Wu, Hua-Yue
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supporting information
p. 8479 - 8484
(2019/10/16)
-
- ALKANE OXIDATION BY MODIFIED HYDROXYLASES
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This invention relates to modified hydroxylases. The invention further relates to cells expressing such modified hydroxylases and methods of producing hydroxylated alkanes by contacting a suitable substrate with such cells.
- -
-
Paragraph 0323; 0324
(2016/02/16)
-
- Dinuclear Di(N-heterocyclic carbene) iridium(III) complexes as catalysts in transfer hydrogenation
-
Two novel di(N-heterocyclic carbene) complexes of formula (μ-PyrIm-CH2-ImPyr)[IrCp?Cl]2(PF6)2 (1) and μ-MeIm-CH2(p-C6H2)CH2-ImMe[IrCp? Cl]2 (2) (Im = imidazol-2-ylidene) have been synthesised by transmetallation of the dicarbene ligand from the corresponding dicarbene silver complex, using [IrCp?(μ-Cl)Cl]2 as an iridium precursor. The structure of complex 2 has been determined by X-ray diffraction and is characterized by a double ortho-metallation of the p-xylylene bridge between the carbene units. Both complexes show good activity in the transfer hydrogenation of ketones to alcohols in 2-propanol. Dinuclear iridium(III) complexes bearing a bridging di(NHC) ligand have been synthesised and tested as catalysts in transfer hydrogenation reactions.
- Volpe, Andrea,Baldino, Salvatore,Tubaro, Cristina,Baratta, Walter,Basato, Marino,Graiff, Claudia
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p. 247 - 251
(2016/01/20)
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- Catalytic enantioselective addition of methyltriisopropoxititanium to aldehydes
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An efficient catalyst for the enantioselective synthesis of chiral methyl carbinols from aldehydes is presented. The system uses methyltriisopropoxytitanium as a nucleophile and a readily available binaphthyl derivative as a chiral ligand. The enantioselective methylation of both aromatic and aliphatic aldehydes proceeds with good yields and high enantioselectivities under mild conditions.
- Veguillas, Marcos,Solà, Ricard,Fernández-Iba?ez, M. ángeles,Maciá, Beatriz
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p. 643 - 648
(2016/07/11)
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- Catalytic Asymmetric Addition of Organolithium Reagents to Aldehydes
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Herein we report an efficient catalytic system for the titanium-promoted enantioselective addition of organolithium reagents to aldehydes, based on chiral Ar-BINMOL ligands. Unprecedented yields and enantioselectivities are achieved in the alkylation reactions of aliphatic aldehydes. Remarkably, methyllithium can be added to a wide variety of aromatic and aliphatic aldehydes, providing versatile chiral methyl carbinol units in a simple one-pot procedure under mild conditions and in very short reaction times.
- Veguillas, Marcos,Solà, Ricard,Shaw, Luke,Maciá, Beatriz
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p. 1788 - 1794
(2016/04/05)
-
- SELF-REGENERATING ANTIOXIDANT CATALYSTS AND METHODS OF USING THE SAME
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The present invention relates to self-regenerating antioxidant catalysts and methods of using the same.
- -
-
Paragraph 0127
(2016/06/28)
-
- Identification of an ε-keto ester reductase for the efficient synthesis of an (R)-α-lipoic acid precursor
-
Abstract A novel reductase (CpAR2) with unusually high activity toward an ε-keto ester, ethyl 8-chloro-6-oxooctanoate, was isolated from Candida parapsilosis. The asymmetric reduction of ethyl 8-chloro-6-oxooctanoate using Escherichia coli cells coexpressing CpAR2 and glucose dehydrogenase genes gave ethyl (R)-8-chloro-6-hydroxyoctanoate, a key precursor for the synthesis of (R)-α-lipoic acid, in high space-time yield (530 gL-1d-1) and with excellent enantiomeric excess (>99%). This bioprocess was shown to be viable on a 10-L scale. This method provides a greener and more cost-effective method for the industrial production of (R)-α-lipoic acid.
- Zhang, Yu-Jun,Zhang, Wen-Xia,Zheng, Gao-Wei,Xu, Jian-He
-
supporting information
p. 1697 - 1702
(2015/06/02)
-
- Identification of key residues in Debaryomyces hansenii carbonyl reductase for highly productive preparation of (S)-aryl halohydrins
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Key residues of Debaryomyces hansenii carbonyl reductase in the determination of the reducing activity towards aryl haloketones were identified through combinatorial mutation of conserved residues. This study provides a green and efficient biocatalyst for the synthesis of (S)-aryl halohydrins.
- Xu, Guo-Chao,Shang, Yue-Peng,Yu, Hui-Lei,Xu, Jian-He
-
supporting information
p. 15728 - 15731
(2015/11/02)
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- New Type of 2,6-Bis(imidazo[1,2-a]pyridin-2-yl)pyridine-Based Ruthenium Complexes: Active Catalysts for Transfer Hydrogenation of Ketones
-
Neutral and cationic ruthenium(II) complexes bearing a symmetrical 2,6-bis(imidazo[1,2-a]pyridin-2-yl)pyridine were synthesized and structurally characterized by NMR analysis and X-ray crystallographic determinations. These complexes have exhibited good catalytic activity in the transfer hydrogenation of ketones. In refluxing isopropyl alcohol, the conversion of the substrates reached up to 99%, and a TOF value of 356400 h-1 with 0.1 mol % catalyst was achieved. (Figure Presented).
- Li, Ke,Niu, Jun-Long,Yang, Ming-Ze,Li, Zhen,Wu, Li-Yuan,Hao, Xin-Qi,Song, Mao-Ping
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p. 1170 - 1176
(2015/04/27)
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- A novel P450-based biocatalyst for the selective production of chiral 2-alkanols
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A P450 monooxygenase from Nocardia farcinica (CYP154A8) catalyses the stereo- and regioselective hydroxylation of n-alkanes, still a challenging task in chemical catalysis. In a biphasic reaction system, the regioselectivity for the C2-position of C7-C9 alkanes was over 90%. The enzyme showed strict S-selectivity for all tested substrates, with enantiomeric excess (ee) of up to 91%. This journal is the Partner Organisations 2014.
- Von Bühler, Clemens J.,Urlacher, Vlada B.
-
supporting information
p. 4089 - 4091
(2014/04/03)
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- Facile access to chiral alcohols with pharmaceutical relevance using a ketoreductase newly mined from Pichia guilliermondii
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Chiral secondary alcohols with additional functional groups are frequently required as important and valuable synthons for pharmaceuticals, agricultural and other fine chemicals. With the advantages of environmentally benign reaction conditions, broad reaction scope, and high stereoselectivity, biocatalytic reduction of prochiral ketones offers significant potential in the synthesis of optically active alcohols. A CmCR homologous carbonyl reductase from Pichia guilliermondii NRRL Y-324 was successfully overexpressed. Substrate profile characterization revealed its broad substrate specificity, covering aryl ketones, aliphatic ketones and ketoesters. Furthermore, a variety of ketone substrates were asymmetrically reduced by the purified enzyme with an additionally NADPH regeneration system. The reduction system exhibited excellent enantioselectivity (>99% ee) in the reduction of all the aromatic ketones and ketoesters, except for 2-bromoacetophenone (93.5% ee). Semi-preparative reduction of six ketones was achieved with high enantioselectivity (>99% ee) and isolation yields (>80%) within 12 h. This study provides a useful guidance for further application of this enzyme in the asymmetric synthesis of chiral alcohol enantiomers. Copyright
- Xu, Guochao,Yu, Huilei,Xu, Jianhe
-
p. 349 - 354
(2013/08/22)
-
- Continuous biphasic enzymatic reduction of aliphatic ketones
-
Biphasic reactions offer an attractive alternative for the utilisation of enzymes for conversion of hardly water soluble substrates. Especially, the alcohol dehydrogenase from Lactobacillus brevis was successfully used for the reductive synthesis of enantiopure secondary aliphatic alcohols. With the enzymatic catalyst and the cofactor effectively retained in the reactive aqueous phase, the continuous operation was demonstrated by continuous addition and withdrawal of the non-reactive phase. The four tested substrates 2-heptanone, 2-octanone, 2-nonanone, and 2-decanone showed that the space time yield and turnover numbers (TON) of the enzyme decrease as the availability of the substrate decreases with increasing partition coefficients. Nevertheless, a TONLbADH of up to 478 × 103 could be achieved. Remarkably, the cofactor utilisation turned out to be very high and a TON NADP+ of more than 20 × 103 was easily achievable for both 2-heptanone and 2-octanone by substrate coupled cofactor regeneration with excess of 2-propanol.
- Leuchs, Susanne,Nonnen, Thomas,Dechambre, Dominique,Na'Amnieh, Shukralla,Greiner, Lasse
-
-
- Synthesis of [RuX(CO)(dppp)(NN)]Cl (X = H, Cl; NN = en, ampy) complexes and their use as catalysts for transfer hydrogenation
-
The monocarbonyl hydride complexes [RuH(CO)(dppp)(NN)]Cl (dppp = Ph 2P(CH2)3PPh2; NN = ethylenediamine (en), 1; NN = 2-aminomethylpyridine (ampy), 3) have been isolated in high yield by reaction of RuHCl(CO)(PPh3)(dppp) with en and ampy, respectively, in toluene at reflux. The chloride complexes [RuCl(CO)(dppp)(NN)]Cl (NN = en, 2; NN = ampy, 4) have been obtained quantitatively by dissolution of 1 in CH 2Cl2 and 3 in CHCl3, through substitution of the hydride with a chloride and isomerization. Treatment of 4 with NaOiPr in 2-propanol at room temperature cleanly leads to the hydride complex 3. Complexes 1-4 have been proven to be robust and productive catalysts for the transfer hydrogenation of alkyl aryl, diaryl, dialkyl, and cyclic ketones using 0.2-0.004 mol % of catalyst and in the presence of 2 mol % of NaOiPr, affording TOF values up to 2.5 × 105 h-1.
- Zhang, Shuanming,Baldino, Salvatore,Baratta, Walter
-
p. 5299 - 5304
(2013/11/06)
-
- Ruthenium-catalyzed hydroformylation/reduction of olefins to alcohols: Extending the scope to internal alkenes
-
In the presence of 2-phosphino-substituted imidazole ligands and Ru 3(CO)12 or Ru(methylallyl)2(COD) direct hydroformylation and hydrogenation of alkenes to alcohols takes place. In addition to terminal alkenes, also more challenging internal olefins are converted preferentially to industrially important linear alcohols in high yield (up to 88%) and regioselectivity (n:iso up to 99:1).
- Wu, Lipeng,Fleischer, Ivana,Jackstell, Ralf,Profir, Irina,Franke, Robert,Beller, Matthias
-
supporting information
p. 14306 - 14312
(2013/10/21)
-
- "One-pot" reductive lactone alkylation provides a concise asymmetric synthesis of chiral isoprenoid targets
-
An efficient method, based on nucleophilic addition to lactones followed by modified in situ Clemmensen reduction, provides a short synthetic route to chiral isoprenoid targets. The efficacy of this method has been exemplified through the synthesis of several targets including the commercial fragrance Rosaphen, the side chain of Zaragozic acid C, the cotton leaf sex pheromone, and the side chains of vitamin E.
- Cao, Jia,Perlmutter, Patrick
-
supporting information
p. 4327 - 4329
(2013/09/24)
-
- Ionic liquid facilitates biocatalytic conversion of hardly water soluble ketones
-
Ionic liquids represent a promising alternative to conventional cosolvents as biocompatible solubilisers for biocatalysis. This was shown using water miscible ionic liquids to facilitate the stereoselective reduction of hardly water soluble, aliphatic ketones catalysed by the alcohol dehydrogenase from Lactobacillus brevis. Ten ionic liquids were screened for activity and solubility. Improved storage stabilities besides improved enzyme activities, as well as reduced substrate surplus and product inhibitions were found, while applying the most promising AMMOENG 101 in more detailed investigations. Batch reactions with cofactor regeneration via a glucose dehydrogenase showed increased reaction rates; thus underlining the positive influence of AMMOENG 101. For (R)-3-octanol, (R)-2-nonanol, (R)-2-decanol, and (R)-2-octanol space time yields between 250 and 350 mmol L-1 d -1 were achieved.
- Kohlmann, Christina,Robertz, Nora,Leuchs, Susanne,Dogan, Zuebeyde,Luetz, Stephan,Bitzer, Katrin,Na'Amnieh, Shukrallah,Greiner, Lasse
-
experimental part
p. 147 - 153
(2011/10/08)
-
- Utilising hardly-water soluble substrates as a second phase enables the straightforward synthesis of chiral alcohols
-
So far, the alcohol dehydrogenase-catalysed conversion of longer chain aliphatic substrates has been challenging due to their low solubility in aqueous solution. However, by utilising the ketone directly as a second organic phase, the straightforward synthesis of long chain aliphatic chiral alcohols is enabled. The Royal Society of Chemistry.
- Kohlmann, Christina,Robertz, Nora,Leuchs, Susanne,Greiner, Lasse,Na'Amnieh, Shukralla
-
supporting information; experimental part
p. 3093 - 3095
(2011/12/05)
-
- Synthesis, structure and catalytic properties of CNN pincer palladium(II) and ruthenium(II) complexes with N-substituted-2-aminomethyl-6-phenylpyridines
-
N-substituted-2-aminomethyl-6-phenylpyridines 2a-c have been easily prepared from commercially available 6-bromo-2-picolinaldehyde in two steps. Reaction of 2a-c with PdCl2 in toluene in the presence of triethylamine gave the CNN pincer Pd(ii) complexes 3a-c in 18-28% yields. The CNN pincer Ru(ii) complex 5 containing a Ru-NHR functionality could be obtained in a 71% yield by treatment of 2c with a Ru(ii) precursor instead of PdCl 2. Additionally, the related CNN pincer Ru(ii) complex 7 containing a Ru-NH2 functionality has been synthesized by the reaction of 2-aminomethyl-6-phenylpyridine with the same Ru(ii) precursor in a 68% yield. All the new compounds were characterized by elemental analysis (MS for ligands), 1H, 13C NMR, 31P{1H} NMR (for Ru complexes) and IR spectra. Molecular structures of Pd complex 3c as well as Ru complexes 5 and 7 have been determined by X-ray single-crystal diffraction. The obtained Pd complexes 3a-c were effective catalysts for the allylation of aldehydes as well as for three-component allylation of aldehydes, arylamines and allyltributyltin and their activity was found to be much higher than a related NCN Pd(ii) pincer in the allylation of aldehyde. On the other hand, the two new CNN pincer Ru(ii) complexes 5 and 7 displayed excellent catalytic activity in the transfer hydrogenation of ketones in refluxing 2-propanol with the latter being much more active. The final TOF values were up to 4510 h-1 with 0.01 mol% of 5 and 220800 h-1 with 0.005 mol% of 7, respectively. The Royal Society of Chemistry 2011.
- Wang, Tao,Hao, Xin-Qi,Zhang, Xiao-Xue,Gong, Jun-Fang,Song, Mao-Ping
-
experimental part
p. 8964 - 8976
(2011/10/31)
-
- Regioselective ω-hydroxylation of medium-chain n-alkanes and primary alcohols by CYP153 enzymes from Mycobacterium marinum and Polaromonas sp. strain JS666
-
The oxofunctionalization of saturated hydrocarbons is an important goal in basic and applied chemistry. Biocatalysts like cytochrome P450 enzymes can introduce oxygen into a wide variety of molecules in a very selective manner, which can be used for the synthesis of fine and bulk chemicals. Cytochrome P450 enzymes from the CYP153A subfamily have been described as alkane hydroxylases with high terminal regioselectivity. Here we report the product yields resulting from C5-C12 alkane and alcohol oxidation catalyzed by CYP153A enzymes from Mycobacterium marinum (CYP153A16) and Polaromonas sp. (CYP153A P. sp.). For all reactions, byproduct formation is described in detail. Following cloning and expression in Escherichia coli, the activity of the purified monooxygenases was reconstituted with putidaredoxin (CamA) and putidaredoxin reductase (CamB). Although both enzyme systems yielded primary alcohols and α,ω-alkanediols, each one displayed a different oxidation pattern towards alkanes. For CYP153A P. sp. a predominant ω-hydroxylation activity was observed, while CYP153A16 possessed the ability to catalyze both ω-hydroxylation and α,ω- dihydroxylation reactions.
- Scheps, Daniel,Honda Malca, Sumire,Hoffmann, Helen,Nestl, Bettina M.,Hauer, Bernhard
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scheme or table
p. 6727 - 6733
(2011/11/30)
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- Preparation of passion fruit-typical 2-alkyl ester enantiomers via lipase-catalyzed kinetic resolution
-
The preparation of ester enantiomers (acetates, butanoates, hexanoates and octanoates) of the secondary alcohols 2-pentanol, 2-heptanol and 2-nonanol via lipase-catalyzed kinetic resolutions was investigated. Conversion rates and stereochemical courses of esterification and hydrolysis reactions catalyzed by commercially available enzyme preparations were followed for the homologous series of these passion fruit-typical 2-alkyl esters by capillary gas chromatography using heptakis(2,3-di-O-methyl-6-O-tert-butyldimethylsilyl)- β-cyclodextrin as chiral stationary phase. An efficient method was developed to prepare the ester enantiomers via lipase-catalyzed esterifications: optically pure (R)-2-alkyl esters (ee > 99.9%) were obtained by esterification of the racemic alcohols with enantioselective Candida antarctica lipase B (immobilized) as catalyst. The subsequent esterification of the unreacted alcohols using lipase from Candida cylindracea yielded the optically enriched (S)-esters (ee > 81.4%). The separation of the products via liquid solid chromatography using a mixture of silica gel and aluminum oxide (basic) resulted in high chemical purities and yields (> 40 mol %).
- Strohalm, Hedwig,Dold, Susanne,Pendzialek, Kathrin,Weiher, Monika,Engel, Karl-Heinz
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p. 6328 - 6333
(2011/08/09)
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- Escherichia coli BioH: A highly enantioselective and organic solvent tolerant esterase for kinetic resolution of sec-alcohols
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Escherichia coli BioH, which is obligatory for biotin synthesis, was found to be an organic solvent tolerant esterase with high enantioselectivity for the kinetic resolution of sec-alcohols using free enzyme powder. With this esterase, a variety of racemic sec-alcohols were efficiently resolved with ee values of up to 99%.
- Wang, Bo,Tang, Xiaoling,Liu, Ji,Yu, Hongwei
-
supporting information; experimental part
p. 6360 - 6364
(2011/01/04)
-
- Asymmetric reduction of aliphatic ketones and acyl silanes using chiral anti-pentane-2,4-diol and a catalytic amount of 2,4-dinitrobenzenesulfonic acid
-
Aliphatic ketones were reduced to the corresponding secondary alcohols by using anti-1,3-diol and a catalytic amount of 2,4-dinitrobenzenesulfonic acid (DNBSA) in benzene at reflux. Addition of 1-octanethiol in that media improved the efficiency of the reduction. Asymmetric reduction of aliphatic ketones was performed by using chiral anti-pentane-2,4-diol, and highly asymmetric induction (up to >99% ee) was observed in the reduction of tert-alkyl ketones. Asymmetric reduction of acyl silanes using chiral anti-pentane-2,4-diol and DNBSA proceeded efficiently in the absence of octanethiol and the corresponding α-silyl alcohols were obtained in high yields with high ees.
- Matsuo, Jun-Ichi,Hattori, Yu,Hashizume, Mio,Ishibashi, Hiroyuki
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experimental part
p. 6062 - 6069
(2010/10/02)
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- Enantiocomplementary inverting sec-alkylsulfatase activity in cyano- and thio-bacteria Synechococcus and Paracoccus spp.: selectivity enhancement by medium engineering
-
Whole resting cells of cyano- and thio-bacteria Synechococcus and Paracoccus spp. were shown to possess inverting alkylsulfatase activity for a broad spectrum of sec-alkylsulfate esters, which furnished either (R)- or (S)-sec-alcohols from the correspondi
- Gadler, Petra,Reiter, Tamara C.,Hoelsch, Kathrin,Weuster-Botz, Dirk,Faber, Kurt
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experimental part
p. 115 - 118
(2009/05/30)
-
- Mechanistic investigation of the Candida albicans CCT 0776 stereoinversion system and application to obtain enantiopure secondary alcohols
-
Phenylethanol deracemization with Candida albicans CCT 0776 whole cells yields the (R)-enantiomer in over 99% enantiomeric excess and 98% yield. The deracemization process involves, in the first step, a fast, highly (S)-selective oxidation (NADP and O2 dependent) and, in the second step, a slower partially (S)-selective reduction (NADH dependent) of the intermediate ketone. The process was extended to other 2-alkanols, 1,2-diols and 1,3-diols and, with the exception of 1,3-diol (unreactive), the enantiomeric excess and yield of the deracemization were about 99% and 62-98%, respectively.
- Mantovani, Simone M.,Angolini, Celio F.F.,Marsaioli, Anita J.
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experimental part
p. 2635 - 2638
(2010/03/30)
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- Enantioselective reduction of prochiral ketones employing sprouted Pisum sativa as biocatalyst
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Sprouted green peas have been used for the first time as biocatalysts for enantioselective reduction of prochiral ketones. The reactions are highly enantioselective to furnish chiral alcohols in good yields. The sprouted peas as biocatalysts are a cheap and easy way for generating some interesting chiral alcohols. This process is efficient and convenient to produce chiral secondary alcohols in water. Georg Thieme Verlag Stuttgart.
- Yadav, Jhillu S.,Subba Reddy, Basi V.,Sreelakshmi, Chittamuru,Rao, Adari Bhaskar
-
experimental part
p. 1881 - 1885
(2010/01/16)
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- Efficient and chemoselective reduction of carbonyl compounds with supported gold catalysts under transfer hydrogenation conditions
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A new heterogeneous catalytic transfer hydrogenation (CTH) system, consisting of a non-flammable supported Au catalyst along with 2-propanol as the hydrogen donor, was proven to be effective for chemoselective reduction of a wide range of aromatic ketones and aldehydes to the corresponding alcohols. The Royal Society of Chemistry.
- Su, Fang-Zheng,He, Lin,Ni, Ji,Cao, Yong,He, He-Yong,Fan, Kang-Nian
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supporting information; scheme or table
p. 3531 - 3533
(2009/02/05)
-
- Synthesis of new NHC-rhodium and iridium complexes derived from 2,2′-diaminobiphenyl and their catalytic activities toward hydrosilylation of ketones
-
Four new N-heterocyclic carbene (NHC)-rhodium and iridium complexes derived from 2,2′-diaminobiphenyl have been successfully synthesized and their structures have been unambiguously characterized by X-ray diffraction. Their catalytic activities for hydrosilylation of ketones with diphenylsilane were investigated. It was found that NHC-rhodium complex (6) is the best one among the four catalysts for the reduction of ketones.
- Chen, Tao,Liu, Xu-Guang,Shi, Min
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p. 4874 - 4880
(2008/02/01)
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- Enzymatic ketone reduction: mapping the substrate profile of a short-chain alcohol dehydrogenase (YMR226c) from Saccharomyces cerevisiae
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A short-chain alcohol dehydrogenase (YMR226c) from Saccharomyces cerevisiae was cloned and expressed in Escherichia coli, and the encoded protein was purified. The activity and enantioselectivity of this recombinant enzyme were evaluated with a series of ketones. The alcohol dehydrogenase (YMR226c) was found to effectively catalyze the enantioselective reductions of aryl-substituted acetophenones, α-chloroacetophenones, aliphatic ketones, and α- and β-ketoesters. While the enantioselectivity for the reduction of β-ketoesters was moderate, the acetophenone derivatives, aromatic α-ketoesters, some substituted α-chloroacetophenones, and aliphatic ketones were reduced to the corresponding chiral alcohols with excellent enantioselectivity. The enantiopreference of this enzyme generally followed Prelog's rule for the simple ketones. The ester functionality played some role in determining the enzyme's enantiopreference for the reduction of α- and β-ketoesters. The present study serves as a valuable guidance for the future applications of this versatile biocatalyst.
- Yang, Yan,Zhu, Dunming,Piegat, Timothy J.,Hua, Ling
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p. 1799 - 1803
(2008/02/12)
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- Synthesis of a fluorous ligand and its application for asymmetric addition of dimethylzinc to aldehydes
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A new fluorous ligand was synthesized from the acetonide of dimethyl tartarate, which showed excellent asymmetric induction on the addition of dimethylzinc to aldehydes. This ligand will be useful for synthesis of bioactive compounds with a methyl carbinol moiety. It could be recycled without using a fluorous solvent or a fluorous column.
- Sokeirik, Yasser S.,Mori, Hiroyuki,Omote, Masaaki,Sato, Kazuyuki,Tarai, Atsushi,Kumadaki, Itsumaro,Ando, Akira
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p. 1927 - 1929
(2008/02/02)
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- Stereoselective enzymatic synthesis of chiral alcohols with the use of a carbonyl reductase from Candida magnoliae with anti-prelog enantioselectivity
-
In our effort to search for carbonyl reductases with anti-Prelog enantioselectivity, the activity and enantioselectivity of a carbonyl reductase from Candida magnoliae have been examined with various ketones of diverse structures. This carbonyl reductase catalyzed the reduction of a series of ketones, α-and β-ketoesters, to anti-Prelog configurated alcohols in excellent optical purity. The usefulness of this carbonyl reductase has been demonstrated by synthesis of several chiral alcohol intermediates of pharmaceutical importance.
- Zhu, Dunming,Yang, Yan,Hua, Ling
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p. 4202 - 4205
(2007/10/03)
-
- Maximise equilibrium conversion in biphasic catalysed reactions: How to obtain reliable data for equilibrium constants?
-
For the prediction and optimisation of the equilibrium conversion in biphasic catalysed reactions, the equilibrium constant of the desired reaction and the partition coefficients of all reactants have to be known. Within this contribution we have examined the alcohol dehydrogenase-catalysed reduction of several linear and aromatic ketones in biphasic reaction media with respect to equilibrium conversion. In this example, the equilibrium constant can be expressed in terms of differences in oxidation-reduction potentials ΔE0. However, for a large variety of organic compounds, these data are quite rare in the literature. To overcome this lack of data, we have utilised methods of computational chemistry to calculate data for the Gibbs free energy ΔGR leading to the equilibrium constants of a homologous series of linear ketones. To obtain comparable data for the reduction of substituted acetophenone derivatives, the Hammett relation leads to the necessary equilibrium constants. Furthermore, we compare the equilibrium conversions of a set of cofactor regeneration methods for the alcohol dehydrogenase-catalysed reductions. These results lead to a time-saving experimental design for the enantioselective reduction of 2-octanone to (R)-2-octanol on a preparative scale utilising biphasic reaction conditions.
- Eckstein,Lembrecht,Schumacher,Eberhard,Spiess,Peters,Roosen,Greiner,Leitner,Kragl
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p. 1597 - 1604
(2007/10/03)
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- Efficient method for the deprotection of tert-butyldimethylsilyl ethers with TiCl4-Lewis base complexes: Application to the synthesis of 1β-methylcarbapenems
-
TiCl4-Lewis base (AcOEt, CH3NO2) complexes smoothly deprotected tert-butyldimethylsilyl (TBDMS) ethers. The reaction velocity with these complexes, which seemed less reactive due to the influence of Lewis bases, was considerably greater than that with TiCl4 alone. Selective desilylations between aliphatic and aromatic TBDMS ethers (1 and 5), between 1 and benzyl, allyl, tosyl, methoxyphenyl, and chloroacetyl ethers (13, 14, 15, 16, and 17), and between TBDMS and TBDPS ethers (18 and 19) were successfully performed. Desilylation of TBDMS-aldol, acyloin, and β-lactam analogues 9-12 proceeded smoothly due to anchimeric assistance by the neighboring carbonyl groups. The present method was successfully applied to the practical synthesis of 1β-methylcarbapenems 20a′-f′.
- Iida, Akira,Okazaki, Hiroki,Misaki, Tomonori,Sunagawa, Makoto,Sasaki, Akira,Tanabe, Yoo
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p. 5380 - 5383
(2007/10/03)
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- Engineering cytochrome P450 BM3 for terminal alkane hydroxylation
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Enzymes that catalyze the terminal hydroxylation of alkanes could be used to produce more valuable chemicals from hydrocarbons. Cytochrome P450 BM3 from Bacillus megaterium hydroxylates medium-chain fatty acids at subterminal positions at high rates. To engineer BM3 for terminal alkane hydroxylation, we performed saturation mutagenesis at selected active-site residues of a BM3 variant that hydroxylates alkanes. Recombination of beneficial mutations generated a library of BM3 mutants that hydroxylate linear alkanes with a wide range of regioselectivities. Mutant 77-9H exhibits 52% selectivity for the terminal position of octane. This regioselectivity is octane-specific and does not transfer to other substrates, including shorter and longer hydrocarbons or fatty acids. These results show that BM3 can be readily molded for regioselective oxidation.
- Meinhold, Peter,Peters, Matthew W.,Hartwick, Adam,Hernandez, Alisha R.,Arnold, Frances H.
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p. 763 - 772
(2007/10/03)
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- Highly enantioselective sec-alkyl sulfatase activity of the marine planctomycete Rhodopirellula baltica shows retention of configuration
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(Chemical Equation Presented) Hydrolytic enzymes: The marine planctomycete Rhodopirellula baltica DSM 10527 displays high stereo- and enantioselective alkyl sulfatase activity towards (±)-sec-alkyl sulfates with retention of configuration through cleavage of their S-O bond (see scheme; pathway B), whereas inversion of configuration is observed upon cleavage of the C-O bond (pathway A).
- Wallner, Sabine R.,Bauer, Marga,Wuerdemann, Chris,Wecker, Patricia,Gloeckner, Frank O.,Faber, Kurt
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p. 6381 - 6384
(2007/10/03)
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- A high loading sulfonic acid-functionalized ordered nanoporous silica as an efficient and recyclable catalyst for chemoselective deprotection of tert-butyldimethylsilyl ethers
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A high loading sulfonic acid-functionalized ordered nanoporous silica efficiently catalyzes the deprotection of a variety of alcoholic TBDMS (tert-butyldimethylsilyl)ethers in methanol. The catalyst shows high thermal stability (up to 240°C) and can be recovered and reused for at least seven reaction cycles without loss of reactivity. This method can be used to deprotect TBDMS ethers of alcohols in the presence of TBDMS ethers of phenols.
- Karimi, Babak,Zareyee, Daryoush
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p. 4661 - 4665
(2007/10/03)
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- Chemoselective reduction of aldehydes in the presence of ketones with NaBH4 in polyethylene glycol dimethyl ethers
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Aldehydes and ketones were treated with NaBH4 in polyethylene glycol dimethyl ethers (PEGDME) to give the corresponding alcohols in good yields. Chemoselective reduction of aldehydes in the presence of ketones was described.
- Tanemura, Kiyoshi,Suzuki, Tsuneo,Nishida, Yoko,Satsumabayashi, Koko,Horaguchi, Takaaki
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p. 867 - 872
(2007/10/03)
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- Highly enantioselective stereo-inverting sec-alkylsulfatase activity of hyperthermophilic Archaea
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rac-sec-Alkyl sulfate esters 1a-8a were resolved in low to excellent enantioselectivities with E-values up to > 200 using whole cells of aerobically-grown hyperthermophilic sulfur-metabolizers, such as Sulfolobus solfataricus DSM 1617, Sulfolobus shibatae DSM 5389 and, most notably, Sulfolobus acidocaldarius DSM 639. Significantly enhanced selectivities were obtained using cells grown on sucrose-enriched Brock-medium. The stereochemical course of this biohydrolysis was shown to proceed with strict inversion of configuration, thus the preferred (R)-enantiomers were converted into the corresponding (S)-sec-alcohols to furnish a homochiral product mixture. The Royal Society of Chemistry 2005.
- Wallner, Sabine R.,Nestl, Bettina M.,Faber, Kurt
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p. 2652 - 2656
(2007/10/03)
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- Synthesis of novel axially chiral Rh-NHC complexes derived from BINAM and application in the enantioselective hydrosilylation of methyl ketones
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Novel axially chiral Rh N-heterocyclic carbene complexes were prepared from axially dissymmetric 1,1′-binaphthalenyl-2,2′-diamine and applied in the Rh-catalyzed enantioselective hydrosilylation of methyl ketones. The corresponding sec-alcohols can be obtained in high yields with good to excellent ee.
- Duan, Wei-Liang,Shi, Min,Rong, Guo-Bin
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p. 2916 - 2917
(2007/10/03)
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- Biocatalytic asymmetric hydrogen transfer employing Rhodococcus ruber DSM 44541
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Nonracemic sec-alcohols of opposite absolute configuration were obtained either by asymmetric reduction of the corresponding ketone using 2-propanol as hydrogen donor or by enantioselective oxidation through kinetic resolution of the rac-alcohol using acetone as hydrogen acceptor employing whole lyophilized cells of Rhodococcus ruber DSM 44541. The microbial oxidation/reduction system exhibits not only excellent stereo- and enantioselectivity but also a broad substrate spectrum. Due to the exceptional tolerance of the biocatalyst toward elevated concentrations of organic materials (solvents, substrates and cosubstrates), the process is highly efficient. The simple preparation of the biocatalyst and its ease of handling turns this system into a versatile tool for organic synthesis.
- Stampfer, Wolfgang,Kosjek, Birgit,Faber, Kurt,Kroutil, Wolfgang
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p. 402 - 406
(2007/10/03)
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- Practical approach to the Meerwein-Ponndorf-Verley reduction of carbonyl substrates with new aluminum catalysts
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Simple mixing of Al(OiPr)3 with the requisite ligand 1 in CH2Cl2 at room temperature smoothly generates the new, powerful aluminum catalyst 2, which efficiently catalyzes Meerwein-Ponndorf-Verley (MPV) reduction of various carbonyl substrates under mild conditions (see scheme). Scale-up experiments highlight the potential of the new MPV reduction procedure for practical use.
- Ooi, Takashi,Ichikawa, Hayato,Maruoka, Keiji
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p. 3610 - 3612
(2007/10/03)
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- Asymmetric reduction of ketones by Geotrichum candidum in the presence of Amberlite Xad, A solid organic solvent
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Asymmetric reduction of ketones by Geotrichum candidum in the presence of Amberlite XAD, a solid organic solvent, was described. A hydrophobic polymer, XAD, was used as material to control the stereochemical course of microbial reductions. Aliphatic and aromatic ketones were reduced to the corresponding (S)-alcohols in excellent enantiomeric excess (ee) in the presence of XRD while low enantioselectivities were observed in the absence of the polymer.
- Nakamura, Kaoru,Fujii, Mikio,Ida, Yoshiteru
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p. 3205 - 3211
(2007/10/03)
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- Selective dioxygenation of cyclohexane catalysed by hydrogen peroxide and dinuclear iron(III) complexes with μ-alkoxo bridges
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Several dinuclear iron(III) complexes with μ-alkoxo bridges gave predominantly cyclohexyl hydroperoxide in the reaction with cyclohexane and hydrogen peroxide, and similar results were observed when linear n-alkanes, such as n-nonane and n-octane, were used instead of cyclohexane. A mechanism for selective formation of the hydroperoxide is discussed.
- Nishino, Satoshi,Hosomi, Hiroyuki,Ohba, Shigeru,Matsushima, Hideaki,Tokii, Tadashi,Nishida, Yuzo
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p. 1509 - 1513
(2007/10/03)
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- From Highly Enantioselective Monomeric Catalysts to Highly Enantioselective Polymeric Catalysts: Application of Rigid and Sterically Regular Chiral Binaphthyl Polymers to the Asymmetric Synthesis of Chiral Secondary Alcohols
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A 1,1′-binaphthyl-based polymeric chiral catalyst with the most general enantioselectivity for the alkylzinc addition to a broad range of aldehydes has been obtained. This polymer can be easily recovered, and the recycled polymer shows the same catalytic properties as the original polymer. A highly enantioselective catalytic diphenylzinc addition to aldehydes has also been achieved by using the chiral binaphthyl monomer and polymer catalysts. Particularly, the excellent enantioselectivity observed for the addition of diphenylzinc to aromatic aldehydes allows the preparation of optically active diaryl carbinols that are synthetically useful but difficult to access by asymmetric catalysis. A novel asymmetric reduction of ketones catalyzed by the mono- and polybinaphthyl zinc complexes has been discovered. Our work on the asymmetric organozinc addition to aldehydes and the asymmetric reduction of ketones catalyzed by the zinc complexes of chiral binaphthyl monomer (R)-12 and polybinaphthyl (R)-43 has not only provided new methods to prepare optically active secondary alcohols but also demonstrated that incorporation of an enantioselective monomeric catalyst into a rigid and sterically regular polymer structure could almost completely preserve the catalytic properties of the monomeric catalyst. This strategy may find general application in converting existing highly enantioselective monomer catalysts into polymer catalysts of similar enantioselectivity provided that the catalytically active species of the monomer catalysts contain only the monomeric units rather than the aggregates of the monomers. By using this strategy, it is possible to overcome the drawbacks associated with the traditional approach to preparing polymeric chiral catalysts where the microenvironments of the catalytic sites in the polymers are often significantly altered from those in the monomeric catalysts due to the flexible and sterically irregular polymer chains.
- Huang, Wei-Sheng,Hu, Qiao-Sheng,Pu, Lin
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p. 7940 - 7956
(2007/10/03)
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- Practical reduction of carbonyl compounds with NaBH4 and silica gel in an aprotic solvent
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Selective and high-yielding synthesis of alcohols can be easily achieved by the reduction of a variety of ketones and aldehydes with a combination of inexpensive and readily available laboratory reagents, NaBH4 and silica gel, in hexane under mild and neutral conditions.
- Yakabe, Shigetaka,Hirano, Masao,Morimoto, Takashi
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p. 295 - 302
(2007/10/03)
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- Process for the production of chiral unsaturated alcohols in high optical purity
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The catalytic asymmetric hydrogenation of enol esters with a vinyllic or acetylenic substituent proceeds with extremely high enantioselectivity using a Rhodium-chiral bisphosphine catalyst. This is at variance with the hydrogenation of enol esters bearing a saturated substituent, which are hydrogenated with only marginal enantioselectivity under the same conditions.
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- Carbonyl reductase activity exhibited by pig testicular 20β- hydroxysteroid dehydrogenase
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The carbonyl reductase activity exhibited by pig testicular 20β- hydroxysteroid dehydrogenase (20β-HSD) was examined using a recombinant enzyme. Kinetic parameters were obtained for 48 carbonyl group-containing substrates, including aromatic aldehydes, aromatic ketones, cycloketones, quinones, aliphatic aldehydes and aliphatic ketones. 20β-HSD showed a high affinity towards quinones, such as 9,10-phenanthrenequinone, α- naphthoquinone and menadione (K(m) values of 4, 2 and 5 μM, respectively), and the substrate utilization efficiency (V(max)/K(m)) of the enzyme against these quinones was very high. Cyclohexanone and 2-methylcyclohexanone were also reduced with a high V(max)/K(m) value, but not cyclopentanone or 2- methylcyclopentanone. Various aromatic aldehydes and ketones including benzaldehyde- and acetophenone-derivatives were reduced by 20β-HSD. Especially, 4-nitrobenzaldehyde and 4-nitroacetophenone were reduced with high V(max)/K(m) values in the related compounds. The enzyme also reduced the pyridine-derivatives, 2-, 3-, and 4-benzoylpyridine, with the V(max)/K(m) value for 2-benzoylpyridine being the highest. 20β-HSD reduced aliphatic aldehydes and aliphatic ketones, but was more effective on the former. The correlation between the structure of carbonyl compounds and their substrate V(max)/K(m) is discussed.
- Nakajin, Shizuo,Tamura, Fumihiro,Takase, Noriko,Toyoshima, Satoshi
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p. 1215 - 1218
(2007/10/03)
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- Goat Liver Lipase : An Efficient Biocatalyst for Enantioselective Transesterification of Secondary Alcohols using Vinyl Acetate as Acyl Donor
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Lipase from fresh goat liver has been shown to catalyze enantioselective transesterification of secondary alcohols in hexane using vinyl acetate as acyl source. In most of the cases transesterification takes place with alcohols of R-configuration, whereas in the case of cholesterol only the natural isomer (3S) is acylated with >99% ee.
- Saikia, Anil K.,Bez, Ghanashyam,Bezbarua, Maitreyee S.,Barua, Nabin C.
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p. 937 - 939
(2007/10/03)
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