- Aromatic Donor-Acceptor Interaction-Based Co(III)-salen Self-Assemblies and Their Applications in Asymmetric Ring Opening of Epoxides
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Aromatic donor-acceptor interaction as the driving force to assemble cooperative catalysts is described. Pyrene/naphthalenediimide functionalized Co(III)-salen complexes self-assembled into bimetallic catalysts through aromatic donor-acceptor interactions and showed high catalytic activity and selectivity in the asymmetric ring opening of various epoxides. Control experiments, nuclear magnetic resonance (NMR) spectroscopy titrations, mass spectrometry measurement, and X-ray crystal structure analysis confirmed that the catalysts assembled based on the aromatic donor-acceptor interaction, which can be a valuable noncovalent interaction in supramolecular catalyst development.
- Liang, Jian,Soucie, Luke N.,Blechschmidt, Daniel R.,Yoder, Aaron,Gustafson, Addie,Liu, Yu
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supporting information
p. 513 - 518
(2019/01/14)
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- Exploring the Biocatalytic Scope of a Novel Enantioselective Halohydrin Dehalogenase from an Alphaproteobacterium
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A gene encoding halohydrin dehalogenase from an alphaproteobacterium (AbHHDH) was identified, cloned and over-expressed in Escherichia coli. AbHHDH was able to catalyze the stereoselective dehalogenation of prochiral and racemic halohydrins. It showed the highest enantioselectivity in the dehalogenation of 20?mM (R,S)-2-bromo-1-phenylethanol, which yielded (S)-2-bromo-1-phenylethanol with 99% ee and 34.5% yield. Moreover, AbHHDH catalyzed the azidolysis of epoxides with low to moderate (S)-enantioselectivity. The highest enantioselectivity (E = 18.6) was observed when (R,S)-benzyl glycidyl ether was used as the substrate. A sequential kinetic resolution catalyzed by HHDH was employed for the synthesis of chiral 1-chloro-3-phenoxy-2-propanol. We prepared enantiopure (S)-isomer with a high enantiopurity of ee > 99% and a yield of 30.7% (E-value: 21.3) by kinetic resolution of 20?mM substrate. The (S)-isomer with 99% ee readily obtained from 40 to 150?mM (R,S)-1-chloro-3-phenoxy-2-propanol. Taken together, the results of this study demonstrate the applicability of this HHDH for the production of optically active compounds. [Figure not available: see fulltext.].
- Xue, Feng,Ya, Xiangju,Xiu, Yuansong,Tong, Qi,Wang, Yuqi,Zhu, Xinhai,Huang, He
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p. 629 - 637
(2019/01/25)
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- Highly enantioselective CALB-catalyzed kinetic resolution of building blocks for β-blocker atenolol
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Both enantiomers of 4-(3-chloro-2-hydroxypropoxy)phenyl)acetamide has been synthesized in 98.5–99% enantiomeric excess by use of lipase B from Candida antarctica as catalyst. The R-alcohol is a building block for the cardioselective β-blocker (S)-atenolol ((S)-2-(4-(2-hydroxy-3-(isopropylamino)propoxy)phenyl)acetamide. Performing kinetic resolutions of 3-chloro-1-phenoxy-2-propanol and 3-bromo-1-phenoxy-2-propanol with vinyl butanoate as acyl donor and the same CALB enzyme, but a different preparation, showed higher E-values than previously reported.
- Lund, Ingvild T.,B?ckmann, P?l L.,Jacobsen, Elisabeth E.
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p. 7288 - 7292
(2016/10/26)
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- Synthesis of enantiopure epoxide by 'one pot' chemoenzymatic approach using a highly enantioselective dehydrogenase
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Enantiopure α-phenethyl alcohols, including aromatic halohydrins, are important chiral building blocks. One of the best approaches to synthesise α-phenethyl alcohols is asymmetric reduction of prochiral ketones by alcohol dehydrogenases (ADHs). The obtained enantiopure halohydrin could be directly used to produce enantiopure epoxide through a base-induced ring-closure reaction, which is an attractive 'one pot' chemoenzymatic method for producing high-yield epoxide. In this study, a novel medium-chain dehydrogenase (KcDH) from Kuraishia capsulate CBS1993 was identified and characterised to show its broad substrate scope and excellent enantioselectivity. KcDH showed activities on 25 substrates of the 26 tested aromatic ketones and heteroaryl ketones, with an enantiomeric excess (ee) >99% and the highest relative activity observed with para-nitro acetophenone. Due to its high enantioselectivity for α-haloketones, a chemoenzymatic method for the synthesis of enantiopure styrene oxide (SO) and phenyl glycidyl ether (PGE) was developed through a base-induced ring-closure reaction on enantiopure halohydrin obtained with KcDH. (R)-SO and (S)-PGE were obtained in 86% and 94% analytical yield, respectively, and both epoxides were obtained with ee >99%. Thus, our results suggested that KcDH may be a promising biocatalyst for the production of multiple enantiopure α-phenethyl alcohols and epoxides.
- Wu, Kai,Chen, Lifeng,Fan, Haiyang,Zhao, Zhiqiang,Wang, Hualei,Wei, Dongzhi
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p. 899 - 904
(2016/02/05)
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- Tuning of the electronic properties of a cyclopentadienylruthenium catalyst to match racemization of electron-rich and electron-deficient alcohols
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The synthesis of a new series of cyclopentadienylruthenium catalysts with varying electronic properties and their application in racemization of secondary alcohols are described. These racemizations involve two key steps: 1) β-hydride elimination (dehydrogenation) and 2) re-addition of the hydride to the intermediate ketone. The results obtained confirm our previous theory that the electronic properties of the substrate determine which of these two steps is rate determining. For an electron-deficient alcohol the rate-determining step is the β-hydride elimination (dehydrogenation), whereas for an electron-rich alcohol the re-addition of the hydride becomes the rate-determining step. By matching the electronic properties of the catalyst with the electronic properties of the alcohol, we have now shown that a dramatic increase in racemization rate can be obtained. For example, electron-deficient alcohol 15 racemized 30 times faster with electron-deficient catalyst 6 than with the unmodified standard catalyst 4. The application of these protocols will extend the scope of cyclopentadienylruthenium catalysts in racemization and dynamic kinetic resolution. Copyright
- Verho, Oscar,Johnston, Eric V.,Karlsson, Erik,Baeckvall, Jan-E.
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experimental part
p. 11216 - 11222
(2011/11/05)
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- Highly active oligomeric Co(salen) catalysts for the asymmetric synthesis of α-aryloxy or α-alkoxy alcohols via kinetic resolution of terminal epoxides
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A mixture of Co(salen) macrocycles, prepared via the ring expansion metathesis oligomerization of salen-functionalized cyclooctene monomers, among the most active soluble catalysts for the hydrolytic kinetic resolution (HKR) of terminal epoxides, is exploited as the catalyst in the ring-opening of epoxides using aliphatic alcohols or phenols as nucleophiles, leading to the direct synthesis of optically active α-aryloxy alcohols or α-alkoxy alcohols. The catalyst is compared to other dimeric, oligomeric and monomeric Co(salen) complexes including a pimelate-linked macrocyclic Co(salen) catalyst and a dimeric Co(salen) catalyst referred to as a bisalen. The catalysts that contain multiple Co(salen) units within a single molecular framework allow for substantial decreases in catalyst loading compared with the monomeric catalyst. The cyclooctene-based Co(salen) macrocycle catalyst allows for good activity and enantioselectivity in the ring-opening of terminal epoxides with phenols as nucleophiles, giving enhanced turnover frequencies relative to many literature catalysts. The cyclooctene-based Co(salen) macrocycle catalyst and the bisalen catalysts are shown to be the most active in the asymmetric ring-opening of (±)1,2-epoxyhexane with methanol, out-performing the other catalysts tested. The Co(salen) macrocycle catalyst is recycled 3 times in this reaction with some loss in activity but no noteworthy change in selectivity.
- Zhu, Xunjin,Venkatasubbaiah, Krishnan,Weck, Marcus,Jones, Christopher W.
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scheme or table
p. 1 - 6
(2010/11/04)
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- Highly active new chiral Co(iii) salen catalysts immobilized by electrostatic interaction with sulfonic acid linkages on ordered mesoporous SBA-16 silica
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New chiral cobalt(iii) salen complexes immobilized via HO 3S-linkers on ordered SBA-16 by electrostatic interactions showed very high activity in enantioselective ring-opening reactions of racemic epoxides.
- Kim, Yong-Suk,Guo, Xiao-Feng,Kim, Geon-Joong
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scheme or table
p. 4296 - 4298
(2011/03/19)
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- Shifting the equilibrium of a biocatalytic cascade synthesis to enantiopure epoxides using anion exchangers
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Hydroxide-loaded anion exchangers have been successfully employed to shift the equilibrium of a one-pot, two-step, two-enzyme cascade reaction affording enantiopure epoxides starting from prochiral α-chloroketones. The α-chloroketones were asymmetrically reduced employing an alcohol dehydrogenase and then transformed further to the corresponding epoxides employing halohydrin dehalogenases. Each epoxide enantiomer could be obtained with up to 93% conversion in enantiomerically pure form (>99% ee). In contrast to previous studies the amount of hydride donor (2-propanol) could be reduced due to favoured halohydrin formation in the reduction of α-chloroketones.
- Schrittwieser, Joerg H.,Lavandera, Ivan,Seisser, Birgit,Mautner, Barbara,Lutje Spelberg, Jeffrey H.,Kroutil, Wolfgang
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experimental part
p. 483 - 488
(2009/07/25)
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- Highly efficient route for enantioselective preparation of chlorohydrins via dynamic kinetic resolution
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(Equation Presented) Dynamic kinetic resolution (DKR) of various aromatic chlorohydrins with the use of Pseudomonas cepacia lipase (PS-C "Amano" II) and ruthenium catalyst 1 afforded chlorohydrin acetates in high yields and high enantiomeric excesses. These optically pure chlorohydrin acetates are useful synthetic intermediates and can be transformed to a range of important chiral compounds.
- Traeft, Annika,Bogar, Krisztian,Warner, Madeleine,Baeckvall, Jan-E.
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supporting information; experimental part
p. 4807 - 4810
(2009/05/31)
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- Stereo-complementary two-step cascades using a two-enzyme system leading to enantiopure epoxides
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A novel one-pot, two-step, two-enzyme cascade is described. Pro-chiral α-chloro ketones are stereoselectively reduced to the corresponding halohydrins as an intermediate by a biocatalytic hydrogen transfer process. The intermediate is transformed to the corresponding epoxide by a non-enantioselective halohydrin dehalogenase. Thus, by combining a Prelog- or anti-Prelog alcohol dehydrogenase with a non-selective halohydrin dehalogenase, enantiopure (R)- as well as (S)-epoxides were obtained.
- Seisser, Birgit,Lavandera, Ivan,Faber, Kurt,Spelberg, Jeffrey H. Lutje,Kroutil, Wolfgang
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p. 1399 - 1404
(2008/03/28)
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- Continuous enantioselective kinetic resolution of terminal epoxides using immobilized chiral cobalt-salen complexes
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Jacobsen's cobalt-salen complex was covalently immobilized on polymer carriers that are part of different technical setups (polymer powder, composite Raschig rings, PASSflow microreactors) and employed for the enantioselective ring opening of terminal epoxides with water and phenols. The polymer-supported catalysts showed good activity and stereoselectivity and could be used repeatedly after a simple reactivation protocol in both batch as well as continuous-flow modes. Georg Thieme Verlag Stuttgart.
- Solodenko, Wladimir,Jas, Gerhard,Kunz, Ulrich,Kirschning, Andreas
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p. 583 - 589
(2007/12/25)
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- Biocatalytic deuterium- and hydrogen-transfer using over-expressed ADH-'A': Enhanced stereoselectivity and 2H-labeled chiral alcohols
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Employing the over-expressed highly organic solvent tolerant alcohol dehydrogenase ADH-'A' from Rhodococcus ruber DSM 44541, versatile building blocks, which were not accessible by the wild type catalyst, were obtained in > 99% e.e.; furthermore, employing d8-2-propanol as deuterium source, stereoselective biocatalytic deuterium transfer was made feasible to furnish enantiopure deuterium labeled sec-alcohols on a preparative scale employing a single enzyme. The Royal Society of Chemistry 2006.
- Edegger, Klaus,Gruber, Christian C.,Poessl, Tina M.,Wallner, Sabine R.,Lavandera, Ivan,Faber, Kurt,Niehaus, Frank,Eck, Juergen,Oehrlein, Reinhold,Hafner, Andreas,Kroutil, Wolfgang
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p. 2402 - 2404
(2008/03/28)
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- Non-racemic halohydrins via biocatalytic hydrogen-transfer reduction of halo-ketones and one-pot cascade reaction to enantiopure epoxides
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Biocatalytic hydrogen-transfer reduction of α-chloro-ketones furnished non-racemic chlorohydrins by employing either Rhodococcus ruber as lyophilized cell catalyst or an alcohol dehydrogenase preparation from Pseudomonas fluorescens DSM 50106 (PF-ADH). Fo
- Poessl, Tina M.,Kosjek, Birgit,Ellmer, Ursula,Gruber, Christian C.,Edegger, Klaus,Faber, Kurt,Hildebrandt, Petra,Bornscheuer, Uwe T.,Kroutil, Wolfgang
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p. 1827 - 1834
(2007/10/03)
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- Immobilization does not influence the enantioselectivity of CAL-B catalyzed kinetic resolution of secondary alcohols
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Decreasing enantioselectivity (E-value) by increasing conversion has been observed in transesterification reactions of secondary alcohols catalyzed by a pure protein formulation of lipase B from Candida antarctica (Novozym 525 F). Addition of a range of e
- Jacobsen, Elisabeth Egholm,Andresen, Liv Siri,Anthonsen, Thorleif
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p. 847 - 850
(2007/10/03)
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- Aminocyclopentadienyl Ruthenium Complexes as Racemization Catalysts for Dynamic Kinetic Resolution of Secondary Alcohols at Ambient Temperature
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Aminocyclopentadienyl ruthenium complexes, which can be used as room-temperature racemization catalysts with lipases in the dynamic kinetic resolution (DKR) of secondary alcohols, were synthesized from cyclopenta-2,4-dienimines, Ru3(CO)12, and CHCl 3: [2,3,4,5-Ph4(η5-C 4CNHR)]Ru-(CO)2Cl (4: R = i-Pr; 5: R = n-Pr; 6: R = t-Bu), [2,5-Me2-3,4-Ph2(η5-C 4CNHR)]Ru(CO)2Cl (7: R = i-Pr; 8: R = Ph), and [2,3,4,5-Ph4(η5-C4CNHAr)]Ru(CO) 2Cl (9: Ar =p-NO2C6H4; 10: Ar = p-ClC6H4; 11: Ar = Ph; 12: Ar = p-OMeC6H 4; 13: Ar = p-NMe2C6H4). The tests in the racemization of (S)-4-phenyl-2-butanol showed that 7 is the most active catalyst, although the difference decreased in the DKR. Complex 4 was used in the DKR of various alcohols; at room temperature, not only simple alcohols but also functionalized ones such as allylic alcohols, alkynyl alcohols, diols, hydroxyl esters, and chlorohydrins were successfully transformed to chiral acetates. In mechanistic studies for the catalytic racemization, ruthenium hydride 14 appeared to be a key species. It was the major organometallic species in the racemization of (S)-1-phenylethanol with 4 and potassium tert-butoxide. In a separate experiment, (S)-1-phenylethanol was racemized catalytically by 14 in the presence of acetophenone.
- Choi, Jun Ho,Choi, Yoon Kyung,Kim, Yu Hwan,Park, Eun Sil,Kim, Eun Jung,Kim, Mahn-Joo,Park, Jaiwook
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p. 1972 - 1977
(2007/10/03)
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- Process for preparation of optically active halogeno hydroxypropyl compound and glycidyl compound
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A process for preparing regioselectively an optically active 1-halogeno-2-hydroxypropyl compound of the following formula; wherein X is halogen atom and Nu is a heteroatom having a substituent, and an optically active glycidyl compound of the formula; which comprises reacting an optically active epihalohydrin of the formula; with a neucleophilic agent, in the presence of a metal complex of the formula; wherein n is an integer of 0, 1 or 2, Y1, Y2 and Y3 are hydrogen atom, etc., and Y2 and Y3 may form a ring such as benzene, A is a counterion and M is a metal ion, and further subjecting the compound (4) to reaction with a base to prepare the optically active glycidyl compound (5).
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- Enhanced selectivity in Novozym 435 catalyzed kinetic resolution of secondary alcohols and butanoates caused by the (R)-alcohols
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In esterifications of secondary alcohols catalyzed by immobilized lipase B from Candida antarctica (Novozym 435) the E-values decreased during the reaction. Hydrolysis of the corresponding butanoates showed the opposite effect. When an enantiopure (R)-alc
- Jacobsen, Elisabeth Egholm,Van Hellemond, Erik,Moen, Anders Riise,Vazquez Prado, Lucia Camino,Anthonsen, Thorleif
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p. 8453 - 8455
(2007/10/03)
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- Chemoenzymatic dynamic kinetic resolution of β-halo alcohols. An efficient route to chiral epoxides
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Enzymatic resolution of β-chloro alcohols in combination with ruthenium-catalyzed alcohol isomerization led to a successful dynamic kinetic resolution (conversion up to 99% and ee up to 97%). The efficiency of the DKR is dramatically reduced when β-bromo alcohols are used. The presence of the bromo substituent causes decomposition of the ruthenium catalysts, which triggers the progressive deactivation of the enzyme. The synthetic utility of this procedure has been illustrated by the practical synthesis of different chiral epoxides.
- Pamies, Oscar,Baeckvall, Jan-E.
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p. 9006 - 9010
(2007/10/03)
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- Ionic liquid-coated enzyme for biocatalysis in organic solvent
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Ionic liquid-coated enzyme (ILCE) is described as a useful catalyst for biocatalysis in organic solvent. An ionic liquid, [PPMIM]-[PF6] (1, [PPMIM] = 1-(3′-phenylpropyl)-3-methylimidazolium), which is solid at room temperature and becomes liquid above 53°C, was synthesized in two steps from N-methylimidazole. The coating of enzyme was done by simply mixing commercially available enzyme with 1 in the liquid phase above 53°C and then allowing the mixture to cool. A representative ILCE, prepared with a lipase from Pseudomonas cepacia, showed markedly enhanced enantioselectivity without losing any significant activity.
- Lee, Jae Kwan,Kim, Mahn-Joo
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p. 6845 - 6847
(2007/10/03)
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- Water content influences the selectivity of CALB-catalyzed kinetic resolution of phenoxymethyl-substituted secondary alcohols
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Derivatives of 1-phenoxy-2-alkanols were kinetically resolved by esterification with irreversible and reversible acyl donors using lipase B from Candida antarctica (Novozyme 435) as a catalyst. To optimize the relative rate of reaction (the E-value), esterifications in eight different solvents with different water activities were performed. For 3-bromo-1-phenoxy-2-propanol (1), the E-values in all the solvents were higher when the water activity was increased, while the E-values for 1-phenoxy-2-pentanol (2) and 3-chloro-1-phenoxy-2-propanol (3) decreased by increasing water activity. The water content of the various reaction media with the same water activity was determined. Solvents such as 1,4-dioxane, acetonitrile, and tetrahydrofuran contained much more water than hexane, carbon tetrachloride, cyclohexane, toluene, and benzene. At high-water activity, the high-water content of the former group of solvents resulted in termination of the reaction at low conversion. The reason seemed to be that the acyl donor and possibly also the produced esters were hydrolyzed. This was not the case when the esterification was performed in water-immiscible solvents with the same water activity.
- Jacobsen, Elisabeth Egholm,Anthonsen, Thorleif
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p. 577 - 581
(2007/10/03)
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- Oxidation of olefins by palladium(II): Part 17. An asymmetric chlorohydrin synthesis catalyzed by a bimetallic palladium(II) complex
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Previous studies showed that oxidation of α-olefins with monometallic catalysts containing chiral diphosphines and diamines gave chlorohydrins with poor to good enantioselectivites (28-82% ee). The present studies demonstrate that bimetallic catalysts containing a β-triketone and bridging chiral diphosphine and diamines are excellent catalysts for this reaction giving enantioselectivites considerably higher than the monometallic catalysts. Enantioselectivities were more than 50% for most olefins tested. The highest optical purities were 94% ee for propene and 93% ee for allylphenyl ether. A useful feature of this asymmetric synthesis is the fact it is a net air oxidation.
- El-Qisairi, Arab,Henry, Patrick M.
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- Enzyme Assisted Preparation of Enantiomerically Pure β-Adrenergic Blockers II. Building Blocks of High Optical Purity and their Synthetic Conversion
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Based on previous screening results a series of potential building blocks 2-4 for β-adrenergic blockers were prepared both by enzymatic hydrolysis and acyltransfer and further transformed into the corresponding oxiranes and aminoalcohols of defined absolu
- Ader, Ulrich,Schneider, Manfred P.
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p. 205 - 208
(2007/10/02)
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- Pseudomonas Lipases as Catalysts in Organic Synthesis: Specificity of Lipoprotein Lipase
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Described are the structural features of the substrates accepted by lipoprotein lipase from Pseudomonas aeruginosa which can serve as the rules for interpreting and predicting the specificity of this enzyme.
- Kim, Mahn-Joo,Cho, Hangjin
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p. 1411 - 1413
(2007/10/02)
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- Enzyme Assisted Preparation of Enantiomerically Pure β-Adrenergic Blockers III. Optically Active Chlorohydrin Derivatives and Their Conversion
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Optical active chlorohydrin derivatives 2a-m and 3a-m of both enantiomeric series were prepared via both enzymatic hydrolyses and acyltransfer reactions catalysed by a highly selective lipase from Pseudomonas sp..The resulting building blocks were further transformed into the corresponding β-blockers of high enantiomeric purity.
- Ader, Ulrich,Schneider, Manfred P.
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p. 521 - 524
(2007/10/02)
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