- Organic-inorganic nanocrystal reductase to promote green asymmetric synthesis
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An acetophenone reductase from Geotrichum candidum (GcAPRD) was immobilized by the organic-inorganic nanocrystal method. The GcAPRD nanocrystal presented improved stability and recyclability compared with those of the free GcAPRD. Moreover, the GcAPRD nanocrystal reduced broad kinds of ketones with excellent enantioselectivities to produce beneficial chiral alcohols such as (S)-1-(3′,4′-dichlorophenyl)ethanol with >99% yield and >99% ee. The robust and versatile properties of the GcAPRD nanocrystal demonstrated an approach to promote green asymmetric synthesis and sustainable chemistry. This journal is
- Koesoema, Afifa Ayu,Matsuda, Tomoko,Tsriwong, Kotchakorn
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p. 30953 - 30960
(2020/09/11)
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- Structural basis for a highly (S)-enantioselective reductase towards aliphatic ketones with only one carbon difference between side chain
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Aliphatic ketones, such as 2-butanone and 3-hexanone, with only one carbon difference among side chains adjacent to the carbonyl carbon are difficult to be reduced enantioselectively. In this study, we utilized an acetophenone reductase from Geotrichum candidum NBRC 4597 (GcAPRD) to reduce challenging aliphatic ketones such as 2-butanone (methyl ethyl ketone) and 3-hexanone (ethyl propyl ketone) to their corresponding (S)-alcohols with 94% ee and > 99% ee, respectively. Through crystallographic structure determination, it was suggested that residue Trp288 limit the size of the small binding pocket. Docking simulations imply that Trp288 plays an important role to form a C-H?π interaction for proper orientation of ketones in the pro-S binding pose in order to produce (S)-alcohols. The excellent (S)-enantioselectivity is due to a non-productive pro-R binding pose, consistent with the observation that the (R)-alcohol acts as an inhibitor of (S)-alcohol oxidation.
- Koesoema, Afifa Ayu,Sugiyama, Yosuke,Xu, Zichang,Standley, Daron M.,Senda, Miki,Senda, Toshiya,Matsuda, Tomoko
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p. 9543 - 9553
(2019/09/16)
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- Photostable Helical Polyfurans
-
This report describes the design and synthesis of a new class of polyfurans bearing ester side chains. The macromolecules can be synthesized using catalyst-transfer polycondensation, providing precise control over molecular weight and molecular weight distribution. Such obtained furan ester polymers are significantly more photostable than their alkyl analogues owing to the electron-withdrawing nature of the attached subunit. Most interestingly, they spontaneously fold into a compact π-stacked helix, yielding a complex multilayer cylindrical nanoparticle with a hollow, rigid, conjugated core composed of the polyfuran backbone and a soft, insulating outer layer formed by the ester side chains. The length of polymer side chains dictates the outer diameter of such nanoparticles, which for the hexyl ester groups used in the present study is equal to ~2.3 nm. The inner cavity of the conjugated core is lined with oxygen atoms, which set its effective diameter to 0.4 nm. Furthermore, installation of bulkier, branched chiral ester side chains on the repeat unit yields structures that, upon change of solvent, can reversibly transition between an ordered chiral helical folded and disordered unfolded state.
- Varni, Anthony J.,Fortney, Andria,Baker, Matthew A.,Worch, Joshua C.,Qiu, Yunyan,Yaron, David,Bernhard, Stefan,Noonan, Kevin J. T.,Kowalewski, Tomasz
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supporting information
p. 8858 - 8867
(2019/06/07)
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- Asymmetric Enzymatic Hydration of Unactivated, Aliphatic Alkenes
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The direct enantioselective addition of water to unactivated alkenes could simplify the synthesis of chiral alcohols and solve a long-standing challenge in catalysis. Here we report that an engineered fatty acid hydratase can catalyze the asymmetric hydration of various terminal and internal alkenes. In the presence of a carboxylic acid decoy molecule for activation of the oleate hydratase from E. meningoseptica, asymmetric hydration of unactivated alkenes was achieved with up to 93 % conversion, excellent selectivity (>99 % ee, >95 % regioselectivity), and on a preparative scale.
- Demming, Rebecca M.,Hammer, Stephan C.,Nestl, Bettina M.,Gergel, Sebastian,Fademrecht, Silvia,Pleiss, Jürgen,Hauer, Bernhard
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supporting information
p. 173 - 177
(2018/12/11)
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- Biocatalytic Racemization Employing TeSADH: Substrate Scope and Organic Solvent Compatibility for Dynamic Kinetic Resolution
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Racemization in combination with a kinetic resolution is the base for a dynamic kinetic resolution (DKR). Biocatalytic racemization was successfully performed for a broad scope of sec-alcohols by employing a single alcohol dehydrogenase (ADH) variant from Thermoanaerobacter pseudoethanolicus (formerly T. ethanolicus; TeSADH W110A I86A C295A). The catalyst employed as a lyophilized whole cell preparation or cell free extract, which tolerated various non-water miscible organic solvents under micro-aqueous or two-phase conditions, whereby cyclohexane and n-hexane suited best. Various concepts for combining the enzymatic racemization with an enzymatic kinetic resolution to achieve overall a bis-enzymatic DKR were evaluated. A proof of concept showed a successful DKR with racemization in aqueous phase combined with acylation in the organic phase.
- Pop?oński, Jaros?aw,Reiter, Tamara,Kroutil, Wolfgang
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p. 763 - 768
(2018/02/27)
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- A Straightforward Deracemization of sec-Alcohols Combining Organocatalytic Oxidation and Biocatalytic Reduction
-
An efficient organocatalytic oxidation of racemic secondary alcohols, mediated by sodium hypochlorite (NaOCl) and 2-azaadamantane N-oxyl (AZADO), has been conveniently coupled with a highly stereoselective bioreduction of the intermediate ketone, catalyzed by ketoreductases, in aqueous medium. The potential of this one-pot two-step deracemization process has been proven by a large set of structurally different secondary alcohols. Reactions were carried out up to 100 mm final concentration enabling the preparation of enantiopure alcohols with very high isolated yields (up to 98 %). When the protocol was applied to the stereoisomeric rac/meso mixture of diols, these were obtained with very high enantiomeric excesses and diastereomeric ratios (95 % yield, >99 % ee, >99: 1 dr).
- Liardo, Elisa,Ríos-Lombardía, Nicolás,Morís, Francisco,González-Sabín, Javier,Rebolledo, Francisca
-
supporting information
p. 3031 - 3035
(2018/06/27)
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- Asymmetric Reduction of Prochiral Ketones by Using Self-Sufficient Heterogeneous Biocatalysts Based on NADPH-Dependent Ketoreductases
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The development of cell-free and self-sufficient biocatalytic systems represents an emerging approach to address more complex synthetic schemes under nonphysiological conditions. Herein, we report the development of a self-sufficient heterogeneous biocatalyst for the synthesis of chiral alcohols without the need to add an exogenous cofactor. In this work, an NADPH-dependent ketoreductase was primarily stabilized and further co-immobilized with NADPH to catalyze asymmetric reductions without the addition of an exogenous cofactor. As a result, the immobilized cofactor is accessible, and thus, it is recycled inside the porous structure without diffusing out into the bulk, as demonstrated by single-particle in operando studies. This self-sufficient heterogeneous biocatalyst was used and recycled for the asymmetric reduction of eleven carbonyl compounds in a batch reactor without the addition of exogenous NADPH to achieve the corresponding alcohols in 100 % yield and >99 % ee; this high performance was maintained over five consecutive reaction cycles. Likewise, the self-sufficient heterogeneous biocatalyst was integrated into a plug flow reactor for the continuous synthesis of one model secondary alcohol, which gave rise to a space-time yield of 97–112 g L?1 day?1; additionally, the immobilized cofactor accumulated a total turnover number of 1076 for 120 h. This is one of the few examples of the successful implementation of continuous reactions in aqueous media catalyzed by cell-free and immobilized systems that integrate both enzymes and cofactors into the solid phase.
- Benítez-Mateos, Ana I.,San Sebastian, Eneko,Ríos-Lombardía, Nicolás,Morís, Francisco,González-Sabín, Javier,López-Gallego, Fernando
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p. 16843 - 16852
(2017/11/16)
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- From a Sequential to a Concurrent Reaction in Aqueous Medium: Ruthenium-Catalyzed Allylic Alcohol Isomerization and Asymmetric Bioreduction
-
The ruthenium-catalyzed redox isomerization of allylic alcohols was successfully coupled with the enantioselective enzymatic ketone reduction (mediated by KREDs) in a concurrent process in aqueous medium. The overall transformation, formally the asymmetric reduction of allylic alcohols, took place with excellent conversions and enantioselectivities, under mild reaction conditions, employing commercially and readily available catalytic systems, and without external coenzymes or cofactors. Optimization resulted in a multistep approach and a genuine cascade reaction where the metal catalyst and biocatalyst coexist from the beginning.
- Ríos-Lombardía, Nicolás,Vidal, Cristian,Liardo, Elisa,Morís, Francisco,García-álvarez, Joaquín,González-Sabín, Javier
-
supporting information
p. 8691 - 8695
(2016/07/21)
-
- Dual stereocontrolled alkylation of aldehydes with polystyrene-supported nickel complexes derived from α-amino amides
-
Nickel(ii) complexes derived from α-amino amide ligands anchored to gel-type and monolithic polymers act as efficient catalysts for the enantioselective addition of dialkylzinc reagents to aldehydes. Similar to the analogous homogeneous systems, dual stereocontrol in addition products can be achieved by controlling the stoichiometry of the immobilized nickel complex. Aromatic and aliphatic aldehydes were alkylated in good yields with enantioselectivities comparable to those obtained with the homogeneous analogues. These polymer-supported catalysts offer significant advantages as no metal leaching is observed and they can be easily recovered from the reaction mixture by simple filtration and reused for subsequent experiments with consistent catalytic activity.
- Escorihuela, Jorge,Altava, Beln,Burguete, M. Isabel,Luis, Santiago V.
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p. 14653 - 14662
(2015/02/19)
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- Regio- and stereochemistry of Na-mediated reductive cleavage of alkyl aryl ethers
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We have investigated the regio-and stereochemistry of the reductive dealkoxylation of alkyl aryl ethers. Chiral non-racemic secondary alcohols were converted into the corresponding m-terphenyl or 2-biphenyl ethers either via inversion of configuration under Mitsunobu reaction conditions or with retention of configuration under SNAr conditions. The successive cleavage of the aromatic C-O bond occurred in the presence of a stoichiometric amount of Na metal in dry tetrahydrofuran at rt with retention of configuration, thus highlighting that the overall inversion or retention of configuration for the whole two-step procedure is dictated by the stereochemistry of the first synthetic step.
- Azzena, Ugo,Carraro, Massimo,Meloni, Claudia,Murgia, Irene,Pisano, Luisa,Pittalis, Mario,Luisi, Renzo,Musio, Biagia,Degennaro, Leonardo
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p. 1550 - 1554
(2015/01/09)
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- The synthesis of chiral amino diol tridentate ligands and their enantioselective induction during the addition of diethylzinc to aldehydes
-
A series of C2-symmetric chiral amino diol tridentate ligands 3a-g were prepared from achiral bulky organolithiums, achiral bulky primary amines, and optically active epichlorohydrin (ECH). The prepared C 2-symmetric chiral amino diol tridentate ligands were capable of inducing enantioselectivity in the model reaction of aromatic and aliphatic aldehydes with diethylzinc with an ee of up to 96%. The enantioselectivity can be modulated by adjusting the steric hindrance of the achiral reagents employed in the synthesis of the chiral ligand. The configuration of the addition product depended on the configuration of the amino diol ligands, which can be simply controlled as desired by using the ECH with the desired configuration during the preparation of the ligand.
- Zhang, An-Lin,Yang, Li-Wen,Yang, Nian-Fa,Liu, Yan-Ling
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p. 289 - 297
(2014/04/03)
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- Polymer-supported chiral α-amino amides for the asymmetric addition of diethylzinc to aldehydes: Transforming an inactive homogeneous system into an efficient catalyst
-
A series of polymer-supported α-amino amides derived from natural amino acids have been easily synthesized and fully characterized. Their chiral Zn (II) complexes catalyzed the enantioselective addition of diethylzinc to aldehydes to form chiral secondary alcohols in high yields and enantioselectivities up to 95% were obtained. The results showed that the immobilization of this chiral ligand onto a polymeric matrix transforms the inactive homogeneous system into an efficient catalyst. Moreover, the supported catalyst could be re-used at least five times without any significant loss of catalytic activity.
- Escorihuela, Jorge,González, Laura,Altava, Belén,Burguete, M. Isabel,Luis, Santiago V.
-
-
- Cheap and long-life reusable polymer for asymmetric organozinc catalysis based on camphor-derived hydroxyamides
-
Polystyrene grafted with a chiral zinc-complexing camphor-derived N,N-disubstituted hydroxyamide is proposed as a new type of functional polymer of high reusability for the development of sustainable organozinc-catalyzed asymmetric reactions. The main goal of this new functional polymer is the ease of the hydroxyamide-moiety preparation (cheap chiral ligand obtained straightforwardly from an enantiopure starting material coming from the chiral pool), as well as its chemical robustness when compared with other related zinc-complexing functional groups. The latter allows the polymer to be active after multiple applications, without significant loss of its catalytic activity. This fact is exemplified by the design and preparation of a polymer functionalized with a bis(hydroxyamide) proved previously as active in the homogeneous enantioselective addition of diethylzinc to aldehydes. The result is a cheap functional polymer with a very high reusability (the enantioselectivity and chemical yield are maintained practically constant after 20 applications). Additionally, a methodology for the multicycle use of these functional polymers is presented. Copyright
- De Las Casas Engel, Tomas,Sanchez-Carnerero, Esther M.,Gallardo-Araya, Claudio M.,Jimenez, Florencio Moreno,Maroto, Beatriz Lora,De La Moya Cerero, Santiago,Sokolovskaya, Ekaterina
-
p. 771 - 777,7
(2020/07/30)
-
- 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)
-
- CAMPHOR-DERIVED BETA-AMINO ALCOHOL COMPOUNDS, METHOD FOR MANUFACTURING THE SAME AND ASYMMETRIC ADDITION OF ORGANOZINC TO ALDEHYDES USING THE SAME
-
A novel camphor-derived β-amino alcohol compound is disclosed. The novel camphor-derived β-amino alcohol compound can be used in asymmetric addition of organozinc to aromatic and aliphatic aldehydes, including linear aliphatic ones, thus generating corresponding secondary alcohols in high yields and enantiomeric excess.
- -
-
Page/Page column 8
(2012/01/13)
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- A stereoselective inverting sec -alkylsulfatase for the deracemization of sec -alcohols
-
A metallo-β-lactamase-type alkylsulfatase was found to catalyze the enantioselective hydrolysis of sec-alkylsulfates with strict inversion of configuration. This catalytic event, which does not have an analog in chemocatalysis, yields homochiral (S)-configurated alcohols and nonreacted sulfate esters. The latter could be converted into (S)-sec-alcohols as the sole product in up to >99% ee via a chemoenzymatic deracemization protocol on a preparative scale.
- Schober, Markus,Gadler, Petra,Knaus, Tanja,Kayer, Heidemarie,Birner-Gruenberger, Ruth,Guelly, Christian,MacHeroux, Peter,Wagner, Ulrike,Faber, Kurt
-
supporting information; experimental part
p. 4296 - 4299
(2011/10/08)
-
- Switching of enantioselectivity in the catalytic addition of diethylzinc to aldehydes by regioisomeric chiral 1,3-amino sulfonamide ligands
-
Twenty chiral 1,3-amino sulfonamides of two classes (2a-i and 3a-k) have been prepared from (-)-cis-2-benzamidocyclohexanecarboxylic acid (1) and studied as ligands for catalytic enantioselective addition of Et2Zn to a variety of aromatic and aliphatic aldehydes. The ligands 2 and 3 are regioisomers in which the position of the amine and sulfonamide groups is exchanged. Each class of ligands with the same chirality was shown to afford sec-alcohols with the opposite stereochemistry. Structural surveys revealed that the combination of tertiary amino and p-toluenesufonylamido groups works most effectively for the reaction. Through optimization of the structural and reaction conditions, the best ligands quantitatively provided both enantiomeric secondary alcohols in good to excellent enantioselectivity of up to 94% and 98% ee for (S)- and (R)-enantiomers, respectively.
- Hirose, Takuji,Sugawara, Kazuyuki,Kodama, Koichi
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experimental part
p. 5413 - 5428
(2011/08/05)
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- A systematic study of chiral homoprolinols and their derivatives in the catalysis of enantioselective addition of diethylzinc to aldehydes
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Homoprolinol analogs, a class of optically active γ-amino alcohols, were examined systematically in the enantioselective addition reactions of diethylzinc to aldehydes. By comparison of the results catalyzed by these γ-amino alcohols with those by the β-amino alcohols based on pyrrolidine architecture reported in the literature references, we have observed that the γ-amino alcohols are superior to the corresponding β-amino alcohols when the nitrogen and the oxygen are unsubstituted. Among the homoprolinols we tested, 2b gave the best results (45-88% yields, 44-81% ee) in the addition reactions. To the best of our knowledge, 2b has been noticed as one of the most efficient γ-amino alcohol catalysts based on pyrrolidine framework.
- Liu, Chang-Lu,Wei, Chang-Yong,Wang, Shi-Wen,Peng, Yun-Gui
-
experimental part
p. 921 - 928
(2012/06/17)
-
- First example of hydrolytic kinetic resolution of acrylate of secondary alcohols by lipase Amano AK
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Lipase Amano AK is found to be extremely efficient catalyst for hydrolytic kinetic resolution of acrylates of secondary alcohols in aqueous phosphate buffer at pH 7.0. Both aliphatic and benzylic secondary alcohols show good to excellent E values.
- Bora, Pranjal P.,Bez, Ghanashyam,Anal, Jasha Momo H.
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p. 270 - 275
(2012/07/03)
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- Tuning the regio- and stereoselectivity of C-H activation in n-octanes by cytochrome P450 BM-3 with fluorine substituents: Evidence for interactions between a C-F bond and aromatic π systems
-
We employed the water- soluble cytochrome P450 BM-3 to study the activity and regiospecificity of oxidation of fluorinated n-octanes. Three mutations, A74G, F87V, and L188Q, were introduced into P450 BM-3 to allow the system to undergo n-octane oxidation. In addition, the alanine at residue 328 was replaced with a phenylalanine to introduce an aromatic residue into the hydrophobic pocket to examine whether or not van der Waals interactions between a C-F substituent in the substrate and the polarizable π system of the phenylalanine may be used to steer the positioning of the substrate within the active-site pocket of the enzyme and control the regioselectivity and stereoselectivity of hydroxylation. Interestingly, not only was the regioselectivity controlled when the fluorine substituent was judiciously positioned in the substrate, but the electron input into the iron-heme group became tightly coupled to the formation of product, essentially without abortive side reactions. Remarkable enhancement of the coupling efficiency between electron input and product formation was observed for a range of fluorinated octanes in the enzyme even without the A328F mutation, presumably because of interactions of the C-F substituent with the π system of the porphyrin macrocycle within the active-site pocket. Evidently, tightening the protein domain containing the heme pocket tunes the distribution of accessible enzyme conformations and the associated protein dynamics that activate the iron porphyrin for substrate hydroxylation to allow the reactions mediated by the high-valent FeIV=O to become kinetically more commensurate with electron transfer from the flavin adenine dinucleotide (FAD)/flavin mononucleotide (FMN) reductase. These observations lend compelling evidence to support significant van der Waals interactions between the CF2 group and aromatic π systems within the heme pocket when the fluorinated octane substrate is bound. Activation of F-octanes: Cytochrome P450 BM-3-A74GF87VL188Q (see figure) and the A328F variant regionselectively converted fluorinated C8 alkanes to the corresponding secondary alcohols. The pattern of reactivity, especially the unprecedented regio- and stereoselectivity, observed for 4,4-difluorooctane suggested that specific interactions of the fluorinated substituent with aromatic π systems within the active site could tune the reactivity. Copyright
- Wu, Li-Lan,Yang, Chung-Ling,Lo, Feng-Chun,Chiang, Chih-Hsiang,Chang, Chun-Wei,Ng, Kok Yaoh,Chou, Ho-Hsuan,Hung, Huei-Ying,Chan, Sunney I.,Yu, Steve S.-F.
-
experimental part
p. 4774 - 4787
(2011/11/14)
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- Enantioselective addition of diethylzinc to aldehydes catalyzed by d-glucosamine derivatives: Highly pronounced effect of trifluoromethylsulfonamide
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We present the synthesis of β-hydroxy sulfonamides derived from d-glucosamine and their application as ligands in titanium tetraisopropoxide promoted enantioselective addition of diethylzinc to benzaldehyde and selected aromatic and aliphatic aldehydes. The N-trifluoromethylosulfonamido-d-glucosamine derivative is one of the most active ligands known and only 1 mol% of the ligand is sufficient for efficient catalysis of diethylzinc addition. The reaction is highly enantioselective for some aromatic aldehydes and enantiomeric excess up to 99% was obtained.
- Bauer, Tomasz,Smoliński, S?awomir
-
experimental part
p. 247 - 251
(2010/11/18)
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- Highly enantioselective addition of diethylzinc to aldehydes catalyzed by novel chiral tert-amino alcohols
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A series of novel chiral tert-amino alcohols 4a-h derived from enantiomerically pure phenylalanine were synthesized efficiently and used as chiral ligands in the catalytic enantioselective ethylation of aldehydes with diethylzinc (diethylzinc-to-aldehyde addition). The use of 10 mol % of the amino alcohols led to the corresponding sec-alcohols with excellent enantioselectivities (up to 100% ee) and high yields.
- Zhang, Cong-Hai,Yan, Sheng-Jiao,Pan, Sheng-Qiang,Huang, Rong,Lin, Jun
-
experimental part
p. 869 - 873
(2010/10/04)
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- Asymmetric addition of diethylzinc to aldehydes catalyzed by a camphor-derived β-amino alcohol
-
The asymmetric addition of diethylzinc to aromatic and aliphatic aldehydes, including linear aliphatic ones, catalyzed by 2 mol % of β-amino alcohol (1S, 2R)-7,7-dimethyl-1-morpholin-4-yl-bicyclo[2.2.1]heptan-2-ol 10 gave the corresponding secondary alcohols in high yields and with up to 94% ee at ambient temperature after 15 min.
- Wu, Zhi-Long,Wu, Hsyueh-Liang,Wu, Ping-Yu,Uang, Biing-Jiun
-
experimental part
p. 1556 - 1560
(2009/11/30)
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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
-
experimental part
p. 115 - 118
(2009/05/30)
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- Stereoselective bioreduction of bulky-bulky ketones by a novel ADH from Ralstonia sp.
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(Figure Presented) Ketones with two bulky substituents, named bulky-bulky ketones, as well as less sterically demanding ketones were successfully reduced to the corresponding optically highly enriched alcohols using a novel identified recombinant short-chain alcohol dehydrogenase RasADH from Ralstonia sp. DSM 6428 overexpressed in E. coli.
- Lavandera, Ivan,Kern, Alexander,Ferreira-Silva, Bianca,Glieder, Anton,De Wildeman, Stefaan,Kroutil, Wolfgang
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p. 6003 - 6005
(2008/12/21)
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- Asymmetric anti-Prelog reduction of ketones catalysed by Paracoccus pantotrophus and Comamonas sp. cells via hydrogen transfer
-
A broad range of ketones including methyl-aryl-, methyl-alkyl-, cyclic and sterically hindered ketones were reduced to the corresponding anti-Prelog alcohols with moderate to excellent stereoselectivities by employing lyophilised cells of Paracoccus pantotrophus DSM 11072 and Comamonas sp. DSM 15091 via hydrogen transfer. The reduction equivalents were provided using 2-propanol as a hydride donor. For instance, acetophenone was reduced to the corresponding (R)-enantiomer with >99% ee.
- Lavandera, Ivan,Hoeller, Brigitte,Kern, Alexander,Ellmer, Ursula,Glieder, Anton,de Wildeman, Stefaan,Kroutil, Wolfgang
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p. 1954 - 1958
(2008/12/22)
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- One-way biohydrogen transfer for oxidation of sec-alcohols
-
(Chemical Equation Presented) Quasi-irreversible oxidation of sec-alcohols was achieved via biocatalytic hydrogen transfer reactions using alcohol dehydrogenases employing selected ketones as hydrogen acceptors, which can only be reduced but not oxidized. Thus, only 1 equiv of oxidant was required instead of a large excess. For the oxidation of both isomers of methylcarbinols a single nonstereoselective short-chain dehydrogenase/reductase from Sphingobium yanoikuyae was identified and overexpressed in E. coli.
- Lavandera, Ivan,Kern, Alexander,Resch, Verena,Ferreira-Silva, Bianca,Glieder, Anton,Fabian, Walter M. F.,De Wildeman, Stefaan,Kroutil, Wolfgang
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supporting information; experimental part
p. 2155 - 2158
(2009/05/27)
-
- Enantioselective transfer hydrogenation of aliphatic ketones catalyzed by ruthenium complexes linked to the secondary face of β-cyclodextrin
-
Ruthenium-η-arene complexes attached to the secondary face of β-cyclodextrin catalyze the enantioselective reduction (ee up to 98%) of aliphatic and aromatic ketones in aqueous medium in the presence of sodium formate (HCOONa).
- Schlatter, Alain,Woggon, Wolf-D.
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scheme or table
p. 995 - 1000
(2009/05/30)
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- Chiral ligand 2-(2′-piperidinyl)pyridine: synthesis, resolution and application in asymmetric diethylzinc addition to aldehydes
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Chiral ligand 2-(2′-piperidinyl)pyridine 1 has been synthesized in good overall yield by sequential benzylation, hydrogenation and debenzylation of 2,2′-bipyridine. Its enantiomerically pure enantiomers have been obtained by resolution of 2-(1-benzyl-2-piperidinyl)pyridine 2 with d-tartaric acid (or l-tartaric acid) followed by debenzylation. The absolute configuration was determined by X-ray analysis of the (S)-2 d-tartrate. It was demonstrated that 1 can be used as an effective enantioselective catalyst in the addition of diethylzinc to aldehydes. Optically active secondary alcohols with up to 100% enantiomeric excess were obtained in high yields.
- Cheng, Yan-Qin,Bian, Zheng,Kang, Chuan-Qing,Guo, Hai-Quan,Gao, Lian-Xun
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p. 1572 - 1575
(2008/12/21)
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- Hydroxyalkyl thiazolines, a new class of highly efficient ligands for carbonyl additions
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Hydroxyalkyl thiazoline ligands can easily be obtained in an isonitrile-based multicomponent reaction. These ligands are significantly more stable than the comparable oxazoline ligands, and give excellent enantiomeric excess in carbonyl additions of alkyl- and arylzinc compounds. Georg Thieme Verlag Stuttgart.
- Bauer, Michael,Maurer, Frauke,Hoffmann, Svenja M.,Kazmaier, Uli
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experimental part
p. 3202 - 3207
(2009/06/05)
-
- Enzymatic reduction of ketones in "micro-aqueous" media catalyzed by ADH-A from rhodococcus ruber
-
Mono- and biphasic aqueous-organic solvent systems (50% v v-1) as well as micro-aqueous organic systems (99% v v-1) were successfully employed for the biocatalytic reduction of ketones catalyzed by alcohol dehydrogenase ADH-A from Rhodococcus ruber via hydrogen transfer. A clear correlation between the log P of the organic solvent and the enzyme activity-the higher, the better-was found. The use of organic solvents allowed highly stereoselective enzymatic carbonyl reductions at substrate concentrations close to 2.0 M.
- De Gonzalo, Gonzalo,Lavandera, Ivan,Faber, Kurt,Kroutil, Wolfgang
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p. 2163 - 2166
(2008/02/03)
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- Asymmetric biocatalytic reduction of ketones using hydroxy-functionalised water-miscible ionic liquids as solvents
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Bi- and monophasic ionic liquid (IL)/buffer systems were successfully employed for the biocatalytic reduction of ketones catalysed by the alcohol dehydrogenase ADH-'A' from Rhodococcus ruber via hydrogen transfer. Two different catalyst preparations were employed, namely recombinant ADH-'A' 'immobilised' in Escherichia coli and partially purified ADH-'A'. For biphasic systems conversions were acceptable until 20% v v-1 of IL. In contrast, hydroxy-functionalised 'Tris-like'-ILs were successfully employed in monophasic systems up to 90% v v-1 IL. The use of these solvents allowed highly stereoselective enzymatic carbonyl reductions at substrate concentrations from 1.2 to 1.5 M.
- de Gonzalo, Gonzalo,Lavandera, Ivan,Durchschein, Katharina,Wurm, Dietmar,Faber, Kurt,Kroutil, Wolfgang
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p. 2541 - 2546
(2008/03/14)
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- Highly enantioselective biohydrolysis of sec-alkyl sulfate esters with inversion of configuration catalysed by Pseudomonas spp.
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In search of highly enantioselective microbial sec-alkyl sulfatase activity, a broad screening among bacteria, fungi and Archaea revealed several Ralstonia and Pseudomonas spp. as valuable sources, whereas fungi were completely inactive. In particular, Pseudomonas sp. DSM 6611 was able to hydrolyse the (R) enantiomers of a broad range of rac-sec-alkyl sulfate esters with excellent enantioselectivities (E > 200) to furnish the corresponding inverted (S)-sec-alcohols in high ee's. The substrate range of this organism was remarkably broad and bulky groups were also nicely tolerated. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Gadler, Petra,Faber, Kurt
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p. 5527 - 5530
(2008/09/17)
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- Asymmetric diethylzinc addition and phenyl transfer to aldehydes using chiral cis-cyclopropane-based amino alcohols
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A new series of amino alcohols with a chiral cyclopropane backbone have been developed and used in the catalytic asymmetric diethylzinc addition and phenyl transfer to various types of aldehydes. These cyclopropane-based chiral amino alcohols show high enantioselectivity in the addition of organozincs to aromatic and aliphatic aldehydes. For diethylzinc addition to aromatic and aliphatic aldehydes, up to 97% ee and 93% ee are obtained, respectively. For the phenyl transfer to aromatic aldehydes, the best enantioselectivity was 89% ee.
- Zhong, Jiangchun,Guo, Hongchao,Wang, Mingan,Yin, Mingming,Wang, Min
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p. 734 - 741
(2008/02/01)
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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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- Stereoselective enzymatic synthesis of chiral alcohols with the use of a carbonyl reductase from Candida magnoliae with anti-prelog enantioselectivity
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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)
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- 3,3′-diphosphoryl-1,1′-bi-2-naphthol-Zn(II) complexes as conjugate acid-base catalysts for enantioselective dialkylzinc addition to aldehydes
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A highly enantioselective dialkylzine (R22Zn) addition to a series of aromatic, aliphatic, and heteroaromatic aldehydes (5) was developed based on conjugate Lewis acid-Lewis base catalysis. Bifunctional BINOL ligands bearing phosphine oxides [P(=O)R2] (7), phosphonates [P(=O)(OR)2] (8 and 9), or phosphoramides [P(=O)(NR2) 2] (10) at the 3,3′-positions were prepared by using a phospho-Fries rearrangement as a key step. The coordination of a NaphO-Zn(II)-R2 center as a Lewis acid to a carbonyl group in a substrate and the activation of R22Zn(II) with a phosphoryl group (P=O) as a Lewis base in the 3,3′-diphosphoryl-BINOL- Zn(II) catalyst could promote carbon-carbon bond formation with high enantioselectivities (up to >99% ee). Mechanistic studies were performed by X-ray analyses of a free ligand (7) and a tetranuclear Zn(II) cluster (21), a 31P NMR experiment on Zn(II) complexes, an absence of nonlinear effect between the ligand (7) and Et-adduct of benzaldehyde, and stoichiometric reactions with some chiral or achiral Zn(II) complexes to propose a transition-state assembly including monomeric active intermediates.
- Hatano, Manabu,Miyamoto, Takashi,Ishihara, Kazuaki
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p. 6474 - 6484
(2007/10/03)
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- New chiral Schiff base as a tridentate ligand for catalytic enantioselective addition of diethylzinc to aldehydes
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We have developed new chiral Schiff base catalysts for the enantioselective addition of diethylzinc reagents to aldehydes. The reaction of benzaldehyde with diethylzinc in the presence of 1 mol % of the chiral Schiff base catalyst proceeded to afford 1-phenyl-1-propanol in 96% enantiomeric excess (ee).
- Tanaka, Takanori,Yasuda, Yorinobu,Hayashi, Masahiko
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p. 7091 - 7093
(2007/10/03)
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- Enantioselective dialkylzinc addition to aldehydes catalyzed by chiral Zn(II)-BINOLates bearing phosphonates and phosphoramides in the 3,3′-positions
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Highly enantioselective dialkylzinc addition to a series of aldehydes was developed based on chiral Zn(II)-BINOLate catalysts bearing phosphonates [P(=O)(OR)2] and phosphoramides [P(=O)(NMe2)2] at the 3,3′-positions. The reactions proceeded smoothly and showed reductions in the amounts of both catalysts and dialkylzinc reagents to be loaded. Georg Thieme Verlag Stuttgart.
- Hatano, Manabu,Miyamoto, Takashi,Ishihara, Kazuaki
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p. 1762 - 1764
(2008/02/03)
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- Practical synthesis of (S)-(+)-3-octanol by lipase-catalyzed enantioselective acetylation
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(S)-(+)-3-Octanol (S)-1 was prepared in high enantiomeric excess through catalyzed acetylation of racemic alcohol 1 by using lipase from Candida antarctica (Chirazyme L-2) in the presence of vinyl acetate in toluene at 30°C. The pure (S)-1 was obtained in 73% isolated yield with 62% conversion. Moreover, acetate (R)-2 was converted to (S)-1 via mesylation and followed by hydrolysis using sodium bicarbonate solution in 44% yield. Copyright Taylor & Francis Group, LLC.
- Yuasa, Yoshifumi,Yuasa, Yoko
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p. 1687 - 1693
(2007/10/03)
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- 1,1′-Binaphthyl-2,2′-diyl phosphoroselenoyl chloride as a chiral molecular tool for the preparation of enantiomerically pure alcohols and amines
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Enantiomerically pure phosphoroselenoyl chloride bearing a binaphthyl group was synthesized. This phosphoroselenoyl chloride was used to discriminate and resolve simple secondary alcohols. Stereospecific conversions of diastereomerically pure phosphoroselenoic acid esters, obtained by reaction of the chloride with simple secondary alcohols, to enantiomerically pure alcohols and amines were also achieved. Copyright
- Murai, Toshiaki,Matsuoka, Daichi,Morishita, Ken
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p. 4584 - 4585
(2007/10/03)
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- Preparation of single-enantiomer semiochemicals using 2-methoxy-2-(1- naphthyl)propionic acid and 2-methoxy-2-(9-phenanthryl)propionic acid
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Enantioresolution of 3-octanol, 6-methyl-5-hepten-2-ol (sulcatol), and 1-octen-3-ol was conducted using (S)-(+)-2-methoxy-2-(1-naphthyl)propionic acid (MαNP acid) and (S)-(+)-2-methoxy-2-(9-phenanthryl)propionic acid (M9PP acid). In each case, the diastereomeric esters obtained were readily separated by HPLC. The stereochemistry of the esters could be assigned from their respective 1H NMR analyses. Solvolyses of the esters gave enantiopure alcohols and acids. MαNP and M9PP acids displayed almost equivalent properties in 1H NMR anisotropy. The chiral resolving ability of M9PP acid was slightly superior to that of MαNP acid in HPLC.
- Ichikawa, Akio,Ono, Hiroshi
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p. 2559 - 2568
(2007/10/03)
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- α-Hydroxy carboxylic acids as ligands for enantioselective addition reactions of organoaluminum reagents to aromatic and aliphatic aldehydes
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The first examples of the enantioselective titanium-mediated trialkylaluminum additions to aromatic and aliphatic aldehydes catalyzed by optically active α-hydroxy acids are presented. The reactions proceed with very good yields and in good asymmetric induction. Enantioselectivities up to 92% are obtained depending on the ligand and aldehyde used. A stereochemical model for the reaction is proposed.
- Bauer, Tomasz,Gajewiak, Joanna
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p. 851 - 855
(2007/10/03)
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- A new cysteine-derived ligand as catalyst for the addition of diethylzinc to aldehydes: The importance of a 'free' sulfide site for enantioselectivity
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New chiral sulfides and disulfides were synthesized from readily available and inexpensive cysteine by straightforward methods in order to elucidate the relative importance of the various donor atoms (N, O, S) available in free or alkylated form resulting in covalent or dative bonds to the metal, respectively. Their application in the addition of diethylzinc to aldehydes provides secondary alcohols with up to 99% ee, and S-configuration, when catalytic amounts of disulfide ligands with the ability to form an S-Zn bond were used. In contrast to this, benzyl alcohols with the opposite absolute configuration R could be achieved, albeit with decreased yield and enantioselectivity, by the use of alkylated sulfide ligands.
- Braga, Antonio L.,Alves, Elenilson F.,Silveira, Claudio C.,Zeni, Gilson,Appelt, Helmoz R.,Wessjohann, Ludger A.
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p. 588 - 594
(2007/10/03)
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- Enantioselective addition of organozinc reagents to aldehydes catalyzed by 3,3′-bis(diphenylphosphinoyl)-BINOL
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The enantioselective addition of organozinc reagents to aromatic and aliphatic aldehydes 1 gives secondary alcohols 2 with excellent enantioselectivities in high yields through the catalytic use of (R)-3,3′-bis(diphenylphosphinoyl)-BINOL (3) or (R)-3,3′- bis(diphenylthiophosphinoyl)-BINOL (4) without Ti(IV) complexes. The coordination of the O or S atom of a (thio)phosphinoyl group bearing a BINOL backbone to organozinc reagents can efficiently increase the nucleophilicity of the organozinc reagents.
- Hatano, Manabu,Miyamoto, Takashi,Ishihara, Kazuaki
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p. 1561 - 1568
(2007/10/03)
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- Enantioselective diethylzinc additions to aldehydes catalyzed by chiral relay ligands
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A new pyrazole ligand system incorporating fluxional chirality was found to catalyze the addition of diethylzinc to aldehydes giving rise to the corresponding secondary alcohol products in excellent yields (74-99%) with moderate to high enantioselectivities (46-93%). The size of the fluxional group on the ligand correlated with the level of enantioselectivity of the product.
- Sibi, Mukund P.,Stanley, Levi M.
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p. 3353 - 3356
(2007/10/03)
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- α-Hydroxy carboxylic acids as ligands for enantioselective diethylzinc additions to aromatic and aliphatic aldehydes
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The first examples of the enantioselective titanium-mediated diethylzinc additions to aromatic and aliphatic aldehydes catalyzed by optically active α-hydroxy acids are presented. The reactions proceed with very good yield and good asymmetric induction. Enantioselectivities up to 90% are obtained depending on ligand and aldehyde used. A stereochemical model for the reaction is proposed.
- Bauer, Tomasz,Gajewiak, Joanna
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p. 9163 - 9170
(2007/10/03)
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- Synthesis of (4R,9Z)-9-octadecen-4-olide, the female sex pheromone of Janus integer, and its enantiomer
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Enantiomer separation of (±)-8-fert-butyldiphenylsilyloxy-1-octyn-3- ol was achieved by lipase-mediated asymmetric acetylation. The resolved (R)-alkynol was converted into (4R,9Z)-9-octadecen-4-olide, which was identical with the female sex pheromone of the currant stem girdler (Janus integer). The absolute configuration of the natural pheromone was thus established as R. (4S,9Z)-9-Octadecen-4-olide was also synthesized, and found to be pheromonally inhibitory. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
- Shibata, Chie,Mori, Kenji
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p. 1083 - 1088
(2007/10/03)
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- Biocatalytic oxidative kinetic resolution of sec-alcohols: Stereocontrol through substrate-modification
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Whole lyophilised cells of Rhodococcus ruber DSM 44541 were employed for the oxidative kinetic resolution of sec-alcohols using acetone as hydrogen acceptor. The enantioselectivity of this process could be controlled effectively by introducing C-C multiple bonds into substrates, which were inefficiently recognised, in particular short-chain (ω-1)-alcohols and (ω-2)-analogs. Thus, the enantioselectivities of rac-2-pentanol (E=16.8) and rac-3-octanol (E=13.3) were significantly improved by introducing a C=C bond adjacent to the alcohol moiety to give racemic (E)-pent-3-en-2-ol and 4-(E)-octen-3-ol, which were resolved with excellent selectivities (E >100 and 50, respectively). In addition, it was found that high stereodifferentiation between the E- and Z-configured double bonds occurred, as the corresponding (Z)-isomers were not converted. Similar selectivity-enhancing effects were observed with acetylenic analogs.
- Stampfer, Wolfgang,Kosjek, Birgit,Faber, Kurt,Kroutil, Wolfgang
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p. 275 - 280
(2007/10/03)
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