- Cross-linked crystals of subtilisin: Versatile catalyst for organic synthesis
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Cross-linked enzyme crystals (CLECs) of subtilisin exhibit excellent activity in aqueous and various organic solvents. This catalyst is more stable than the native enzyme in both aqueous and mixed aqueous/organic solutions. Subtilisin-CLEC was shown to be a versatile catalyst. It was used for the syntheses of peptides and peptidomimetics, mild hydrolysis of amino acid and peptide amides, enantio- and regioselective reactions, and transesterifications.
- Wang, Yi-Fong,Yakovlevsky, Kirill,Zhang, Bailing,Margolin, Alexey L.
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- Modular solid-phase synthesis, catalytic application and efficient recycling of supported phosphine-phosphite ligand libraries
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In spite of decades of research in the field of homogeneous asymmetric catalysis the discovery of new high performance catalysts still relies heavily on trial-and-error. There is still a lack of efficient combinatorial methods which enable the synthesis and screening of vast ligand libraries, especially for bidentate phosphorus ligands. Here we present a highly modular solid-phase synthetic approach which provides facile access to libraries of phosphine-phosphite ligands in quantitative yield requiring only minimal work-up. The obtained library of supported phosphine-phosphites was successfully applied in rhodium catalyzed asymmetric hydrogenation obtaining high enantioselectivities up to 98%. Also, these polymer supported ligands could be successfully recycled under batch conditions exhibiting only a small decline of activity and no loss of selectivity.
- Heutz, Frank J. L.,Kamer, Paul C. J.
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- Enantioselective hydrolytic reactions of rice bran lipase (RBL): A first report
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Enantioselectivity has been observed in the hydrolysis of racemic N-acetyl amino acid esters with rice bran lipase (RBL). The enzyme shows selectivity towards the (S)-enantiomer. Products with high enantiomeric excess (e.e. >99%) are obtained depending upon the hydrophobicity of the amino acid as well as that of the leaving group.
- Fadnavis,Jadhav, Vasudev
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- ASYMMETRIC HYDROGENATION OF α-ACYLAMINOACRYLIC ACIDS AND ESTERS WITH AXIALLY DISSYMMETRIC BISAMINOPHOSPHINE-RHODIUM COMPLEXES
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From easily resolved 2,2'-diamino-1,1'-binaphthyl were prepared axially dissymmetric bisphosphine ligands, (R)- and (S)-2,2'-bis(diphenylphosphinamino)-1,1'-binaphthyl; the rhodium-catalyzed asymmetric hydrogenation of α-acylaminoacrylic acids and esters gave the corresponding amino acids of up to 95percent optical purity.
- Miyano, Sotaro,Nawa, Masayoshi,Hashimoto, Harukichi
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- Modified silica-heterogenised catalysts for use in aqueous enantioselective hydrogenations
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Modified mesoporous silicas have been prepared, homogeneous organometallic catalysts incorporated and the resulting heterogeneous systems used as catalysts in aqueous enantioselective hydrogenation reactions. A series of catalysts in which the organometallic species was incorporated during gel synthesis generally gave good conversions but low ee values which were usually less than 25%. Preformed silicas with a narrow range of pore size (26 and 37 ?) and an amorphous silica (average pore size 68 ?) were modified by external surface deactivation and/or derivatization of the internal surface for potential tethering of the catalytic species. In general, excellent conversions (80-100%) but modest enantioselectivities (40-50%) were obtained when using 37 and 68 ? silicas, similar to those values obtained using unmodified silicas. Only low conversions were obtained using the modified 26 ? silicas. Pore volume measurements suggest that this is due to very restricted access to the pores when the tether is present. The results indicate that for aqueous hydrogenation the van der Waals interactions of the catalyst with the porous matrix are sufficiently strong to retain the catalyst, thus allowing for its reuse. No major advantage then appears to be gained by the use of potential internal tethers.
- Jamis, Jim,Anderson, John R.,Dickson, Ron S.,Campi, Eva M.,Jackson, W. Roy
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- Asymmetrische Katalyse III. Synthese, spektroskopische Untersuchungen und katalytische Wirkung eines neuen chiralen Phosphanliganden
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The reduction of 3,4-bis(dimenthylphosphino)maleic anhydride (2) with LiAlH4 yields a new optically-active P-ligand, the chiral γ-lactone 3.The structure of 3 was determined by 1H, 13C and 31P-NMR spectroscopy, and X-ray crystal structure analysis.This ligand is used as co-catalyst with BF4 in the catalytic hydrogenation of α-acetamidocinnamic acid and methyl α-acetamidocinnamate.Optical yields of up to 75percent were obtained with the ester.
- Tillack, Annegret,Michalik, Manfred,Fenske, Dieter,Goesmann, Helmut
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- Chirale Bisphosphane VIII. Die enantioselektive Hydrierung von α-Acetamidozimtsaeure durch kationische Rhodium(I)-Komplexe mit optisch reinen (1S,2S)-Cyclopentan-1,2-diyl-bis(phosphonigsaeurediester)- und (1S,2S)-Cyclopentan-1,2-diyl-bis(phosphonigsaeurediamid)-Liganden1
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Treatment of [(1,5-COD)2Rh]O3SCF3 with optically active P2 ligands of the type (1S,2S)-C5H8(PR2)2 [PR2=P(OMe)2 (3), P(OPh)2 (4), P[OCH(Me)Et-(S)]2 (5), P[2-OC10H6C10H6O-2′-(R)] (6), P(NC4H8O-cyclo)2 (7)] gave cationic rhodium complexes bearing these new ligands, [(1,5-COD)Rh{(PR2)2C5H8-(1S,2S)}]O3SCF3 (Rh-3-7). Use of these as catalysts in the homogeneous enantioselective hydrogenation of α-acetamidocinnamic acid to N-acetylphenylalanine provided optical yields of 75-78% ee for the complexes [(1,5-COD)Rh{[P(OPh)2]2C5H8-(1S,2S)} ]O3SCF3 (Rh-4) and [(1,5-COD)Rh{(P[OCH(Me)Et-(S)]2)2C5H8-(1S,2S)}]O3SCF3 (Rh-5), respectively.
- Dahlenburg, Lutz,Eckert, Christine
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- A novel tea-bag methodology for enzymatic resolutions of α-amino acid derivatives in reverse micellar media
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A novel tea bag methodology for resolution of methyl esters of N-acetyl- α-amino acids in reverse micellar medium of bis(2-ethylhexyl) sulfosuccinate sodium salt (AOT) in isooctane-chloroform using immobilized enzymes or microbial cells is presented. The methodology effectively solves the problems of substrate solubility, product separation and surfactant recycling and provides products in high yields (80 to 90%) and excellent optical purities (% ee 97 to >99%).
- Bhalerao,Rao,Fadnavis
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- Facile preparation of an enzyme-immobilized microreactor using a cross-linking enzyme membrane on a microchannel surface
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The enzyme microreactor has considerable potential for use in biotechnological syntheses and analytical studies. Simplifying the procedure of enzyme immobilization in a microreactor is attractive, and it is achievable by utilizing enzyme immobilization techniques and taking advantage of the characteristics of microfluidics. We previously developed a facile and inexpensive preparation method for an enzyme-immobilized microreactor. The immobilization of enzymes can be achieved by the formation of an enzyme-polymeric membrane on the inner wall of the microchannel through cross-linking polymerization in a laminar flow. However, this method is unsuitable for use in conjunction with electronegative enzymes. Therefore, a novel preparation method using poly-L-lysine [poly(Lys)] as a booster and an adjunct for the effective polymerization of electro-negative enzymes was developed in this study. Using aminoacylase as a model for an electronegative enzyme, the reaction conditions for the enzyme-cross-linked aggregation were optimized. On the basis of the determined conditions, an acylase-immobilized tubing microreactor was successfully prepared by cross-linking polymerization in a concentric laminar flow. The resulting microreactor showed a higher stability against heat and organic solvents compared to those of the free enzyme. The developed method using poly(Lys) was applicable to various enzymes with low isoelectric points, suggesting that this microreactor preparation utilizing a cross-linked enzyme in a laminar flow could be expanded to microreactors in which a broad range of functional proteins are employed.
- Honda, Takeshi,Miyazaki, Masaya,Nakamura, Hiroyuki,Maeda, Hideaki
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- P-chirogenic diphosphazanes with axially chiral substituents and their use in rh-catalyzed asymmetric hydrogenation
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A convenient synthesis of enantiopure P-chirogenic diphosphazanes incorporating bulky bisphenol and 1,1′-bi-2-naphtholderived substituents via the functionalization of a readily accessible enantiopure lithium phosphinoamide with chlorophosphoridites was developed. Since the product requires no subsequent deprotection, the protocol provides an easy, convenient synthesis of P-chirogenic ligands on the gram scale. The ligands were applied in the Rh-catalyzed asymmetric hydrogenation of benchmark substrates furnishing enantiomeric excess values up to 96%.
- Moritz, Jan-Ole,Chakrabortty, Soumyadeep,Bernd H. Mu.ller,Spannenberg, Anke,Kamer, Paul C. J.
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- Synthesis of bis(phosphane) palladium and rhodium complexes on a polyethylene oxide grafted polystyrene matrix (tentagel) and the catalytic behavior of the rhodium
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A new polymer-attached rhodium catalyst on a polyethylene oxide-grafted styrene matrix (TentaGel) is described. The corresponding anchor molecules were prepared by starting from different Boc-protected chiral pyrrolidinebisfphosphane)Pd complexes. The cry
- Nagel, Ulrich,Leipold, Joachim
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- Correlation of X-Ray Crystal Structures of Chiral Bisphosphine-Rhodium Catalysts and the Absolute Configuration of the Products Resulted by Their Asymmetric Hydrogenations
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The chiral positioning array (P/M-chirality) of four phenyl rings in the rhodium-chiral bisphosphine catalyst has been revealed to play an important tole in determining the absolute configuration of the asymmetric hydrogenation product.
- Sakuraba, S.,Morimoto, T.,Achiwa, K.
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- A versatile modular approach to new chiral C2-symmetrical ferrocenyl ligands: Highly enantioselective Rh-catalyzed hydrogenation of α- acetamidoacrylic acid derivatives
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An easy, efficient, flexible modular synthesis of a new family of chiral C2-symmetrical ferrocenyl diphosphines (FERRIPHOS) is described. These new ligands gave high enantioselectivities (up to 99.4% ee) in the rhodium- catalyzed hydrogenation of different enamide derivatives.
- Almena Perea, Juan J.,Boerner, Armin,Knochel, Paul
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- Immobilization of rhodium complexes with chiral cationic water soluble ligands on Nafion-H and other strongly acidic cation exchange resins
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Rhodium complexes of the chiral cationic water soluble ligands, pentane>4+, pentane>4+ and (S,S)-2,4-bis-bis)-p
- Toth, Imre,Hanson, Brian E.,Davis, Mark E.
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- Asymmetric transfer hydrogenation of acrylic acids catalyzed by rhodium(I) complexes of diphosphine ligands
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A number of chiral 1,2 1,3 and 1,4-diphosphines have been investigated as ligands for the rhodium catalyzed hydrogen transfer from formic acid and its salts to acrylic substrates. The results reveal a strong dependence of the activity and selectivity of t
- Rocha Gonsalves,Bayon,Pereira,Serra,Pereira
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- Enantioselective hydrogenation in the presence of the rhodium(I) complex with (+)-4S,5S-N4,N4,N5,N5,2,2-hexamethyl -1,3-dioxolane-4,5-dimethaneamine
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Hydrogenation of α-acetamidocinnamic and itaconic acids and their esters was carried out in the presence of the cationic Rh1 triflate complex with (+)-4S,5S-N4,N4,N5,N5,2,2-hexamethyl -1,3-dioxolane-4,5-dimethaneamine (DIODMA). The optical yields depended on the nature of the solvent and the hydrogen pressure and reached 30%. The catalytically active forms of the complexes and their transformations in the presence of phosphines, molecular hydrogen, and the substrate were studied by 1H and 31P NMR spectroscopy.
- Nindakova,Shainyan,Albanov
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- Novel Chiral Water Soluble Phosphines II. Application in Catalytic Asymmetric Hydrogenation
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The results of the homogeneous asymmetric hydrogenation of several dehydroamino acids by rhodium-diene complexes of the chiral ligands; 2,3-O-isopropylidene-2,3-dihydroxy-1,4-bis(bis(p-N,N-dimethylaminophenyl)phosphino)butane, 2a; 2,4-bis(bis(p-N,N-dimethylaminophenyl)phosphino)pentane, 3a; 2,3-bis(bis(p-N,N-dimethylaminophenyl)phosphino)butane, 4a; and their N-protonated and N-Me quaternized analogues are reported.The ligands comprise a versatile set which can be used both in organic and aqueous solvents.A detailed investigation of solvent and substituent effects isprovided.The presence of p-NMe2 groups enhances the rate of reaction in all cases.For the DIOP derivative, 2a, the presence of the dimethylamino group causes a reversal in the observed dominant product antipode.This is attributed predominantly to a change in preferred ligand conformation rather than to a kinetic difference between the two diastereomers of a single ligand conformation.
- Toth, Imre,Hanson, Brian E.,Davis, Mark E.
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- Ruthenium (II)-sulfonated BINAP: A novel water-soluble asymmetric hydrogenation catalyst
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Ruthenium (II)-sulfonated-BINAP has been synthesized and this novel water-soluble complex is shown to be an excellent asymmetric hydrogenation catalyst for 2-acylamino acid precursors and methylenesuccinic acid in both methanolic as well as in neat water solvent systems. Enantiomeric excesses approaching 90% have been obtained in aqueous and methanolic solvents. Effects of solvent, pressure and the addition of organic base on enantioselectivity are described.
- Wan,Davis
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- Enantiopure 1,2-Bis(tert-butylmethylphosphino)benzene as a highly efficient ligand in rhodium-catalyzed asymmetric hydrogenation
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Figure Presented. An electron-rich P-stereogenic bisphosphine ligand named "BenzP" was conveniently prepared from o-dibromobenzene and enantiopure tert-butylmethylphosphine-borane. Its rhodium complex exhibited excellent enantioselectivities of up to 99.9% and high catalytic activity of up to 10000 h-1 TOF in asymmetric hydrogenations of various functionalized alkenes.
- Tamura, Ken,Sugiya, Masashi,Yoshida, Kazuhiro,Yanagisawa, Akira,Imamoto, Tsuneo
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- Synthesis of Novel Chiral Ruthenium Complexes of 2,2'-Bis(diphenylphosphino)-1,1'-binaphthyl and their Use sa Asymmetric Catalysts
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Reactions of n (COD = cyclo-octa-1,5-diene) with the chiral bidentate phosphine ligands 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl, BINAP, and 2,2'bis(di-p-tolylphosphino)-1,1'binaphthyl, p-tolyl-BINAP, give new chiral ruthenium(II) complexes, Ru2Cl4(BINAP)2(NEt3) and Ru2Cl4(p-tolyl-BINAP)2(NEt3) respectively, which serve as excellent catalysts for asymmetric hydrogenation of alkenes and some cyclic anhydrides.
- Ikariya, Takao,Ishii, Youichi,Kawano, Hiroyuki,Arai, Tsuneta,Saburi, Masahiko,et al.
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- Rh-catalyzed asymmetric hydrogenation by using a new family of C2-symmetric bisphosphinites and a bisaminophosphine as ligands
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The application of a new family of four-chiral-centered C2-symmetric bisphosphinites (1, 2 and 3) and the bisaminophosphine 4 in Rh-catalyzed asymmetric hydrogenation of dehydroamino acids has been examined. Up to 98% ee was obtained in the hydrogenation of α-acetamidocinnamic acid, which is comparable with the enantioselection obtained from the best chiral bisphosphinites and bisaminophosphines.
- Zhang, Ao,Jiang, Biao
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- Ionic liquid-phase asymmetric catalytic hydrogenation: Hydrogen concentration effects on enantioselectivity
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Molecular hydrogen is almost four times more soluble in the ionic liquid 1-n-butyl-3-methylimidazolium tetrafluoroborate (BMI·BF4) than in its hexafluorophosphate (BMI·PF6) analogue at the same pressure. The Henry coefficient solubility constant for the solution BMI·BF4/H2 is K = 3.0 × 10-3 mol L-1 atm-1 and 8.8 × 10-4 mol L-1 atm-1 for BMI·PF6/H2, at room temperature. The asymmetric hydrogenation of (Z)-α-acetamido cinnamic acid and kinetic resolution of (±)-methyl-3-hydroxy-2-methylenebutanoate by (-)-1,2-bis((2R,5R)-2,5-diethylphospholano)benzene(cyclooctadiene)rhodium(I) trifluoromethanesulfonate and ichloro[(S)-(-)-2,2′-bis(di-p-tolylphosphino)-1,1′- binaphthyl]ruthenium(II) complexes immobilised in BMI·PF6 and BMI·BF4 were investigated. Remarkable effects in the conversion and enantioselectivity of these reactions were observed as a function of molecular hydrogen concentration in the ionic phase rather than pressure in the gas phase.
- Berger, Alexsandro,De Souza, Roberto F.,Delgado, Marcelo R.,Dupont, Jairton
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- Asymmetric Hydrogenation with Chiral Aminophosphine-Rhodium Complexes and Chiral Recognition by Bisphosphine-Rhodium Complexes in the Asymmetric Hydrogenation of Olefins through the Chiral Helical Conformation of Phenyl Groups on the Phosphorus Atom
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The asymmetric hydrogenation of α-acylaminocinnamic acids with the rhodium complex of (1R,2R)-1,2-bis(N-diphenylphosphino-N-methylamino)cyclohexane has been reported to give preferentially (S)-amino acids.On the contrary, it has been found that the enanti
- Onuma, Ken-ichi,Ito, Tomiyasu,Nakamura, Asao
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- Application of chiral mixed phosphorus/sulfur ligands to enantioselective rhodium-catalyzed dehydroamino acid hydrogenation and ketone hydrosilylation processes
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Chiral mixed phosphorus/sulfur ligands 1-3 have been shown to be effective in enantioselective Rh-catalyzed dehydroamino acid hydrogenation and ketone hydrosilylation reactions (eqs 1, 2). After assaying the influence of the substituents at sulfur, the substituents on the ligand backbone, the relative stereochemistry within the ligand backbone, and the substituents at phosphorus, ligands 2c (R = 3,5-dimethylphenyl) and 3 were found to be optimal in the Rh-catalyzed hydrogenation of a variety of α-acylaminoacrylates in high enantioselectivity (89-97% ee). A similar optimization of the catalyst for the Rh-catalyzed hydrosilylation of ketones showed that ligand 3 afforded the highest enantioselectivities for a wide variety of aryl alkyl and dialkyl ketones (up to 99% ee). A model for asymmetric induction in the hydrogenation reaction is discussed in the context of existing models, based on the absolute stereochemistry of the products and the X-ray crystal structures of catalyst precursors and intermediates.
- Evans, David A.,Michael, Forrest E.,Tedrow, Jason S.,Campos, Kevin R.
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- Chiral bicyclic O,N-bis(diphenylphosphino)aminoalkanols as ligands for enantioselective metal complex hydrogenation catalysts
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The enantiomers of O,N-bis(diphenylphosphino)-2-exo-hydroxy,3-endo-methylamino-norbornene have been prepared from the corresponding aminoalcohols and Ph2PCl.These compounds have been used as ligand for Rh complexes and tested in asymmetric hydrogenation of α-acetamidocinnamic acid, methyl-α-acetamidocinnamate and acetamodoacrylic acid.Optical yields of up to 90percent were obtained.
- Doebler, Chr.,Kreuzfeld, H.-J.,Pracejus, H.
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- Bidentate Phosphine–Phosphoramidite Ligands of the BettiPhos Family for Rh-Catalyzed Asymmetric Hydrogenation
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Phosphine–phosphoramidites comprising a stereogenic phosphorus atom at the phosphoramidite moiety and a Betti base as chiral backbone have been synthesized. Individual diastereomers have been benchmarked as ligands in the Rh-catalyzed asymmetric hydrogenation of dimethyl itaconate to study the interplay of the different elements of chirality. The privileged diastereomer was applied to Rh-catalyzed asymmetric hydrogenation of several functionalized olefins, leading to high enantioselectivities between 91 and 97 % ee, which confirms the effectiveness of the BettiPhos ligand family in asymmetric catalysis.
- Schmitz, Christian,Holthusen, Katharina,Leitner, Walter,Franciò, Giancarlo
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- Complementary Diastereoselectivity in the Synthesis and Hydrolysis of Acylated Cyclodextrins
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The diastereoselectivity of acylation of β-cyclodextrin with the acid chlorides of Ibuprofen, Flurbiprofen and 2-phenylpropanoic acid is complementary, in absolute and relative terms, to that observed in the hydrolysis of the corresponding cyclodextrin esters.
- Coates, John H.,Easton, Christopher J.,Fryer, Nicholas L.,Lincoln, Stephen F.
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- Chemoenzymatic synthesis of a novel ligand for rhodium-catalysed asymmetric hydrogenation
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The hydrogenation of alkenes 7a-g using a chiral rhodium catalyst 6 (based on a bicyclo[3.2.0]heptane framework) takes place to give the phenylalanine derivatives 8a-g with remarkably high stereoselectivity (59-92% ee).
- Adger, Brian,Berens, Ulrich,Griffiths, Matthew J.,Kelly, Michael J.,McCague, Ray,Miller, John A.,Palmer, Christopher F.,Roberts, Stanley M.,Selke, Ruediger,Vitinius, Ute,Ward, Guy
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- Amphiphilic polymer supports for the asymmetric hydrogenation of amino acid precursors in water
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This paper describes the synthesis and characterization of a new class of amphiphilic, water-soluble diblock copolymers based on 2-oxazoline derivatives with pendent (2S,4S)-4-diphenylphosphino-2-(diphenylphosphinomethyl)pyrrolidine (PPM) units in the hydrophobic block. The synthetic strategy involves the preparation of a diblock copolymer precursor with ester functionalities in the side chain; which were converted into carboxylic acids in a polymer-analogous step and finally reacted with the PPM ligand. The structures of the copolymers were characterized by 1H and 31P NMR spectroscopy and GPC measurements. Subsequently, these polymers were successfully utilized as a polymeric support for the asymmetric hydrogenation of 1) (Z)-α-acetamido cinnamic acid and 2) methyl (Z)-α-acetamido cinnamate in water, showing 90% substrate conversion at 25 °C within 20 minutes at atmospheric H2 pressure (1 bar) for methyl (Z)-α-acetamido cinnamate.
- Zarka, M. Tobias,Nuyken, Oskar,Weberskirch, Ralf
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- Monodentate Phosphoramidites: A Breakthrough in Rhodium-Catalysed Asymmetric Hydrogenation of Olefins
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Monodentate phosphoramidites based on BINOL or substituted BINOL are excellent ligands for the rhodium-catalysed asymmetric hydrogenation of olefins. Very high enantioselectivities were obtained with MonoPhos (7a) the simplest member of this class, a ligand that is prepared in a single step from BINOL and HMPT. Turnover numbers up to 6000 have been obtained in the hydrogenation of dehydroamino acid derivatives. Enantioselectivities in the hydrogenation of dehydroamino acids are solvent dependent; in non-protic solvents they range from 95-99%. Itaconic acid and its dimethyl ester could be hydrogenated with 96 and 94% e.e., respectively. Hydrogenation of aromatic enamides gave the corresponding acylated amines in 86-94% e.e. Several analogous phosphoramidite ligands have been pre-pared. Surprisingly, bidentate ligands gave poorer results, both in terms of rate as well as enantioselectivity. Taddol-based phosphoramidites led to poor e.e. and slow rates. Methyl substituents at the 3,3′-position of BINOL led to a sharply reduced rate and a somewhat lower enantioselectivity. Bromo substituents at the 6,6′-position led to a slightly reduced rate but little effect was seen on enantioselectivity. Use of octahydro-MonoPhos (11) gave results that were very similar to those obtained with 7a. The rate of the reaction is dependent on the hydrogen pressure, however, the enantioselectivity is not affected. The rate of the dehydroamino acid hydrogenation also increases if the ligand to rhodium ratio is reduced from 2.2 to 1.5 or even to 1.0; yet, there is no deleterious effect on the enantioselectivity. Catalytic activity ceases with L/Rh = 3 when dehydroamino acid derivatives were used as substrate. The reaction shows a positive non-linear effect, which confirms the presence of Rh-complexes with more than one ligand. Following the hydrogenation of methyl 2-acetamidocinnnamate with Rh(nbd)2BF4/7a by electrospray mass spectrometry showed the presence of several rhodium species. Notable are the presence of [Rh(7a)]3+ and [Rh(7a)]4+. There is at present insufficient evidence to conclude if the active catalytic species carries one or two ligands. In view of the low cost of MonoPhos this invention might well lead to a broader application of asymmetric olefin hydrogenation for the production of enantiopure amino acids and amines.
- Van Den Berg, Michel,Minnaard, Adriaan J.,Haak, Robert M.,Leeman, Michel,Schudde, Ebe P.,Meetsma, Auke,Feringa, Ben L.,De Vries, André H. M.,Maljaars, C. Elizabeth P.,Willans, Charlotte E.,Hyett, David,Boogers, Jeroen A. F.,Henderickx, Hubertus J. W.,De Vries, Johannes G.
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- Bipnor: A new, efficient bisphosphine having two chiral, nonracemizable, bridgehead phosphorus centers for use in asymmetric catalysis
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Optically active phosphorus ligands are widely used in homogeneous asymmetric catalysis. However, among the numerous available structures of this type, the subclass of optically active bisphosphines with at least one chiral phosphorus atom is rather underdeveloped. A bisphosphine with two chiral, nonracemizable bridgehead phosphorus centers, (meso,d/l)-2,2',3,3'-tetraphenyl-4,4',5,5'-tetramethyl-6,6'-bis-1-phosphanorb orna-2,5-dienyl (BIPNOR), can be obtained by thermolysis of 1,1'-bisphospholyl with diphenylacetylene. Here, we report the resolution of the d/l isomer by means of a chiral palladium complex to give the two optically active forms of BIPNOR. We then investigate the catalytic properties of BIPNOR, incorporated in Rh(I) and Ru(II) catalysts for the hydrogenation of olefins and ketones and in a Pd(II) catalyst for asymmetric alkylation reactions. BIP-NOR is shown to give good results in these catalytic reactions.
- Robin, Frederic,Mercier, Francois,Ricard, Louis,Mathey, Francois,Spagnol, Michel
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- The Asymmetric Homogeneous Hydrogenation of Olefins with the Rhodium Complexes of (1S,2S)-1,2-Bis(diphenylphosphinamino)cyclohexane and (2S,3S)-2,3-Bis(diphenylphoshinamino)butane
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The effect of triethylamine on asymmetric hydrogenation has been studied using the cationic rhodium complex of (1S,2S)-1,2-bis(diphenylphosphinamino)cyclohexane or (2S,3S)-2,3-bis(diphenylphosphinamino)butane as a catalyst.By the addition of triethylamine
- Onuma, Ken-ichi,Ito, Tomiyasu,Nakamura, Asao
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- Synthesis of Binol-based diphosphinites bearing chiral phospholane units and their application in asymmetric catalysis
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New diphosphinite ligands based on atropoisomeric diol backbones and (R,R)-2,5-dimethylphospholane moieties have been prepared and fully characterised. For each ligand structure, both diastereomers have been synthesised. These ligands are available through a straightforward procedure in good yields. The solid state structures of two diastereomeric ligands are reported. These ligands have been applied to Rh-catalysed asymmetric hydrogenations and hydroformylations of CC bonds as well as in Ir-catalysed asymmetric hydrogenations of CN bonds. Turnover frequencies in the range of 10,000 h-1 and enantioselectivities of up to 98% ee have been achieved. The different chirality elements within the ligands led to marked cooperative effect in catalysis. Interestingly, there is no general privileged diastereomeric structure but rather a matched diastereomer for each application.
- Hammerer, Tim,Weisgerber, Laurent,Schenk, Stefan,Stelzer, Othmar,Englert, Ulli,Leitner, Walter,Franci, Giancarlo
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- Enantioselective catalysis 113: New menthylphosphane ligands differing in steric and electronic properties
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A concept for bisphosphane ligands was developed, in which chirality is derived from the optically active (1R,3R,4S)-menthyl substituents in PMen2 groups and the backbone between the phosphorus units is varied (o-phenylene, 2,2'-biphenylene, 1,1'-ferrocenediyl); one of the two PMen2 groups was also replaced by a PPh2 unit. The synthesis and characterisation of seven new menthylphosphanes is described. Emphasis is put on the NMR assignment of the menthyl protons by two-dimensional methods and 13C-1H shift correlation. The ligands have been used in Rh and Ni complexes in several model reactions of enantiosclective catalysis giving optical inductions in the low to middle range.
- Brunner,Janura
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- Highly Enantioselective Pd-Catalyzed Synthesis of P-Stereogenic Supramolecular Phosphines, Self-Assembly, and Implication
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Metal-catalyzed asymmetric addition of a secondary phosphine to an aryl halide is one of the most efficient and reliable approaches for the construction of enantiopure carbon-phosphorus bonds. An isolated Pd(II) complex (5) catalyzes the carbon-phosphorus coupling reaction between tolylphenylphosphine (1a) and 3-iodophenylurea (2b), which proceeds with an unprecedented enantiomeric excess (ee) of 97%. The generality of the strategy has been demonstrated by preparing a small library of a new class of P-stereogenic phosphines with an in-built hydrogen bonding motif for the first time. The P-stereogenic phosphines self-assemble on a metal template via deliberately installed hydrogen-bonding motifs and mimic the bidentate ligand coordination. Interestingly, when it was employed in asymmetric hydrogenation, the supramolecular phosphine {1-(3-(phenyl(o-tolyl)phosphanyl)phenyl)urea} (6b) produced the corresponding hydrogenated product with the highest enantiomeric excess of 99% along with excellent conversion, demonstrating the potential of these enantioenriched P-chirogenic supramolecular phosphines in asymmetric catalysis.
- Koshti, Vijay S.,Mote, Nilesh R.,Gonnade, Rajesh G.,Chikkali, Samir H.
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- Asymmetrische Katalysen LII. Rhodiumkatalysierte enantioselective Transferhydrierung von C=C-Doppelbindungen mit dem System HCO2H/NEt3 als Wasserstoffquelle
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Enantioselective rhodium catalyzed transfer hydrogenation with a mixture of formic acid and triethylamine as hydrogen source was used for the asymmetric hydrogenation of α,β-unsaturated carboxylic acids, esters and ketones, and of olefins.In certain cases
- Brunner, H.,Leitner, W.
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- A novel chiral water-soluble phosphine ligand based on a water-soluble acrylic acid salt
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(2S,4S)-4-diphenylphosphino-2-diphenylphosphinomethylpyrrolidine reacts with poly(acrylic acid) to form a macro-ligand useful in biphasic chiral reductions.
- Malmstroem, Torsten,Andersson, Carlaxel
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Read Online
- Preparation and use of MeO-PEG-supported chiral diphosphine ligands: Soluble polymer-supported catalysts for asymmetric hydrogenation
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Two new chiral MeO-PEG-supported (R)-BINAP and (3R,4R)-Pyrphos ligands were synthesized and employed in the Ru(II)- and Rh(I)-catalyzed asymmetric hydrogenation of 2-(6′-methoxy-2′-naphthyl)propenoic acid 5 and prochiral enamides 10. The results showed that these new soluble polymeric catalysts exhibited high catalytic activity and enantioselectivity. Enantiomeric excesses (e.e.s) in the ranges 90-96% and 86-96% were achieved in the hydrogenation of 5 and 10, respectively. Furthermore, these catalysts could be recovered easily and the recycled catalysts were shown to maintain their efficiency in subsequent reactions.
- Fan, Qing-Hua,Deng, Guo-Jun,Lin, Chi-Ching,Chan, Albert S.C.
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- Modification of (S)-N,N-Dimethyl-1-ethylamine (BPPFA) as a Ligand for Asymmetric Hydrogenation of Olefins Catalyzed by a Chiral Rhodium (I) Complex
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Asymmetric homogeneous hydrogenation of prochiral olefins catalyzed by chiral rhodium (I) complexes was carried out by using several ferrocenylphosphines as ligands which play a key role of the chiral recognition.Modifications of BPPFA were made in order to examine a steric effect of the given substituent at the asymmetric center on the efficiency of the chiral ligands, indicating the parent BPPFA to be superior to the others examined for the asymmetric hydrogenation of highly functionalized olefins.
- Yamamoto, Keiji,Wakatsuki, Junya,Sugimoto, Ryuichi
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- MARKED TEMPERATURE EFFECT ON THE ENANTIOSELECTIVE HYDROLYSIS IN ARTIFICAL MEMBRANES
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The enantioselectivity was markedly elevated at temperatures somewhat higher than the phase transitions for the hydrolysis of hydrophobic amino acid esters (p-nitrophenyl N-dodecanoyl-D(L)-phenylalaninate by a hydrophobic dipeptide (tetradecanoyl-L-histidyl-L-leucine) in the artificial membrane (dialkyldimethylammonium bromides) systems.
- Ueoka, Ryuichi,Matsumoto, Yoko,Nagamatsu, Toshiro,Hirohata, Shoichi
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- Selectivity in Carbonic Anhydrase Catalyzed Hydrolysis of Standard N-Acetyl-DL-amino Acid Methyl Esters
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Carbonic anhydrase-catalyzed hydrolysis of some standard N-acetyl-DL-amino acid methyl esters proceeds with high enantioselectivity.This enzyme hydrolyses selectively D amino acid derivatives in contrast to proteases which have a L stereoselectivity. Key Words: carbonic anhydrase, hydrolysis, N-acetyl-DL-amino acid methyl esters, enantioselectivity.
- Chenevert, Robert,Rhlid, Rachid Bel,Letourneau, Martin,Gagnon, Rene,D'Astous, Linda
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Read Online
- Structure-activity relationship studies of dipeptide-based hepsin inhibitors with Arg bioisosteres
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Hepsin is a type II transmembrane serine protease (TTSP) associated with cell proliferation and overexpressed in several types of cancer including prostate cancer (PCa). Because of its significant role in cancer progression and metastasis, hepsin is an attractive protein as a potential therapeutic and diagnostic biomarker for PCa. Based on the reported Leu-Arg dipeptide-based hepsin inhibitors, we performed structural modification and determined in vitro hepsin- and matriptase-inhibitory activities. Comprehensive structure-activity relationship studies identified that the p-guanidinophenylalanine-based dipeptide analog 22a exhibited a strong hepsin-inhibitory activity (Ki = 50.5 nM) and 22-fold hepsin selectivity over matriptase. Compound 22a could be a prototype molecule for structural optimization of dipeptide-based hepsin inhibitors.
- Kwon, Hongmok,Ha, Hyunsoo,Jeon, Hayoung,Jang, Jaebong,Son, Sang-Hyun,Lee, Kiho,Park, Song-Kyu,Byun, Youngjoo
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supporting information
(2020/12/25)
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- Cobalt-Catalyzed Asymmetric Hydrogenation of α,β-Unsaturated Carboxylic Acids by Homolytic H2 Cleavage
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The asymmetric hydrogenation of α,β-unsaturated carboxylic acids using readily prepared bis(phosphine) cobalt(0) 1,5-cyclooctadiene precatalysts is described. Di-, tri-, and tetra-substituted acrylic acid derivatives with various substitution patterns as well as dehydro-α-amino acid derivatives were hydrogenated with high yields and enantioselectivities, affording chiral carboxylic acids including Naproxen, (S)-Flurbiprofen, and a d-DOPA precursor. Turnover numbers of up to 200 were routinely obtained. Compatibility with common organic functional groups was observed with the reduced cobalt(0) precatalysts, and protic solvents such as methanol and isopropanol were identified as optimal. A series of bis(phosphine) cobalt(II) bis(pivalate) complexes, which bear structural similarity to state-of-the-art ruthenium(II) catalysts, were synthesized, characterized, and proved catalytically competent. X-band EPR experiments revealed bis(phosphine)cobalt(II) bis(carboxylate)s were generated in catalytic reactions and were identified as catalyst resting states. Isolation and characterization of a cobalt(II)-substrate complex from a stoichiometric reaction suggests that alkene insertion into the cobalt hydride occurred in the presence of free carboxylic acid, producing the same alkane enantiomer as that from the catalytic reaction. Deuterium labeling studies established homolytic H2 (or D2) activation by Co(0) and cis addition of H2 (or D2) across alkene double bonds, reminiscent of rhodium(I) catalysts but distinct from ruthenium(II) and nickel(II) carboxylates that operate by heterolytic H2 cleavage pathways.
- Chirik, Paul J.,Shevlin, Michael,Zhong, Hongyu
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supporting information
(2020/03/13)
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- Batch versus flow stereoselective hydrogenation of Α-acetamido-cinnamic acid catalyzed by an Au(I) complex
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A chiral gold (I) (2S,4S)-1-tert-butoxycarbonyl-4-diphenylphosphino-2-(diphenylphosphino- methyl) pyrrolidine (BPPM) complex has been prepared using [Au(SMe2)Cl] as precursor. The heterogenization of the Au-BPPM catalyst onto the CNT support followed two routes, ie (i) the non-covalent immobilization of the gold(I)complex by dry-impregnation, and (b) covalent immobilization of the gold(I)complex on a pre-functionalized CNT. These catalysts afford the stereoselective hydrogenation of α-acetamidocinnamic acid to the (R)-N-acetyl-phenylalanine enantiomer. The nature of the solvent affected both the enantioselectivity and TOFs. Among MeOH, EtOH, and TFE, methanol appeared to be the most efficient one (at 80 °C a TOF of 0.37 h?1 for a total enantioselectivity to the R-isomer). Transferring the reaction in the flow reactor, under similar conditions (methanol, room temperature) led to a 10 time increase of the TOF with no change in the stereoselectivity. The decrease of the TOF in time for both the reference Rh and the Au catalysts was assigned to their partial modification under the reaction conditions. The heterogenization of the Au-BPPM catalyst onto the CNT support, for the same content of Au-complex, led to a very important increase of the conversion with no change in the selectivity. However, the covalent bonding was more efficient affording a very high increase of the conversion even at room temperature (95% after 24 h), thus demonstrating that the anchoring a support increases the dispersion, and in consequence the efficiency. These CNT-Au-BPPM catalysts preserved the catalytic performances during recycling as also confirmed by the characterization results.
- Negoi, Alina,Cojocaru, Bogdan,Parvulescu, Vasile I.,Imlyhen, Nora,Gouygou, Maryse
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- Reversible, short α-peptide assembly for controlled capture and selective release of enantiomers
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Although significant progress has been achieved with short peptide nanostructures, the construction of switchable membrane assemblies remains a great challenge. Here we report short α-peptide assemblies that undergo thermo-reversible switching between assembly and disassembly states, triggered by the conformational change of laterally grafted short peptides from a folded α-helix to a random coil conformation. The α-helical peptide based on two oligoether dendron side groups forms flat disks, while the peptide helix based on three dendron side groups forms hollow vesicles. The vesicular membrane can spontaneously capture a racemic mixture through the self-formation of vesicular containers upon heating and enantioselectively release the chiral guest molecule through preferential diffusion across the vesicular walls.
- Chen, Xi,He, Ying,Kim, Yongju,Lee, Myongsoo
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p. 5773 - 5776
(2016/06/09)
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- Solid-phase synthesis of recyclable diphosphine ligands
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An efficient solid-phase synthetic approach towards diphosphine ligands is demonstrated. This modular method offers facile access to this important class of ligands, in quantitative yield, providing huge potential for ligand fine-tuning. These supported ligands can be efficiently applied in asymmetric catalysis. Moreover, the immobilized catalysts can successfully be recycled multiple times addressing several synthetic and work-up challenges in the field of catalytic chemistry.
- Heutz, Frank J.L.,Samuels, Michiel C.,Kamer, Paul C.J.
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p. 3296 - 3301
(2015/06/08)
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- Synthesis of tertiary and quaternary amine derivatives from wood resin as chiral NMR solvating agents
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Chiral tertiary and quaternary amine solvating agents for NMR spectroscopy were synthesized from the wood resin derivative (+)-dehydroabietylamine (2). The resolution of enantiomers of model compounds [Mosher's acid (3) and its n-Bu4N salt (4)] (guests) by (+)-dehydroabietyl-N,N-dimethylmethanamine (5) and its ten different ammonium salts (hosts) was studied. The best results with 3 were obtained using 5 while with 4 the best enantiomeric resolution was obtained using (+)-dehydroabietyl-N,N-dimethylmethanaminium bis(trifluoromethane-sulfonimide) (6). The compounds 5 and 6 showed a 1:1 complexation behaviour between the host and guest. The capability of 5 and 6 to recognize the enantiomers of various α-substituted carboxylic acids and their n-Bu4N salts in enantiomeric excess (ee) determinations was demonstrated. A modification of the RES-TOCSY NMR pulse sequence is described, allowing the enhancement of enantiomeric discrimination when the resolution of multiplets is insufficient.
- Laaksonen, Tiina,Heikkinen, Sami,W?h?l?, Kristiina
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supporting information
p. 20873 - 20886
(2015/12/23)
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- RHODIUM CATALYST AND METHOD FOR MANUFACTURING OPTICALLY ACTIVE COMPOUND USING THE SAME
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PROBLEM TO BE SOLVED: To provide a new rhodium complex stable in the air, easy in handling and using an inexpensive optically active H-phosphinate HP(O)R(OR') as a ligand, and a method for asymmetrically hydrogenating olefins efficiently using the same. SOLUTION: The rhodium complex compound has a structure represented by the following general formula (I). (Where in the formula (I), R1 and R2 are carbon substituents which may be the same or different, and two olefins coordinated in Rh may combine with each other as shown by a dotted line to form a ring structure.) COPYRIGHT: (C)2015,JPOandINPIT
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Paragraph 0024; 0025; 0026
(2017/01/05)
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- Efficient asymmetric hydrogenation of α-acetamidocinnamates through a simple, readily available monodentate chiral H-phosphinate
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An air-stable, simple (RP)-mentylbenzylphosphinate, readily available in large quantities, can efficiently induce the rhodium-catalyzed asymmetric hydrogenation of α-acetamidocinnamates with high enantioselectivity (up to 99.6 % ee). Intramolecular hydrogen bonding plays an important role in this asymmetric induction.
- Wang, Xiang-Bo,Goto, Midori,Han, Li-Biao
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supporting information
p. 3631 - 3635
(2014/04/03)
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- Synthesis and reactivity of chiral, wide-bite-angle, hybrid diphosphorus ligands
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Effective and modular synthetic approaches toward phosphine-phosphite ligands and phosphine-phosphonite ligands featuring a diphenyl ether backbone have been developed. The phosphine-phosphite ligands are obtained by a two-step protocol from 2-bromo-2′-methoxydiphenyl ether. The phosphine-phosphonite ligands are prepared in a four-step synthetic protocol that involves a novel, unsymmetrical diphenyl ether derived phosphine-phosphorusdiamide as key building block. Structural studies on PtII complexes with either phosphine-phosphite or phosphine-phosphonite ligands indicate strict cis coordination for these ligand systems. High-pressure NMR spectroscopy studies of Rh complexes under syngas indicate the presence of two ea isomers for Rh(H)(CO)2(PP). The existence of this mixture is further supported by high-pressure IR spectroscopy studies. In order to benchmark the activity and selectivity of these novel, wide-bite-angle, mixed-donor ligands, they were screened in Pd-catalyzed asymmetric allylic alkylation as well as Rh-catalyzed hydrogenation and hydroformylation reactions. The ligands give 100-% conversion and low-to-moderate enantioselectivity in the allylic alkylation of 1,3-diphenyl-2-propenyl acetate and cyclohexyl-2-enyl acetate with dimethyl malonate. In the hydroformylation of styrene, good conversion and regioselectivities are achieved but only moderate enantioselectivity. The ligands give good conversions in asymmetric hydrogenation of typical substrates, with good-to-excellent enantioselectivities of up to 97-% depending on the substrate. The design of two subclasses of chiral, mixed-donor diphosphorus ligands with a diphenylether backbone is described. Both phosphine-phosphonite and phosphine-phosphite derivatives are accessible. Coordination to PtII and RhI is described, and high-pressure spectroscopy under syngas provides information on coordination geometry. The chiral ligand systems are benchmarked in Pd-catalyzed allylic alkylation and Rh-catalyzed hydrogenation and hydroformylation.
- Czauderna, Christine Fee,Cordes, David B.,Slawin, Alexandra M. Z.,Müller, Christian,Van Der Vlugt, Jarl Ivar,Vogt, Dieter,Kamer, Paul C. J.
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p. 1797 - 1810
(2015/04/27)
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- Synthesis and Reactivity of Chiral, Wide-Bite-Angle, Hybrid Diphosphorus Ligands
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Effective and modular synthetic approaches toward phosphine-phosphite ligands and phosphine-phosphonite ligands featuring a diphenyl ether backbone have been developed. The phosphine-phosphite ligands are obtained by a two-step protocol from 2-bromo-2′-methoxydiphenyl ether. The phosphine-phosphonite ligands are prepared in a four-step synthetic protocol that involves a novel, unsymmetrical diphenyl ether derived phosphine-phosphorusdiamide as key building block. Structural studies on PtII complexes with either phosphine-phosphite or phosphine-phosphonite ligands indicate strict cis coordination for these ligand systems. High-pressure NMR spectroscopy studies of Rh complexes under syngas indicate the presence of two ea isomers for Rh(H)(CO)2(PP). The existence of this mixture is further supported by high-pressure IR spectroscopy studies. In order to benchmark the activity and selectivity of these novel, wide-bite-angle, mixed-donor ligands, they were screened in Pd-catalyzed asymmetric allylic alkylation as well as Rh-catalyzed hydrogenation and hydroformylation reactions. The ligands give 100-% conversion and low-to-moderate enantioselectivity in the allylic alkylation of 1,3-diphenyl-2-propenyl acetate and cyclohexyl-2-enyl acetate with dimethyl malonate. In the hydroformylation of styrene, good conversion and regioselectivities are achieved but only moderate enantioselectivity. The ligands give good conversions in asymmetric hydrogenation of typical substrates, with good-to-excellent enantioselectivities of up to 97-% depending on the substrate. Copyright
- Czauderna, Christine Fee,Cordes, David B.,Slawin, Alexandra M. Z.,Müller, Christian,Van Der Vlugt, Jarl Ivar,Vogt, Dieter,Kamer, Paul C. J.
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p. 1797 - 1810
(2014/04/17)
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- DEVICE AND METHOD FOR EVALUATING ORGANIC MATERIAL FOR ORGANIC SOLAR CELL
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Provided are a novel 1,2-bis(dialkylphosphino)-4,5-(methylenedioxy)benzene derivative that forms a metal complex having particularly high asymmetry induction capacity and catalytic activity on β-dehydroamino acids, a method for manufacturing the same, a metal complex having this 1,2-bis(dialkylphosphino)-4,5-(methylenedioxy)benzene derivative as a ligand, and an asymmetric hydrogenation method using this metal complex. A 1,2-bis(dialkylphosphino)-4,5-(methylenedioxy)benzene derivative represented by general formula (1). (In the formula, R1 and R2 represent an alkyl group having 1-10 carbon atoms, and R1 and R2 have different numbers of carbon atoms.)
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Paragraph 0082; 0083; 0084; 0085; 0086
(2014/08/07)
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- Pd and Ru complexes bearing axially chiral ligands for the asymmetric hydrogenation of C=C and C=O double bonds
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Complexes composed of either Pd or Ru as central metal and ligands with axial chirality in all cases were used as hydrogenation catalysts. The ligands were (R)- and (S)-6,6′-dimethyl-2,2′-diaminobiphenyl, (R)-(+)-1-1′-Bi(2-naphtylamine), (R)-2,2′-Bis(diphenylphosphino)-1, 1′-binaphthalene and (R)-2,2′-Bis(di-p-tolylphosphino)-1,1′- binaphthyl. The Pd(II) complexes had one diamine ligand and the Ru(II) complexes had one bisphosphine and one diamine ligand, forming seven member chelate rings with the metal center. The pro-chiral substrates used were itaconic acid, α-acetamidocinnamic acid and acetophenone. The Pd complexes showed 100% chemoselectivity toward the CC bond, and toward the CO bond in the case of Ru. The yield and enantiomeric excess versus time behavior was studied using a large substrate/catalyst ratio. The addition of an organic base to the reaction with Pd complexes enhanced yield and enantiomeric excess. Use of the (S)-diamine ligand in the complex favored the (R)-products. The best results with itaconic acid were 61% yield and 56% enantiomeric excess and 55% yield and 52% enantiomeric excess with α-acetamidocinnamic acid, both catalyzed by Pd(OCOCF3)2 ((S)-6,6′-dimethyl-2,2′- diaminobiphenyl) in 2,2,2-trifluoroethanol. In the case of the Ru catalysts, (S)-1-phenylethanol formed preferentially during hydrogenation of acetophenone. Potassium tert-butoxide stabilized the enantiomeric excess. The best result was 87% yield and 41% enantiomeric excess catalyzed by ((R)-2,2′-Bis(di-p- tolylphosphino)-1,1′-binaphthyl)-RuCl2-((R)-(+)-1-1′- Bi(2-naphtylamine)).
- Rivera, Victor M.,Ruelas-Leyva, J. Pablo,Fuentes, Gustavo A.
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p. 109 - 114
(2013/08/23)
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- Asymmetric synthesis of unnatural amino acids and tamsulosin chiral intermediate
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An efficient and enantioselective hydrogenation of N-acetylamino phenyl acrylic acids was successfully developed by using ruthenium catalyst. This methodology is important in the field of pharmaceuticals and provides a new process for the preparation of unnatural amino acids and tamsulosin chiral intermediate.
- Arava, Veera Reddy,Amasa, Srinivasulu Reddy,Goud Bhatthula, Bharat Kumar,Kompella, Laxmi Srinivas,Matta, Venkata Prasad,Subha
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supporting information
p. 2892 - 2897
(2013/09/02)
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- ChenPhos: Highly modular P-stereogenic C1-symmetric diphosphine ligands for the efficient asymmetric hydrogenation of α-substituted cinnamic acids
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These cats are purrfectionists: The ChenPhos ligands (see structure) showed dramatically higher catalytic activity in the title reaction than their C 2-symmetric predecessor with two dimethylaminoethyl-substituted ferrocenyl(phenyl)phosphanyl groups. The ready accessibility, extreme air stability, and high enantioselectivity, activity, and productivity of these ligands make them very promising for a wide range of practical applications. Copyright
- Chen, Weiping,Spindler, Felix,Pugin, Benoit,Nettekoven, Ulrike
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supporting information
p. 8652 - 8656
(2013/09/12)
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- METHOD FOR PRODUCING OPTICALLY ACTIVE 1,2-BIS(DIALKYLPHOSPHINO)BENZENE DERIVATIVE
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An industrially advantageous method for producing an optically active 1,2-bis(dialkylphosphino)benzene derivative of the present invention is provided. The method is characterized in that a phosphine-borane compound represented by the following general formula (1) is subjected to a deboronation reaction, followed by lithiation, then the reaction product is subjected to reaction with an alkyldihalogenophosphine represented by RaPX′2, and thereafter the reaction product is subjected to reaction with a Grignard reagent represented by RbMgX″ to produce an optically active 1,2-bis(dialkylphosphino)benzene derivative (A). R1 and R2 respectively represent an alkyl group having 1 to 8 carbon atoms, and the number of carbon atoms is different between R1 and R2. Ra is either R1 or R2 and Rb is the other of R1 and R2. X, X′, and X″ each represent a halogen atom.
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Paragraph 0068; 0069; 0070; 0071; 0072; 0073
(2013/07/19)
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- A NOVEL PROCESS FOR THE PREPARATION OF SITAGLIPTIN
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The present invention is directed to a process for the preparation of enantiomerically enriched β-amino acid derivatives which are important chiral building blocks and intermediates in pharmaceuticals. More specifically, the invention pertains to a novel process for practically convenient and economically producing enantiomerically enriched β-amino acid derivatives which are useful for the synthesis of amide inhibitors of dipeptidyl peptidase IV like Sitagliptin, which have been used to treat type 2 diabetes.
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Page/Page column 30
(2013/08/15)
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- Asymmetric hydrogenation of C=C double bonds using Rh-complex under homogeneous, heterogeneous and continuous mode conditions
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A green process for enantioselective hydrogenation of dehydroamino acid derivatives and dimethyl itaconate with a rhodium catalyst modified by a new phosphine-phosphoramidite has been developed providing 97.7-99.8% enantioselectivity in green solvents such as ethylene carbonate and propylene carbonate. The l-DOPA precursor was obtained by simple filtration in 71% yield with 99.5% ee. Dimethyl itaconate was hydrogenated under solvent-free condition at 50 °C with 98.7% ee. The new rhodium complex was heterogenized on a mesoporous Al2O3 support using phosphotungstic acid (PTA) as an anchoring agent and tested in heterogeneous batch and flow reaction modes. The supported catalyst was reused eight times in the batch mode with over 97% ee and used over 12 hours in the flow reaction mode with an average of 97% ee in the asymmetric hydrogenation reaction of (Z)-α-acetamidocinnamic acid methyl ester.
- Balogh, Szabolcs,Farkas, Gergely,Madarasz, Jozsef,Szoellsy, Aron,Kovacs, Jozsef,Darvas, Ferenc,Uerge, Laszlo,Bakos, Jozsef
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supporting information; experimental part
p. 1146 - 1151
(2012/06/18)
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- Efficient kinetic resolution of amino acids catalyzed by lipase AS 'Amano' via cleavage of an amide bond
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Herein the efficient kinetic resolution of non-natural alpha-amino acids catalyzed by lipase AS 'Amano' via cleaving the amide bond is reported. The starting materials were the corresponding amino acid amides and the amino acids were generated with ees of up to 99% with E values of >600. These results indicated that the lipase AS 'Amano' could be a powerful amide hydrolase for the kinetic resolution of amino acid starting from the corresponding amino acid amides.
- Wang, Bo,Liu, Yanfeng,Zhang, Dela,Feng, Yuhong,Li, Jiacheng
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p. 1338 - 1342,5
(2020/09/16)
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- Rigid P-chiral phosphine ligands with tert -butylmethylphosphino groups for rhodium-catalyzed asymmetric hydrogenation of functionalized alkenes
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Both enantiomers of 2,3-bis(tert-butylmethylphosphino)quinoxaline (QuinoxP*), 1,2-bis(tert-butylmethylphosphino)benzene (BenzP*), and 1,2-bis(tert-butylmethylphosphino)-4,5-(methylenedioxy)benzene (DioxyBenzP*) were prepared in short steps from enantiopure (S)- and (R)-tert-butylmethylphosphine-boranes as the key intermediates. All of these ligands were crystalline solids and were not readily oxidized on exposure to air. Their rhodium complexes exhibited excellent enantioselectivities and high catalytic activities in the asymmetric hydrogenation of functionalized alkenes, such as dehydroamino acid derivatives and enamides. The practical utility of these catalysts was demonstrated by the efficient preparation of several chiral pharmaceutical ingredients having an amino acid or a secondary amine component. A rhodium complex of the structurally simple ligand BenzP* was used for the mechanistic study of asymmetric hydrogenation. Low-temperature NMR studies together with DFT calculations using methyl α-acetamidocinnamate as the standard model substrate revealed new aspects of the reaction pathways and the enantioselection mechanism.
- Imamoto, Tsuneo,Tamura, Ken,Zhang, Zhenfeng,Horiuchi, Yumi,Sugiya, Masashi,Yoshida, Kazuhiro,Yanagisawa, Akira,Gridnev, Ilya D.
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supporting information; experimental part
p. 1754 - 1769
(2012/03/11)
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- Chemoenzymatic synthesis of a mixed phosphine-phosphine oxide catalyst and its application to asymmetric allylation of aldehydes and hydrogenation of alkenes
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The chemoenzymatic synthesis of a Lewis basic phosphine-phosphine oxide organocatalyst from a cis-dihydrodiol metabolite of bromobenzene proceeds via a palladium-catalysed carbon-phosphorus bond coupling and a novel room temperature Arbuzov [2,3]-sigmatropic rearrangement of an allylic diphenylphosphinite. Allylation of aromatic aldehydes were catalysed by the Lewis basic organocatalyst giving homoallylic alcohols in up to 57% ee. This compound also functioned as a ligand for rhodium-catalysed asymmetric hydrogenation of acetamidoacrylate giving reduction products with ee values of up to 84%.
- Boyd, Derek R.,Bell, Mark,Dunne, Katherine S.,Kelly, Brian,Stevenson, Paul J.,Malone, John F.,Allen, Christopher C. R.
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experimental part
p. 1388 - 1395
(2012/03/27)
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- Synthesis of novel chiral monophosphine ligands derived from isomannide and isosorbide. Application to enantioselective hydrogenation of olefins
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A new class of monophosphine ligands has been prepared from natural chirality renewable source, 1,4:3,6-dianhydrohexitol compounds, via a nucleophilic substitution process, or a hydrophosphination reaction involving microwave activation. These ligands have been evaluated for the rhodium-catalyzed enantioselective hydrogenation of olefins giving good conversion and enantioselectivity up to 95% and 96% ee, respectively.
- Ibrahim, Houssein,Bournaud, Chloée,Guillot, Régis,Toffano, Martial,Vo-Thanh, Giang
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scheme or table
p. 4900 - 4902
(2012/09/21)
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- Synthesis and antimycobacterial activity of calpinactam derivatives
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Synthesis of calpinactam 1, a fungal antimycobacterial metabolite, utilizing solid-phase peptide synthesis is described. To explore the structure-activity relationships of 1, its derivatives with different amino acids were also synthesized on the basis of the same synthetic strategy. These derivatives were examined for antimycobacterial activity against Mycobacterium smegmatis. Among them, only peptide 6d having d-Ala in place of d-Glu showed moderate activity.
- Nagai, Kenichiro,Koyama, Nobuhiro,Sato, Noriko,Yanagisawa, Chisato,Tomoda, Hiroshi
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supporting information
p. 7739 - 7741
(2013/02/23)
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- Three-hindered quadrant phosphine ligands with an aromatic ring backbone for the rhodium-catalyzed asymmetric hydrogenation of functionalized alkenes
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The three-hindered quadrant phosphine ligands (R)-1-tert- butylmethylphosphino-2-(di-tert-butylphosphino)benzene ((R)-3H-BenzP*) and (R)-2-tert-butylmethylphosphino-3-(di-tert-butylphosphino)quinoxaline ((R)-3H-QuinoxP*) exhibited good to excellent enantioselectivities in the rhodium-catalyzed asymmetric hydrogenation of selected dehydroamino acid derivatives, enamides, and ethenephosphonates.
- Zhang, Zhenfeng,Tamura, Ken,Mayama, Daisuke,Sugiya, Masashi,Imamoto, Tsuneo
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experimental part
p. 4184 - 4188
(2012/06/18)
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- Facile synthesis of chiral diphosphine-containing multiple dendrimeric catalysts for enantioselective hydrogenation
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A new kind of chiral diphosphine PyrPhos-functionalized codendrimers have been synthesized via a liquid-phase strategy in high yields. The resulting dendrimeric PyrPhos ligands were purified by a simple solvent precipitation without the need for chromatographic separation, and well characterized by 1H, 13C and 31P NMR, MALDI-TOF mass spectroscopy as well as elemental analysis. Their rhodium complexes were applied to the asymmetric hydrogenation of α-acetamido cinnamic acids. Excellent enantioselectivities were achieved, which are comparable to those with the corresponding small molecular catalysts. In addition, these codendrimeric catalysts showed better catalytic performance than the dendrimeric catalysts with Rh(PyrPhos) sites located in the focal point of poly(aryl ether) dendrons or in the periphery of poly(propyleneimine) dendrimers.
- Zhao, Liwen,Liu, Ji,Feng, Yu,He, Yanmei,Fan, Qinghua
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p. 2009 - 2015,7
(2020/09/09)
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- Application of tripodal linker units to immobilized rhodium complex catalysts for asymmetric hydrogenation
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The tripodal linker unit with one bromopropyl group and three anchoring silicon atoms was used to immobilize a chiral phosphinerhodium complex catalyst on an ordered mesoporous silica support. The rhodium and phosphorus leaching levels into the reaction solution after asymmetric hydrogenation were lower for this catalyst than for immobilized catalysts prepared using conventional triethoxysilane.
- Fukaya, Norihisa,Onozawa, Shun-Ya,Ueda, Masae,Miyaji, Takayuki,Takagi, Yukio,Sakakura, Toshiyasu,Yasuda, Hiroyuki
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supporting information; experimental part
p. 212 - 214
(2011/04/14)
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- Chiral rhodium complexes derived from electron-rich phosphine-phosphites as asymmetric hydrogenation catalysts
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Two new chiral cationic rhodium(I) complexes derived from electron-rich dicyclohexylphosphine-phosphite ligands were prepared from enantiopure Sharpless epoxy ethers. The best-performing catalyst system, which bears a less bulky methyl ether moiety, exhibited remarkably high enantioselectivity (up to 99% ee) and reactivity (up to >2500 TON) in asymmetric hydrogenation reactions of various functionalized alkenes (α-(acylamino)acrylates, itaconic acid derivatives, α-substituted enol esters and α-arylenamides). Our synthetic methodology has been successfully applied to the enantioselective synthesis of the antiepileptic drug (R)-lacosamide (Vimpat).
- Etayo, Pablo,Nunez-Rico, Jose L.,Vidal-Ferran, Anton
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experimental part
p. 6718 - 6725
(2012/02/05)
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- Aminolytic reaction catalyzed by d-stereospecific amidohydrolases from Streptomyces spp
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From investigation of 2000 soil isolates, we identified two serine-type amidohydrolases that can hydrolyze d-aminoacyl derivatives from the culture supernatant of Streptomyces species 82F2 and 83D12. The enzymes, redesignated as 82F2-DAP and 83D12-DAP, were purified for homogeneity and characterized. Each enzyme had molecular mass of approximately 40 kDa, and each showed moderate stability with respect to temperature and pH. Among hydrolytic activities toward d-aminoacyl-pNAs, the enzymes showed strict specificity toward d-Phe-pNA, but showed broad specificity toward d-aminoacyl esters. The specific activity for d-Phe-pNA hydrolysis of 82F2-DAP was ten-fold higher than that of 83D12-DAP. As a second function, each enzyme showed peptide bond formation activity by its function of aminolysis reaction. Based on results of d-Phe-d-Phe synthesis under various conditions, we propose a reaction mechanism for d-Phe-d-Phe production. Furthermore, the enzymes exhibited peptide elongation activity, producing oligo homopeptide in a one-pot reaction. We cloned the genes encoding each enzyme, which revealed that the primary structure of each enzyme showed 30-60% identity with those of peptidases belonging to the clan SE, S12 peptidase family categorized as serine peptidase with d-stereospecificity.
- Arima, Jiro,Ito, Hitomi,Hatanaka, Tadashi,Mori, Nobuhiro
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experimental part
p. 1460 - 1469
(2012/01/12)
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- Ferrocenyl-aryl based trans-chelating diphosphine ligands: Synthesis, molecular structure and application in enantioselective hydrogenation
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Potentially trans-chelating diphosphine ligands based on a ferrocenyl-aryl backbone were synthesised in a four-step sequence and the molecular structures in the solid state of two representatives were determined by X-ray diffraction. High throughput screening of these ligands in rhodium-, ruthenium- and iridium-mediated hydrogenations of a variety of alkenes and ketones revealed that these ligands can deliver high enantioselectivity for alkenes (up to 98% ee) but are less selective when ketones are used as the substrates. The coordination behaviour of one ligand in its square planar palladium and platinum dichloride complexes was studied by 31P NMR and only trans-chelated complexes, together with oligomeric by-products, were observed. Reaction with the (p-cymene)ruthenium dichloride dimer, [RuCl2(pcymene)] 2, resulted in a mixture of diastereomeric complexes.
- Schuecker, Raffael,Mereiter, Kurt,Spindler, Felix,Weissensteiner, Walter
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scheme or table
p. 1063 - 1074
(2010/06/17)
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- Resolution of N-protected amino acid esters using whole cells of Candida parapsilosis ATCC 7330
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Whole cells of Candida parapsilosis ATCC 7330 were used for the resolution of N-acetyl amino acid esters. Excellent enantioselectivities (E = 40 to >500) were achieved for the resolution of N-protected protein and non-protein amino acid esters giving good yields (28-50%) and high enantiomeric excesses (up to >99%) for both enantiomers.
- Stella, Selvaraj,Chadha, Anju
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experimental part
p. 457 - 460
(2010/06/21)
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- Novel, tunable, and efficient chiral bisdihydrobenzooxaphosphole ligands for asymmetric hydrogenation
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"Chemical Equation Presented" A series of novel, efficient, air-stable, and tunable chiral bisdihydrobenzooxaphosphole ligands (BIBOPs) were developed for rhodium-catalyzed hydrogenations of various functionalized olefins such as α-ary lenam ides, α-(acylamino)acrylic acid derivatives, β-(acylamino)acrylates, and dimethyl itaconate with excellent enantioselectivities (up to 99% ee) and reactivities (up to 2000 TON)
- Tang, Wenjun,Qu, Bo,Capacci, Andrew G.,Rodriguez, Sonia,Wei, Xudong,Haddad, Nizar,Narayanan, Bikashandarkoil,Ma, Shengli,Grinberg, Nelu,Yee, Nathan K.,Krishnamurthy, Dhileep,Senanayake, Chris H.
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supporting information; experimental part
p. 176 - 179
(2010/03/30)
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- Acceleration of enantioselective hydrogenation of olefins over Pd/C by cinchonidine as a chiral modifier. Comparison with cinchonine, pseudoenantiomer
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The performance of cinchonidine (CD) and cinchonine (CN) as chiral modifiers in enantioselective hydrogenation over Pd/C were compared in different concentrations. The catalytic hydrogenation with CD always occurred in better ee and at faster rate than that with CN. The difference is not attributable to the adsorption properties of the modifiers, but to the intrinsic enantio differentiation that accompanies the reaction acceleration.
- Sugimura, Takashi,Ogawa, Hiroyuki
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supporting information; scheme or table
p. 232 - 233
(2010/08/22)
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- Bis((2-methoxymethyl)pyrrolidine)phosphine as effective chiral auxiliary for the stereoselective synthesis of chiral ferrocenyl diphosphines
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The bis(2-methoxymethyl pyrrolidine)phosphine moiety is shown to be a very effective chiral auxiliary for the ortho-and diastereoselective lithiation of ferrocene, thereby allowing the highly selective attachment of various electrophiles to the cyclopentadienyl ring of ferrocene. The potential of the methodology is demonstrated by the synthesis of Kephos, a new family of ferrocenyl diphosphines and of OH-Taniaphos derivatives.
- Lotz, Matthias,Pugin, Benoit,Kesselgruber, Martin,Thommen, Marc,Spindler, Felix,Blaser, Hans-Ulrich,Pfaltz, Andreas,Schoenleber, Marc
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scheme or table
p. 1199 - 1202
(2010/11/02)
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- Is restricted M-P rotation a common feature of enantioselective monophos catalysts? An example of restricted Rh-P rotation in a secondary phosphine complex
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The enantioselective hydrogenation catalyst [Rh(α-CgPH) 2(cod)]BF4, (CgPH = 6-phospha-2,4,8-trioxa-adamantane) exists in solution as a mixture of two slowly interconverting rotamers, one with C2-and the other with C1-symmetry.
- Jankowski, Piotr,McMullin, Claire L.,Gridnev, Ilya D.,Orpen, A. Guy,Pringle, Paul G.
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scheme or table
p. 1206 - 1209
(2010/11/02)
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- Chiral mixed secondary phosphine-oxide-phosphines: High-performing and easily accessible ligands for asymmetric hydrogenation
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P&O: Combining secondary phosphine oxides (SPOs) with phosphines leads to highly effective chiral bidentate ligands for transition-metal-based catalysts. JoSPOphos and TerSPOphos are readily accessible from inexpensive starting materials. The steric and electronic properties of these modular ligands can be easily tuned. In the asymmetric hydrogenation of functionalized alkenes, their rhodium complexes reacted to give enantioselectivities of up to 99% ee and turnover frequencies of up to 20000 h-1 Chemical equation Presented
- Landert, Heidi,Spindler, Felix,Wyss, Adrian,Blaser, Hans-Ulrich,Pugin, Benoit,Ribourduoille, Yann,Gschwend, Bjoern,Ramalingam, Balamurugan,Pfaltz, Andreas
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scheme or table
p. 6873 - 6876
(2010/12/19)
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- The influence of molecular structure and crystallization time on the efficiency of diastereoisomeric salt forming resolutions
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Reciprocal resolutions between compounds (racemates and enantiomers) with similar structures have been examined. Amongst structurally similar compounds (so called relative structures) several N-acyl amino acids and amino acid esters were investigated. A part of the resolving agent or the racemic compound could be replaced by an achiral compound with a relative structure and an additive could occasionally improve significantly the efficiency of the resolution. Both the kinetic and the thermodynamic controls were observed as governing factors of the reciprocal resolutions.
- Palovics, Emese,Schindler, Jozsef,Faigl, Ferenc,Fogassy, Elemer
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experimental part
p. 2429 - 2434
(2010/12/25)
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- Highly modular P-OP ligands for asymmetric hydrogenation: Synthesis, catalytic activity, and mechanism
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A library of enantiomerically pure P-OP ligands (phosphine-phosphite), straightforwardly available in two synthetic steps from enantiopure Sharpless epoxy ethers is reported. Both the alkyloxy and phosphite groups can be optimized for maximum enantioselectivity and catalytic activity. Their excellent performance in the Rhcatalyzed asymmetric hydrogenation of a wide variety of functionalized alkenes (26 examples) and modular design makes them attractive for future applications. The lead catalyst incorporates an (S)-BINOL-derived (BINOL= 1,1'bi-2-naphthol) phosphite group with computational studies revealing that this moiety has a dual effect on the behavior of our P-OP ligands. On one hand, the electronic properties of phosphite hinder the binding and reaction of the substrate in two out of the four possible manifolds. On the other hand, the steric effects of the BINOL allow for discrimination between the two remaining manifolds, thereby elucidating the high efficiency of these catalysts.
- Fernandez-Perez, Hector,Donald, Steven M. A.,Munslow, Ian J.,Benet-Buchholz, Jordi,Maseras, Feliu,Vidal-Ferran, Anton
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supporting information; experimental part
p. 6495 - 6508
(2010/10/02)
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- ORGANIC INORGANIC COMPOSITE MATERIAL AND UTILIZATION THEREOF
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The invention has an object to obtain an organic inorganic composite material having high activity and high selectivity, and suitable as a catalyst material having small elution of an active metal from a carrier, and further to obtain an organosilicon compound suitable for the preparation of the composite material. The composite material is an organic inorganic composite material comprising an organosilicon compound having at least two groups containing reactive silicon at a molecular end, bonded to one silicon atom constituting the organosilicon compound, and an inorganic oxide material, the organosilicon compound and the inorganic oxide material being bonded to each other through a plurality of groups containing reactive silicon of the organosilicon compound. The organosilicon compound is represented by the following general formula (1) or (2). Formula (1) wherein symbols are the same as defined in claim 17. Formula (2) wherein symbols are the same as defined in claim 18.
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Page/Page column 21-22
(2010/11/19)
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- NEW ORTHO-FUNCTIONALIZED P-CHIRAL ARYLPHOSPHINES AND DERIVATIVES: THEIR PREPARATION AND USE IN ASYMMETRIC CATALYSIS
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The invention relates to novel organo phosphorus P-chiral optically active compounds of formula (I) having a hydroxyl, mercapto, amino, carboxyl, sulfonyl group on aryl near a phosphorus atom, to the preparation and the use thereof in then asymmetrical catalysis of unsaturated compounds. Novel acylphosphine optically pure ligands embodied in the form of transition metal complexes exhibit an increased activity and enantloselectivity, in particular in asymmetrical hydrogenation, in comparison with the same type Uganda such as DiPAMP.
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Page/Page column 21
(2010/07/04)
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- BIS(FERROCENYLPHOSPHINO) FERROCENE LIGANDS USED IN ASSYMETRIC HYDROGENATION REACTIONS
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Abstract Compounds of the formula (I) in the form of racemates, enantiomerically pure diastereomers or a mixture of diastereomers, where the radicals R1 are identical or different and are each C1-C4-alkyl; m is 0 or an integer from 1 to 4; n is 0 or an integer from 1 to 3; p is 0 or an integer from 1 to 5; R2 is an aromatic hydrocarbon radical or a C-bonded heterohydrocarbon radical and R3 is an aliphatic or C-bonded heteroaliphatic hydrocarbon radical; R2 and R3 are identical or different and are each an aliphatic or C-bonded heteroaliphatic hydrocarbon radical; R4 is an unsubstituted or C1-C6-alkyl-, C1-C6-alkoxy- or halogen-substituted hydrocarbon radical; and A is a secondary amino group, are ligands for metal complexes which are suitable as catalysts for homogeneous enantioselective hydrogenation.
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Page/Page column 20-21
(2010/07/04)
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- NEW PHOSPHINE-PHOSPHITE LIGANDS
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The invention relates to new phosphine-phosphite ligands for the preparation of a catalyst for the asymmetric hydrogenation of unsaturated hydrocarbon compounds, methods for their preparation and use thereof.
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Page/Page column 29
(2009/04/25)
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- Divalent samarium triflate mediated stereoselective pinacol coupling of planar chiral phosphanyl and phosphoryl ferrocenecarbaldehyde
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The pinacol coupling reaction of (Rp)-2-diphenylphosphanyl ferrocenecarbaldehyde (1) was smoothly mediated by divalent samarium triflate to give (R,R)-diol 2a predominantly, whereas the use of samarium(II) iodide resulted in low selectivity as described in the previous literature. In contrast, the coupling reaction of (Rp)-2-diphenylphosphoryl ferrocenecarbaldehyde (3) with Sm(OTf)2 gave the (S,S)-diol as the major isomer, which was the opposite stereochemistry of that obtained in the reaction with 1. The rhodium complexes of diphosphanes 2a were good catalysts for the asymmetric hydrogenation of α-acetamidocinnamic acid, and the product was obtained quantitatively with up to 92 % ee.
- Fukuzawa, Shin-Ichi,Oura, Ichiro,Shimizu, Kenta,Kato, Minoru,Ogata, Ken-Ichi
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experimental part
p. 716 - 720
(2009/07/19)
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- BIDENTATE SECONDARY PHOSPHINE OXIDE CHIRAL LIGANDS FOR USE IN ASYMMETRIC ADDITION REACTIONS
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Compounds of the formula I, in the form of mixtures comprising predominantly one enantiomer or in the form of pure enantiomers, secondary phosphine-Q-P*(=O)HR1 (I) in which secondary phosphine is a C-bonded, secondary phosphine group -P(R) 2; in which R is in each case independently hydrocarbon radicals or heterohydrocarbon radicals; Q is a bivalent, achiral, aromatic base skeleton, a bivalent, achiral ferrocene base skeleton, an optionally substituted bivalent cycloalkane or heterocycloalkane skeleton, or a C 1-C 4-alkylene skeleton, and in which base skeletons a secondary phosphine group is bonded directly to a carbon atom, or, in the case of cyclic base skeletons, directly to a carbon atom or via a C1-C 4-alkylene group, and in which base skeletons a P-chiral group -P*(O)HR1 is bonded to a carbon atom such that the phosphorus atoms are linked via 1 to 7 atoms of a carbon chain optionally interrupted by heteroatoms from the group of O, S, N, Fe or Si; P* is a chiral phosphorus atom; and R1 is a hydrocarbon radical, a C-bonded heterohydrocarbon radical or a ferrocenyl radical, with the proviso that R1 is an achiral ferrocenyl radical when Q is an achiral ferrocenyl base skeleton. Metal complexes of these ligands in a molarratio of ligand to metal of about 1.3:1 to 0.9:1are homogeneous catalysts for asymmetric addition reactions, particularly hydrogenations.
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Page/Page column 43-45
(2009/06/27)
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- BIDENTATE CHIRAL LIGANDS FOR USE IN CATALYTIC ASYMMETRIC ADDITION REACTIONS
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Compounds of the formula (I), in the form of mixtures comprising predominantly one diastereomer or in the form of pure diastereomers, Z1-Q-P*R0R1 (I) in which Z1 is a C-bonded, secondary phosphine group -P(R)2; in which R is in each case independently hydrocarbon radicals or heterohydrocarbon radicals, or Z1 is the -P*R0R1 group; Q is a bivalent, achiral, aromatic base skeleton, a bivalent, achiral ferrocene base skeleton, an optionally substituted bivalent cycloalkane or heterocycloalkane skeleton, or a C1-C4-alkylene skeleton, and in which base skeletons a secondary phosphine group Z1 is bonded directly to a carbon atom, or, in the case of cyclic base skeletons, directly to a carbon atom or via a C1-C4-alkylene group, and in which base skeletons a P-chiral group -P*R0R1 is bonded directly to a carbon atom, or, in the case of cyclic base skeletons, directly to a carbon atom or via a C1-C4-alkylene group to a carbon atom such that the phosphorus atoms are linked via 1 to 7 atoms of a carbon chain optionally interrupted by heteroatoms from the group of O, S, N, Fe or Si; P* is a chiral phosphorus atom; R0 is methyl or hydroxyl, and R0 is methyl when Z1 is the -P*R0R1 group; and R1 is a C-bonded optically enriched or optically pure chiral, mono- or polycyclic, nonaromatic hydrocarbon or heterohydrocarbon radical which has 3 to 12 ring atoms and 1 to 4 rings and which has a stereogenic carbon atom at least in the α position to the P-C bond; Metal complexes of these ligands are homogeneous catalysts for asymmetric addition reactions, particularly hydrogenations.
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Page/Page column 53-57
(2009/06/27)
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