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Showing 1 to 20 of 66 for “"enantiomerically pure"”.
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Broad-Spectrum Synthesis of Enantiomerically Pure Lactones
A general synthetic approach that affords both enantiomers of chiral lactones is described. The key step involves the automated multigram chromatography of diastereomeric derivatives of a racemic intermediate. The generality of the method is demonstrated by the synthesis of ring-saturated lactones …
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A new synthesis of enantiomerically pure bicyclic ketones. Total synthesis of the diterpenoids (-)-Kolavenol and (-)-Agelasine B
… thesis describes the synthesis of a series of enantiomerically pure cis-fused bicyclic trimethylstannyl ketones 124, 132 and 133. The bicyclic ketones were prepared by means of a methylenecyclohexane, methylenecyclopentane or anethylidenecyclopentane annulation sequence using the bifunctional …
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The Design and Synthesis of Novel Chiral Z-Nitrones with Applications Towards the Syntheses of Enantiomerically Pure 4-Hydroxy Amino Acids
<p>A number of 4-hydroxy amino acids have been synthesized via 1,3-dipolar cycloadditions of novel Z-nitrones and substituted olefins. Three achiral nitrones were synthesized in pursuit of a conformationally stable yet reactive Z-nitrone. The carboisopropoxynitrone was determined to be the best …
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Asymmetrische Totalsynthese von 16(S)-Iloprost und 3-Oxa-16(S)-Iloprost mittels der Azoen-Strategie
… block was obtained diastereomerically and enantiomerically pure in 9 steps with an overall yield of 22%-26%. Key steps are the diastereoselective alkylation of an acylated oxazolidinone, the synthesis of an Enantiomerically pure Weinreb-Amid and its coupling with a monolithiated stannane …
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Chirality Transfer in Acyclic Allylic Systems and New Pd-Catalyzed Heck Reaction/C-H Activation Cascades
… enantioselective, even at 110 °C and led to enantiomerically pure allylic phosphine oxides. The substitution pattern of the substrate and the reaction conditions were fully optimized.The chirality transfer concept was also used intermolecularly in asymmetric allylic substitution reactions. …
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Werner clathrates with potential chiral selectivity : preliminary investigations
… as host complex made from enantiomerically pure amine ligand and from the racemic mixture, as well as its clathrate with sec-butylbenzene have been determined by x-ray diffraction.
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Enantioenriched Homoaldol Products, Beta-Substituted Ketones, Isoxazolines, and Beta-Lactams Through Elaboration of Allylamine Asymmetric Homoenolate Equivalents: Synthesis and Elucidation of Reaction Pathways
… to 84:16. An isoxazoline was converted into an enantiomerically pure beta-lactam via a beta-amino alcohol and a beta-amino acid in six synthetic steps in 25% overall yield.
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Asymmetrische Synthese von bicyclischen Alpha-Aminosäuren durch intramolekulare Pauson-Khand-Reaktion von l-Alkenylsulfoximinen und Festphasensynthese mit Allylsulfoximinen
… a substituent in beta-position. Starting from enantiomerically pure (S)-N,S-Dimethyl-S-phenylsulfoximine allylic sulfoximines could easily be prepared in 55-70% yield following a well established addition elimination isomerization route. A regio and diastereoselective allylation of …
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High oxidation state molybdenum and tungsten imido alkylidene and metallacycle chemistry : catalytic asymmetric olefin metathesis and mechanistic investigation
Enantiomerically pure molybdenum imido alkylidene complexes of the type Mo(NAr)(CHCMe₂Ph)[Ar'](THF), which contained 3,3'-diaryl (Ar' = Mes (21), Ph (22)) substituted binaphtholate ligands, were prepared and structurally characterized. Complex 21 was a trigonal bipyramidal anti alkylidene complex; …
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Axial chirale Phosphite als Liganden in der enantioselektiven Rhodium-katalysierten Hydrierung
In the pharmaceutical and agrochemical industry enantiomerically pure substances become more and more important as drugs or chiral building blocks. The Rhodium-catalyzed hydrogenation is a very effective way to produce such enantiomerically pure substances. Activity and selectivity of the …
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Enantioselective synthesis using bromoacetals.
… of research into the preparation of racemic and enantiomerically pure arylpropanoic acids is briefly reviewed by reference to some of the more important synthons. Some of the more general procedures that have been developed for the construction of arylpropanoic acids are discussed. The …
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The synthesis and evaluation of halo and protio enol lactone Pro-Val pseudodipeptides as potential inhibitors of human leukocyte elastase
… and protio enol lactones. In this study, the enantiomerically pure disubstituted protio and halo enol lactones 11a-c and 12a-b were prepared as potential inhibitors of the serine protease human leukocyte elastase (HLE). These lactones are incorporated into a Pro-Val pseudodipeptide in order to …
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Probing the mechanism of the asymmetric alkylation of pseudoephedrine amides
… issues in organic chemistry today is to create enantiomerically pure compounds. Racemic products, containing both enantiomers in equal quantities, can result is tragic consequences as in the notorious example of the thalidomide drug. A widely used method to synthesize enantiomerically pure …
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Synthesis of aza-tryptophan derivatives.
… A variety of attempts to synthesize the enantiomerically pure form of 7-azatryptophan were considered. Of those Evans' asymmetric glycine enolate aldol condensation, Baldwin's copper catalyzed Grignards for azridine ring opening, and Jackson's coupling reaction with aryl iodides were …
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Synthesis of new sulfoximines for asymmetric synthesis and pseudopeptides
… to develop methods, which make a wide variety of enantiomerically pure sulfoximine derivatives accessible. This thesis is mainly centered on the search of new synthetic methodologies and the improvement of existing ones in order to prepare a variety of sulfoximine compounds conveniently. The …
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Auxiliares quirales derivados de carbohidratos: Nuevas aplicaciones
… areas, describing a wide range of new enantiomerically pure compounds of potential interest.
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Two enantiodivergent syntheses of balanol and the chemoenzymatic synthesis of oseltamivir
… reagent and its application to the synthesis of enantiomerically pure ~-amino alcohols. This methodology has been exploited in the formal enantiodivergent synthesis of the (+)- and (-)-isomers of balanol. Also described is a second generation approach to both balanol enantiomers; each commencmg …
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(--)-Sparteine Mediated Asymmetric Synthesis Through Conjugate Addition of Allylic and Benzylic Organolithium Species: Development of a Methodology and Its Application Toward a Total Synthesis
… with the synthesis of diastereo-, and enantiomerically pure 2,3,4-trisubstituted gamma-lactams in high yield. In addition, conjugate addition of the allylic organolithium species with N-protected 4-pyridones provides high yields of the corresponding 1,4-addition adduct with high …
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Design and synthesis of small-molecule inhibitors as anti-malarial and anti-serpin agents
… discussed concerns the design and synthesis of enantiomerically pure anti-malarial compounds containing chiral 1,2-aminoalcohol moiety. In addition, the synthesis and biological evaluation of several highly potent, novel, polygalloyl PAI-1 inhibitors based on common carbohydrates and tethers of …
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