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Showing 1 to 20 of 52 for “"Absolute Configuration"”.
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The Synthesis, Absolute Configuration, and Enantiomeric Purity of Chiral Allenes
Made available in DSpace on 2014-12-13T20:10:29Z (GMT). No. of bitstreams: 1 7913390.pdf: 3033849 bytes, checksum: f43e3c5a0245f56c4d996c38d99c6981 (MD5) Previous issue date: 1978
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Development of porphyrin tweezer system for determining absolute configuration of chiral molecules via ECCD
… OF PORPHYRIN TWEEZER SYETEM FOR DETERMINING ABSOLUTE CONFIGURATION OF CHIRAL MOLECULES VIA ECCDByXiaoyong Li This dissertation focuses on three parts. The first portion introduces the concept of exciton coupled circular dichroism (Chapter I) and the rationale about how we design and prepare …
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A critical assessment of possible pitfalls in absolute configuration assignment using Vibrational Circular Dichroism
… routinely applicable for the determination of absolute configurations. The VCD technique is gaining interest in mainly pharmaceutical industry and the technique also has been accepted by regulatory agencies (e.g. FDA) as a proof of absolute configuration (AC). Since a misassignment can have …
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Syntheses and Determinations of Absolute Configuration and Enantiomeric Composition of Chiral Oxaziridines and Epoxides
Made available in DSpace on 2014-12-13T20:10:34Z (GMT). No. of bitstreams: 1 7913591.pdf: 4509905 bytes, checksum: cc327a7c32ec6093eae05e3f286c0cec (MD5) Previous issue date: 1978
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Synthesis and determination of the absolute configuration of Armatol A through a polyepoxide cyclization cascade : revision of the proposed structures of Armatols A-F
… Coupling, Synthesis, and Determination of the Absolute Configuration of Armatol A A stereoselective synthesis of a bromooxepane ring via a bromonium-initiated epoxide-opening cyclization was explored. Functionalization of the primary alcohol formed from this cascade allowed for a variety of …
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Enantioselective Adsorption of 1,3-Dithiolane-1-Oxides and Related Compounds on Liquid Chromatographic Amino Acid-Derived Chiral Stationary Phases (Resolution, Enantiomers, Sulfoxides)
… analytes which, in turn, allow assignment of the absolute configuration of many cyclic sulfoxides on the basis of chromatographic elution order. Confirmation of these assignments is provided by circular dichroism spectroscopy, NMR spectroscopy in the presence of a chiral solvating agent and …
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Synthesis and Determination of the Absolute Configuration of the Bicyclic Guanidine Core of Batzelladine A and the Development of a Novel [4+2] Inverse Electron Demand Hetero Diels -Alder Cycloaddition and Its Application Toward the Synthesis of the Tricyclic Guanidine Fragment Within Batzelladine A
… guanidine portion including elucidation of the absolute configuration of the bicyclic guanidine and the development of a novel [4+2] inverse electron demand hetero Diels-Alder cycloaddition amendable for synthesis of the tricyclic guanidine portion. These studies culminated in the first …
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The Design and Utility of Chiral Derivatizing Agents
… determination of enantiomeric purity and absolute configuration of various asymmetric primary amines and secondary carbinols. The resolution and assignment of absolute configuration of several chiral chloroformates is presented along with a discussion of the enhanced stability of …
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Enantioselective lateral lithiation-substitution of o-ethyl- and o-benzyl-N-pivaloylanilines: Studies of a pathway of stereoinformation transfer
… 80% for reactions with most electrophiles. The absolute configuration at the benzylic carbon is the same regardless of whether stannyl or stannyl chlorides, alkyl halides, or aldehydes and ketones are used as the electrophile.
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The optical resolution of albuterol
… was isolated as an acetate salt. The inferred absolute configuration of the resolved acetonide was assessed by 1H NMR analysis of its (R)-Mosher ester, and confirmed by an X-ray structural determination of its (R)-phenylethylurea derivative. The acetonide derivative of (rac)-albuterol has been …
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Enantioselective Syntheses and Chemical Investigations of Plant-Derived Bioactive Volatile Compounds
… valencane ring system, (c) determination of the absolute configuration of (+)-nootkatone, and (d) rearrangements of various sesquiterpenoid derivatives; the latter focuses on the construction ofƒndelta, epsilon-unsaturated carbonyl compounds, hetero Pauson-Khand substrates, via [3,3]-sigmatropic …
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The Modified Stereospecific Stille Reaction: Palladium-Catalyzed Cross-Coupling Reactions Involving Secondary and Tertiary Alkyl Carbastannatranes
… tolerates a wide range of functional groups with absolute configuration. In the third chapter, this work has been extended to the use of acyl electrophiles, which undergo Pd-catalyzed cross-coupling reactions with secondary alkylcarbastannatranes with exceptional stereofidelity and with net …
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Asymmetrische Synthese von cyclischen allylischen S-tert-Butylsulfonen : Pd-katalysierte kinetische Racematspaltung racemischer Allylcarbonate und zur Struktur chiraler, cyclischer allylischer Alpha-tert-Butylsulfonyl-Carbanionen
… excellent enantioselectivities (89-98 %). The absolute configuration of the sulfones was determined to be 'S' by crystal analysis. Another aim of the project was the investigation of the kinetic resolution occurring during the Pd-catalyzed sulfonylation of the racemic carbonates. Therefore the …
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Organocatalysts for the asymmetric reduction of aromatic ketimines with trichlorosilane
… investigation shows that the product configuration is controlled by the nature of the side chain of the catalyst scaffold (e.g., i Pr vs Me, as in 197c and 208c), so that catalysts of the same absolute configuration may induce the formation of the opposite enantiomers of the product. …
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Broad-Spectrum Synthesis of Enantiomerically Pure Lactones
… hence are of biological interest. Assignments of absolute configuration to the lactone enantiomers and their precursors typically attend these syntheses. For some lactones, possessing suitable NMR spectra, direct determination of enantiomeric purity is possible using the chiral solvent (R)-(-)-2, …
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Nitroalkene (4+2) cycloadditions of achiral and chiral vinyl ethers. The stereochemical consequence of the Lewis acid promoter and studies toward the total synthesis of (+)-pretazettine
… available from the chiral auxiliary of a single absolute configuration by judicious selection of the Lewis acid promoter, Ti(Oi-Pr)$\sb{2}$Cl$\sb{2}$ (98% ee, ($-$)) or methylaluminum bis-(2,6-diphenylphenoxide) (MAPh) (93% ee, (+)). Propenyl ethers derived from ($-$)-6 undergo endo-selective …
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Design, synthesis, and exploration of a chimeric antioxidant and new crosslinkers for molecular imprinting
… Racemic and Scalemic imprinting as well as absolute configuration (AC) determination were also studied throughout this work to improve MIP utility in academia and industry. Chiral OMNiMIP crosslinkers (S)-2-methacrylamidopropyl methacrylate (L-NALA) and N,O-bis-methacryloyl L-serine (NOS) …
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