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Showing 1 to 20 of 23 for “"chiral amines"”.
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Directed evolution of amino acid dehydrogenases for biocatalysis of chiral amines
… of amino acid dehydrogenases for biocatalysis of chiral amines, focusing on two crucial features for successful directed evolution experiments. A first key aspect is the development of technologies allowing the screening of large libraries of enzyme variants to explore sequence space efficiently. …
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New Strategies and Transformations for the alpha-Functionalization of Amines to Access Chiral Amines
… methodologies to prepare alpha-functionalized amines, especially chiral amines have been studied in this work. Specifically, we focused our work on introducing alpha-functionalization to amines through C–C forming processes. This thesis work is inspired by the vitamin B6 transamination process: …
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The Development of Palladium and Cobalt-Catalyzed Methods for the Syntheses of alpha-Trifluoromethyl and Alkyl Amines
… of methodologies for the construction of chiral amines in organic synthesis. Amongst these chiral amines, a-trifluoromethyl and alkyl amines are an important subclass that have been sought after because of their relevance in drug discovery. With respect to a-trifluoromethyl amines, the …
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Extension of Chromatographically - Derived Molecular Recognition Concepts to Stereoselective Reactions and Transformations
Analogues of chiral stationary phases (CSPs) and analogues of enantiomeric analytes separable upon the CSPs were employed in the investigation of stereoselective reactions and transformations. N-(3,5-dinitrobenzoyl)phenylglycine and N-(3,5-dinitrobenzoyl)leucine were used to study the …
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Mechanistic Aspects of Enantioselective Complexation
… of synthetic, brush-type liquid chromatographic chiral stationary phases (CSPs) has been investigated. The design and evaluation of a new family of $\pi$-basic CSPs which utilize these intercalative effects to enhance enantioselectivity is discussed. These CSPs, designed from mechanistic …
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Synthesis of new recoverable catalysts and their application in asymmetric reduction of ketimines with trichlrosilane
Obtaining chiral amines from ketones via imine intermediates represents an attractive strategy that opens a straightforward route to valuable building blocks for the pharmaceutical and other fine chemicals industries. Metal-free oranocatalysis can be viewed as an attractive and broadly applicable …
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Über die Entwicklung neuer Methoden zur N-Arylierung von Sulfoximinen und die Synthese von Diarylphosphinylsulfoximinen als Liganden in der asymmetrischen Metallkatalyse
… of different aryl-alkyl-imines leading to useful chiral amines with very high enantiomeric excesses (up to 98% ee). The catalyst performance can be tuned by the sulfoximine and the diarylphosphine moiety as well as iodine as additive.
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Chemistry with chiral lithium amides: enantiotopic group and face-selective reactions
… enolate to the nitrogen atom. Seven interesting chiral amines have been synthesized and applied into the enolate chemistry of two interesting precursors of synthesis of natural products: 1,4- cyclohexanedione monoethylene ketal and tropinone.The aldol reaction between the lithium enolate of …
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Multicomponent Diels-Alder Sequences of 1-Aminodendralenes
… generated in situ with a catalytic amount of a chiral amine. While there have been many reports of Diels-Alder reactions of 1-amino-1,3-butadienes and 1-amino-3-siloxy-1,3-butadienes, there has been only one involving a semi-cyclic 1-amino[3]dendralene. There have been few examples which combine …
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Multicomponent Diels-Alder Sequences of 1-Aminodendralenes
… generated in situ with a catalytic amount of a chiral amine. While there have been many reports of Diels-Alder reactions of 1-amino-1,3-butadienes and 1-amino-3-siloxy-1,3-butadienes, there has been only one involving a semi-cyclic 1-amino[3]dendralene. There have been few examples which combine …
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Part I. Anionic Acyl Transfer Catalysis;Part II. Enantioselective alcoholysis of Acyl Donors;Part III. Enantioselective N-acylation
… e.g., for catalytic kinetic resolution of chiral amines.</p><p>From 2003 to 2009, our group developed four generations of amidine-based enantioselective acyl transfer catalysts(ABCs) and applied them successfully to the kinetic resolution of chiral alcohols. Compared with chiral alcohols, …
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The development of novel hetrogeneous catalysts for the hydrogenation of prochiral imines
… for the enantioselective hydrogenation of prochiral imines. Work has centred on the support of homogeneous catalysts, with the intention of establishing a heterogeneous catalyst without loss of activity. Initially, established heterogeneous systems were investigated. As the methyl pyruvate …
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Exploring the Functionality and Application of Cyclic Phosphazanes
… active ligands for inorganic electrolytes, and chiral discrimination reagents for enantiomeric amines were explored. Firstly, the extensive versatility of cyclodiphosphazanes in synthesising P(III), P(V), or mixed-valence inorganic macrocycles is demonstrated in this thesis. Despite many of the …
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OPPORTUNITIES AND CHALLENGES OF BIOCATALYSIS IN PHARMACEUTICAL SCIENCES: DEVELOPING TAILORED BIOCATALYSTS FOR SYNTHETIC APPLICATIONS
… substrate scope toward sterically demanding amines. Directed evolution efforts aimed at improving asymmetric amination are currently ongoing. Overall, this work highlights how biocatalysis is consolidating its role as an essential resource in modern synthetic chemistry. Technological advances …
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Zur asymmetrischen Synthese von Beta-Thio-Alpha-Aminosäuren
… of beta-Thio-alpha-Aminoacids who are containing chiral centers in alpha- und beta-position. There are different approaches towards the diastereo- und enantioselektive synthesis of these amino acids described using chiral Amines or the SAMP-/RAMP-hydrazone methodology. Nearly all retrosynthetic …
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Part I. Rhodium-catalyzed asymmetric functionalization of allylic amines Part II. Harnessing kinetic driving forces in alkyne metathesis for the synthesis of complex molecular architectures
… asymmetric functionalization of allylic amines to form chiral products such as β-branched amides and esters, and γ-branched amines. We developed a modular synthetic strategy that enables the diversification of a single allylic amine scaffold into many value-added products. Chiral, …
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Asymmetrische Pinakolkupplungen
… as starting materials and the other to introduce chirality using chiral coupling reagents. In this Ph. D. thesis both strategies were investigated. Using the SAMP / RAMP hydrazone method several a-chiral aldehydes and ketones were obtained in a four step procedure in moderate to excellent …
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Photochemistry of dibenzobarrelenes and [alpha]-adamantyl acetophenones in both the solution and crystalline state
… geometric requirements for hydrogen abstraction. Chiral crystals of carboxylic acid-amine salts were synthesized for solid state asymmetric induction studies. Some of these chiral salts were made from a prochiral, carboxylic acid group-containing a-adamantyl acetophenone (119) and optically pure …
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Synthesis and reactivity of alpha-trialkylsilyl alpha-amino acids
… substrates, as well as various reactants such as chiral amines, ureas, or carbamates as sources of the chiral information. Carbamates were confirmed as the mostly efficient N-H sources for rhodium(II)-catalysed reaction. A diastereoselective N-H insertion reaction was attempted between a …
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New Pd and Cu-based catalysts for carbon-heteroatom bond formation
… enantioselectively to generate [alpha]-branched amines. The system can transform a wide variety of substituted styrenes, including trans-, cis-, and [beta]-disubstituted styrenes. In addition, our extension to copper-catalyzed hydroamination reactions of unactivated aliphatic olefins is reported. …
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