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Showing 1 to 11 of 11 for “"Henry-reaction"”.
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ASYMMETRIC ORGANOCATALYTIC HENRY REACTION OF β–SUBSTITUTED α-KETO ESTERS VIA DYNAMIC KINETIC RESOLUTION
… development of diastereo- and enantioselective Henry reaction of ß-substituted a-keto esters using cinchona alkaloid derived bifunctional catalyst via dynamic kinetic resolution. Chapter 1 presents a brief historical background and development of asymmetric catalysis. Particularly, the …
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Mirroring Enzymes: The Role of H-Bonding In HQuin-BAM Catalyzed Asymmetric Aza-Henry Reactions: A DFT Study into the Reactivity, Mechanism, and Origins of Selectivity
… of various organocatalytic systems in asymmetric reactions such as Henry and aza-Henry transformations is important for developing and designing new synthetic organocatalysts. The focus of this dissertation will be on the use of density functional theory (DFT) for studying the asymmetric aza-Henry …
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Synthese neuartiger Sulfoximine für die asymmetrische Metallkatalyse
… applicability in asymmetric phenyl transfer reactions onto aldehydes. Enantiomerically enriched diarylmethanols have been prepared by catalyzed asymmetric phenyl transfer reactions onto aromatic aldehydes with use of readily available beta-hydroxysulfoximines as catalysts. As the aryl source, …
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Novel Chiral Diamines and (S)-6-Chloronicotine Derivatives as Catalysts for Asymmetric Synthesis
… and amino phosphines to test in asymmetric reactions, such as the catalytic addition of diethylzinc to benzaldehyde, and palladium-catalyzed allylic alkylation. Each of these catalysts has a nitrogen containing heterocycle and is synthesized in a few steps from commercially available …
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Optimisation of chemoenzymatic processes in asymmetric synthesis
… achieved through optimisation of reaction conditions improving the synthetic utility of the biotransformations. In the first chapter a summary of literature discussing the stereochemical control of baker’s yeast (Saccharomyces Cerevisae) mediated reduction of ketones by the …
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Chirale Sulfonimidamide und Sulfoximine : Synthese, Strukturuntersuchungen und Anwendungen
… were applied in the Cu-catalyzed asymmetric Henry reaction between aromatic aldehydes and nitromethane giving products with enantiomeric excesses up to 95% ee. In the second part of this thesis the basicity of a C2-symmetric naphthaline based bissulfoximine was studied, since this compound …
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Chirale ionische Flüssigkeiten in der homogenen Katalyse
… of chiral reagents (such as catalysts) in the reaction of prochiral substrates. In this work, the use of chiral Ionic Liquids (IL = ionic liquid) as chiral reagent was investigated. The first part therefore addresses the synthesis and characterization of chiral ILs. The intention hereby was the …
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Progress Toward The Total Synthesis Of The Natural Product Herbicide Ascaulitoxin Aglycone
… blocks. Strategy 1 invokes the use of the Henry reaction as a key step for the construction of the central C4-C5 cis-aminohydroxy group, which was moderately successful, but abandoned in favor of olefination protocols. Strategy 2 invoked the Wittig reaction as a key reaction for the …
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Designing and optimizing tandem bio- and chemo-catalyzed cascade reactions to access industrially relevant chemicals in mild, aqueous conditions
… Moreover, organocatalysts provide access to reactions and mechanisms similar to enzymatic chemistries with greater stability and fewer restrictions. Taken together, organocatalysts provide a broad reactivity with substrate flexibility and a diverse product profile. These features make …
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Organokatalytische Synthesen biologisch aktiver Naturstoffe : Totalsynthesen von Amaminol A und B und (+)-Mitsugashiwalacton sowie Synthesen 2,6-disubstituierter Tetrahydropyranen
… step by an intramolecular Diels-Alder reaction of a synthesised tetraenal with an imidazolidinone-derivative as effective organocatalyst and TFA as co-catalyst. This reaction yielded the desired indane core with high selectivity, high endo/exo-selectivity and a surplus of enantiomers of …
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Organocatalytic asymmetric mannich-type reactions: an easy approach to optically active amine derivatives
… new organocatalytic protocols for Mannich-type reactions mediated by Cinchona alkaloids derivatives (Scheme I, left); the second topic, instead, regards the study of a new approach towards the enantioselective total synthesis of Aspirochlorine, a potent gliotoxin that recent studies indicate as …