Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 69 for “"asymmetric catalysis"”.
-
Asymmetric Catalysis in Polymersome Nanoreactors
Contains fulltext : 140662.pdf (Publisher’s version ) (Open Access)
-
Fundamental and Applied Studies in Asymmetric Catalysis
… were synthesized as templates for asymmetric catalytic reactions that could involve substrate precoordination to a Lewis acidic site remote from the transition metal reaction site. Primary amines were found to bind reversibly via a nitrogen-boron interaction to the free ligands L*. …
-
Metal based asymmetric catalysis in Baeyer-Villiger oxidations
… combinations were observed. Moreover, a new asymmetric variant of the Baeyer-Villiger rearrangement was devised. The combination of enantiopure BINOL and properly chosen magnesium reagents gave rise to species that were able to mediate the oxidation of prochiral cyclobutanones to the …
-
Asymmetric Catalysis with Brønsted Acids: Experiments and Calculations
… described herein focuses on enantioselective catalysis using BINOL-based Brønsted acids. The initial part of this work comprises the development of chiral phosphoric acids and N-triflylphosphoramides having alternative groups at the 3,3’- positions, different from the widely common aryl …
-
Applications of planar-chiral heterocycles in asymmetric catalysis
The development of planar-chiral heterocycles for asymmetric catalysis and their applications to enantioselective processes were investigated. Reactions including the kinetic resolution of propargylic alcohols, the enantioselective ring opening of meso epoxides, and the asymmetric hydrosilylation …
-
Novel Metal Amido-Complexes – Syntheses, Reactivity and Asymmetric Catalysis
… high selectivities and good activities in the asymmetric hydrogenation of ketones, the development of amido-complex catalysts for the enantioselective hydrogenation of imines represents a major focus of this work. A library of novel amines 4 was synthesized by deprotonation of the hydroxyl …
-
Synthesis and application of pinene-pyridine derivatives in asymmetric catalysis
… derivatives, and their application in asymmetric catalysis. Both transition metal catalysed and organocatalytic transformations were investigated. Chiral pyridine-phosphines based on α-pinene were synthesised and applied as efficient P,N-ligands for the enantioselective …
-
Synthesis of Functionalised Cobalt Sandwich Complexes for Application in Asymmetric Catalysis
The reaction of cobalt sandwich complex (η5-(N,N-dimethylaminomethyl)cyclopentadienyl)(η4-tetraphenylcyclobutadiene)cobalt with sodium tetrachloropalladate and N-acetyl-D-phenylalanine gave planar chiral palladacycle …
-
Novel Enantiopure ß-Amino Alcohols and ß-Amino Thiols in Asymmetric Catalysis
… in organic chemistry, this work concentrated on asymmetric catalysis. Moreover, a major focus was on asymmetric organocatalysis as there have been tremendous successes in this field during the last years. This is in accordance with the current trends in the modern chemical research, which is …
-
Design, synthesis and mechanistic studies of boron and phosphorus heterocycles and their applications in asymmetric catalysis
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1999.
-
Studies in Asymmetric Catalysis: Lewis Base catalyzed/Lewis Acid Mediated Aldol Reactions of Ketone- and Amide Derived Nucleophiles
Additionally, the use of the silicon tetrachloride---chiral phosphoramide system has proven a competent catalyst for highly selective vinylogous aldol reactions between dienolates derived from a variety of alpha,beta-unsaturated carbonyl compounds to aldehydes. These reactions provided high levels …
-
Studies in Asymmetric Catalysis. Part I. Lewis Base-Catalyzed Aldol Additions. Part II. Bis(oxazoline)palladium(ii)-Catalyzed Cyclopropanation
A variety of bis(oxazoline)palladium(II) complexes were prepared and tested in the cyclopropanation of ethyl (E)-cinnamate with diazomethane. Although an enantioselective process was never realized, effects of substitution on the ligand, catalyst loading studies, and other investigations led to a …
-
Studies in Asymmetric Catalysis: Lewis Base Catalyzed, Enantioselective Addition of Trimethylsilyl Cyanide, Trimethylsilyltrifluoromethane, and Glycolate-Derived Silyl Ketene Acetals to Aldehydes
A catalytic system involving silicon tetrachloride and a chiral, Lewis basic bisphosphoramide catalyst is effective for the addition of glycolate-derived silyl ketene acetals to aldehydes. The sense of diastereoselectivty could be modulated by changing the size of the substituents on the silyl …
-
Applications of planar-chiral phosphaferrocene-oxazolines in asymmetric catalysis and enantioselective desymmetrization by carbon nucleophiles in the presence of chiral ligands
… applied to several transition metal-catalyzed asymmetric reactions. In Pd-catalyzed asymmetric allylic alkylations, it is established that the planar chirality of the phosphaferrocene, not the central chirality of the oxazoline subunit, is the dominant stereocontrol element. On the other hand, …
-
The origin of remarkable chromatographic differences in novel azulenyl-1,5-diols and synthesis and use of phosphinine and phosphabarrelene ligands for asymmetric catalysis.
… but have shown promise as good ligands for asymmetric catalysis. Our group had previously synthesized a C₂-symmetric chiral bis-camphorphosphinine and the derived bis-camphorphosphabarrelene but neither had been tested as ligands for hydroformylation. In this work, optimization of the …
-
Synthese von planar chiralen Imidazoliumsalzen, ihren Metall-Carbenkomplexen und deren Verwendung in der asymmetrischen Katalyse
… chirality plays a significant role in many asymmetric catalytic processes. The concept of planar chirality is often implemented by the application of metallocenes such as ferrocene derivatives. Some industrially important syntheses are amongst those processes, including the preparation of …
-
Chirale Phosphortriamide und Phosphin-Phosphoramidite als Liganden für die asymmetrische Katalyse
Asymmetric catalysis with transition metal complexes containing chiral ligands is an efficient tool for the synthesis of enantioenriched compounds, which can be used as active pharmaceutical ingredients, agrochemicals, flavors or fragrances. The development of novel chiral ligands plays a major …
Page 1 of 4