Sökning: "asymmetric synthesis"
Visar resultat 16 - 20 av 159 avhandlingar innehållade orden asymmetric synthesis.
16. Reaction Between Grignard reagents and Heterocyclic N-oxides : Synthesis of Substituted Pyridines, Piperidines and Piperazines
Sammanfattning : This thesis describes the development of new synthetic methodologies for preparation of bioactive interesting compounds, e.g. substituted pyridines, piperidines or piparazines. Thesecompounds are synthesized from commercially available, cheap and easily prepared reagents, videlicet the reaction between Grignard reagents and heterocyclic N-oxides. LÄS MER
17. Synthesis and evaluation of bicyclic 1,3-diols (BODOLs) as ligands for asymmetric catalysis
Sammanfattning : Several ligands based upon 2-substituted bicyclic[2.2.2]octane-2,6-diols (BODOLs) were synthesized and evaluated in two catalytic reactions: I) the Ti(IV)-mediated catecholborane asymmetric reduction of prochiral ketones and II) as catalysts in the asymmetric addition of diethylzinc to aromatic aldehydes. LÄS MER
18. Cluster-Based Catalysts for Asymmetric Synthesis
Sammanfattning : In this work, the synthesis and characterisation of new low-valence transition metal carbonyl clusters, and an investigation into their viability to act as catalysts/catalyst precursors in asymmetric synthesis, are described. Carbonyl clusters based on ruthenium and osmium have been tested as (pre)catalysts for asymmetric hydrogenation of alpha-unsaturated carboxylic acids, and cobalt carbonyl clusters have been used as (pre)catalysts in (asymmetric) Pauson-Khand synthesis. LÄS MER
19. Development of organocatalytic asymmetric transformations
Sammanfattning : The ability of amino acids and amino acid derivatives to mediate various organocatalytic asymmetric transformations has been investigated and applied in the development of various reactions. This work describes the development of a direct catalytic asymmetric α-aminomethylation of ketones and aldehydes, a catalytic asymmetric aziridination, hydrophosphination and amination of α,β-unsaturated aldehydes. LÄS MER
20. Enantio- and Regioselective Iridium-Catalyzed Hydrogenation of Olefins : From Development to Total Synthesis
Sammanfattning : The work presented in this thesis concerns the iridium-catalyzed asymmetric hydrogenation of cyclic olefins and allylic alcohols for the preparation of useful chiral intermediates with various substitution patterns. The strategy provides stereocontrol for both non-functionalized as well as functionalized substrates and aims to be implemented in the stereoselective preparation of chiral building blocks having more than one stereocenter. LÄS MER
