Sökning: "asymmetric"
Visar resultat 11 - 15 av 703 avhandlingar innehållade ordet asymmetric.
11. 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
12. Ruthenium-Catalyzed Asymmetric Transfer Hydrogenation
Sammanfattning : This thesis covers the development of two new methods for the asymmetric reduction of ketones and ketone intermediates. The protocols developed are based on the use of a ruthenium pseudo-dipeptide catalyst that previously has been shown to be efficient and selective in the asymmetric reduction of carbonyl compounds. LÄS MER
13. Catalytic Asymmetric Ketone and Alkene Reductions Using Transition Metal Complexes
Sammanfattning : This thesis contains seven papers dealing with iridium and ruthenium based catalytic asymmetric reductions, either of ketones into chiral alcohols, or olefins into chiral alkanes. The first part of the thesis describes how we have designed and evaluated new bicyclic ligands containing either N,S or N,N chelating atoms. LÄS MER
14. Chemoenzymatic Resolution in Dynamic Systems : Screening, Classification and Asymmetric Synthesis
Sammanfattning : This thesis is divided into four parts, all centered around Constitutional Dynamic Chemistry (CDC) and Dynamic Kinetic Resolution (DKR) using biocatalysts for selective transformations, and their applications in screening of bioactive compounds, organic synthesis, and enzyme classification. In part one, an introduction to CDC and DKR is presented, illustrating the basic concepts, practical considerations and potential applications of such dynamic systems, thus providing the background information for the studies in the following chapters. LÄS MER
15. Asymmetric transfer hydrogenation of ketones : Catalyst development and mechanistic investigation
Sammanfattning : The development of ligands derived from natural amino acids for asymmetric transfer hydrogenation (ATH) of prochiral ketones is described herein. In the first part, reductions performed in alcoholic media are examined, where it is found that amino acid-derived hydroxamic acids and thioamides, respectively, are simple and versatile ligands that in combination with [RhCp*Cl2]2 efficiently catalyze this particular transformation. LÄS MER
