Search for dissertations about: "asymmetric catalysis"

Showing result 21 - 25 of 91 swedish dissertations containing the words asymmetric catalysis.

  1. 21. Ruthenium-Catalyzed Asymmetric Transfer Hydrogenation

    Author : Tove Slagbrand; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; allylic alcohols; asymmetric catalysis; isomerization; reduction; ruthenium;

    Abstract : 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. READ MORE

  2. 22. Chiral Pyridine-Containing Ligands for Asymmetric Catalysis. Synthesis and Applications

    Author : Fredrik Rahm; KTH; []
    Keywords : asymmetric catalysis; chiral ligand; chiral pool; oxazoline; crown ether; ditopic receptor; bipyridine; pyridyl alcohol; modular approach; P; N-ligand; diethylzinc; allylic alkylation;

    Abstract : This thesis deals with the design and syntheses of chiral,enantiopure pyridinecontaining ligands and their applicationsin asymmetric catalyis.Chiral pyridyl pyrrolidine ligands and pyridyl oxazolineligands were synthesized and employed in thepalladium-catalysed allylic alkylation of 1,3-diphenyl-2-propenyl acetate with dimethyl malonate. READ MORE

  3. 23. Chemoenzymatic Resolution in Dynamic Systems : Screening, Classification and Asymmetric Synthesis

    Author : Yan Zhang; Olof Ramström; Sabine Flitsch; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; constitutional dynamic chemistry; dynamic systemic resolution; dynamic kinetic resolution; enzyme catalysis; transesterification; enzyme promiscuity; asymmetric synthesis; pattern recognition; self-inhibition.;

    Abstract : 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. READ MORE

  4. 24. Asymmetric transfer hydrogenation of ketones : Catalyst development and mechanistic investigation

    Author : Katrin Ahlford; Hans Adolfsson; Martin Wills; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Asymmetric catalysis; reduction; amino acid; rhodium; mechanistic investigation; kinetic study; Organic chemistry; Organisk kemi; organisk kemi; Organic Chemistry;

    Abstract : 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. READ MORE

  5. 25. Development of catalytic enantioselective C-C bond-forming and cascade transformations by merging homogeneous or heterogeneous transition metal catalysis with asymmetric aminocatalysis

    Author : Samson Afewerki; Armando Córdova; MICHELANGELO GRUTTADAURIA; Mittuniversitetet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; asymmetric catalysis; transition metals; aldehydes; heterogeneous catalysis; amino acid; organocatalysis; α-allylation; β-alkylation; dynamic transformations; polysubstituted; carbocycles; spirocyclic oxindoles; all-carbon quaternary stereocenters;

    Abstract : Chiral molecules play a central role in our daily life and in nature, for instance the different enantiomers or diastereomers of a chiral molecule may show completely different biological activity. For this reason, it is a vital goal for synthetic chemists to design selective and efficient methodologies that allow the synthesis of the desired enantiomer. READ MORE