Sökning: "asymmetric catalysis"

Visar resultat 11 - 15 av 91 avhandlingar innehållade orden asymmetric catalysis.

  1. 11. Impact of Secondary Interactions in Asymmetric Catalysis

    Författare :Anders Frölander; Christina Moberg; Gerard van Koten; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; asymmetric catalysis; secondary interaction; hydrogen bond; chiral ligand; allylic alkylation; hydrosilylation; cyanation; pymox; box; PHOX; pybox; palladium; iridium; rhodium; Lewis acid; Lewis base; Organic chemistry; Organisk kemi;

    Sammanfattning : This thesis deals with secondary interactions in asymmetric catalysis and their impact on the outcome of catalytic reactions. The first part revolves around the metal-catalyzed asymmetric allylic alkylation reaction and how interactions within the catalyst affect the stereochemistry. LÄS MER

  2. 12. Asymmetric Hydrogenations of Imines, Vinyl Fluorides, Enol Phosphinates and Other Alkenes Using N,P-Ligated Iridium Complexes

    Författare :Jarle Sidney Diesen; Pher G. Andersson; Kálmán J. Szabó; Uppsala universitet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Organic chemistry; Catalysis; Asymmetric; Hydrogenations; Reductions; Alkenes; Imines; Vinyl fluorides; Enolphosphinates; Transition metal; Complexes; Iridium; Organisk kemi; Chemistry; Kemi;

    Sammanfattning : The research described in this thesis is directed toward the efficient, enantioselective synthesis of chiral products that have useful functionality. This goal was pursued through catalytic asymmetric hydrogenation, a reaction class that selectively introduces one or two stereocenters into a molecule in an atom-efficient step. LÄS MER

  3. 13. Development and application of new chiral -amino alcohols in synthesis and catalysis : Use of 2-azanorboryl-3-methanols as common intermediates in synthesis and catalysis

    Författare :Pedro Pinho; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Chemistry; Asymmetric synthesis; hetero-Diels-Alder reactions; chiral cyclopentyl-amines; chiral ligands and catalysts; amino alcohols; asymmetric reductions; ruthenium transfer hydrogenation; oxazaborolidines; asymmetric additions; dialkylzinc reagents; Kemi; Chemistry; Kemi; organisk kemi; Organic Chemistry;

    Sammanfattning : The development and application of unnatural amino alcohols,prepared via hetero-Diels-Alder reactions,in synthesis and catalysis is described.The studies are concerned with the [i]scope of the hetero-Diels-Alder reaction and preparation of important intermediates in the synthesis of antiviral agents,[ii ]application of amino alcohols in the ruthenium transfer hydrogenation of ketones,[iii ]use of similar precursors in the in situ generation of oxazaborolidines for reduction of ketones,and [iv] development and application of new chiral auxiliaries for dialkylzinc additions to activated imines, respectively. LÄS MER

  4. 14. Self-adaptable catalysts : Importance of flexibility and applications in asymmetric catalysis

    Författare :Ester Fjellander; Christina Moberg; Jay Siegel; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; adaptable; flexible; semi-flexible; symmetry; conformational study; mechanistic study; rotation barrier; VT NMR; asymmetric catalysis; ligand design; allylic alkylation; hydrogenation; azepines; dioxaphosphepines; phosphepines; amines; phosphines; phosphoramidites; phosphinites; palladium; rhodium; Organic chemistry; Organisk kemi;

    Sammanfattning : The topic of this thesis is the design and synthesis of biaryl-based self adaptableligands for asymmetric metal catalysis. The results discussed in papers I-III are covered, together with some unpublished results concerning substrate-adaptable catalysts. A general survey of self-adaptable catalysts is presented first. LÄS MER

  5. 15. Synthesis and evaluation of bicyclic 1,3-diols (BODOLs) as ligands for asymmetric catalysis

    Författare :Ian Sarvary; Centrum för analys och syntes; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Organisk kemi; Organic chemistry; yeast reductions; supramolecular chemistry; diethylzinc; computation; structure of Ti-diolates; diol ligands; titanates; asymmetric catalysis; asymmetric synthesis;

    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