Sökning: "enantioselective reactions"

Visar resultat 1 - 5 av 42 avhandlingar innehållade orden enantioselective reactions.

  1. 1. Quantum Chemical Studies of Enantioselective Organocatalytic Reactions

    Författare :Peter Hammar; Fahmi Himo; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; DFT; enantioselective; asymmetric; organocatalysis; Theoretical chemistry; Teoretisk kemi;

    Sammanfattning : Density Functional Theory is used in order to shed light on the reaction mechanisms and the origins of stereoselectivity in enantioselective organocatalytic reactions. The reactions investigated are the dipeptide-catalyzed aldol reaction, the cinchona thiourea-catalyzed nitroaldol reaction and the prolinol derivative-catalyzed hydrophosphination reaction. LÄS MER

  3. 2. Organocatalytic Domino Reactions

    Författare :Henrik Sundén; Armando Córdova; Pavel Kočovský; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; organocatalytic; domino; iminium-enamine; enamine-iminium; Organic chemistry; Organisk kemi; Organic Chemistry; organisk kemi;

    Sammanfattning : Organocatalyzed reactions involving activation strategies of ketones and aldehydes are important processes in organic chemistry. These activation strategies serve as a versatile platform for the construction of several domino reactions. LÄS MER

  4. 3. Catalytic Regio- and Stereoselective Reactions for the Synthesis of Allylic and Homoallylic Compounds

    Författare :Rauful Alam; Kalman Szabo; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; palladium catalysis; C−H functionalization; boronic acid; allylboration; asymmetric catalysis; allylic; homoallylic; diastereoselective; enantioselective; organisk kemi; Organic Chemistry;

    Sammanfattning : This thesis is focused on two main areas of organic synthesis, palladium-catalyzed functionalization of alkenes and allylic alcohols, as well as development of new allylboration reactions.We have developed a palladium-catalyzed selective allylic trifluoroacetoxylation reaction based on C−H functionalization. LÄS MER

  5. 4. Lewis acid Mediated Aza-Diels-Alder Reactions and Asymmetric Alkylations of 2H-azirines

    Författare :Erik Risberg; KTH; []
    Nyckelord :Enantioselective; diastereoselective; vinyl azide; 2H-azirines; aziridines; Lewis acid; chiral ligand; chiral auxiliary organolithiums Diels-Alder reaction alkyl radicals triethylborane.;

    Sammanfattning : This thesis describes the use of 2H-azirines, three-membered unsaturatednitrogen-containing heterocycles, as reactive intermediates ina number of Lewis acid promoted alkylations and Diels-Alderreactions providing synthetically useful aziridines. In order to carry out this investigation a new generalprocedure for the ring closure of vinyl azides, forming theresultant 3-substituted-2H-azirines, was developed applying low boiling solventsin closed reaction vessels at elevated temperatures. LÄS MER

  7. 5. Breaking the symmetry: creation and transfer of optical activity via total spontaneous resolution and stereoselective reactions

    Författare :Susanne Olsson; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; absolute asymmetric synthesis; enantioselective reactions; chirality; spontaneous resolution; conglomerate; organometallic chemistry; coordination compounds; attritionenhanced deracemisation; polymorphism; organolithium compounds; single-crystal X-ray crystallography;

    Sammanfattning : The generation of optical activity from achiral or racemic precursors – absolute asymmetric synthesis – is discussed in relation to the origin of biomolecular homochirality but is also often (incorrectly) regarded as being impossible. One approach to absolute asymmetric synthesis is the use of compounds that form chiral crystals. LÄS MER