Search for dissertations about: "stereoselectivity"

Showing result 1 - 5 of 61 swedish dissertations containing the word stereoselectivity.

  2. 1. 1. Asymmetric aldol and alkylation reactions using pyrrolidine-based chiral auxiliaries 2. Syntheses of pine sawfly pheromone precursors and structurally related compounds

    Author : Fredrik Andersson; KTH; []
    Keywords : Chiral auxiliary; Stereoselectivity; Lewis acid; Aldol; Alkylation; Sex pheromone; Pine sawfly; Lipase; Synthesis; Diprion nipponica; Macrodiprion memoralis; Microdiprion pallipes; ;

    Abstract : This thesis describes the syntheses of the 1-propionylatedauxiliaries (S)-(− )-2-(pyrrolidin-2-yl)propan-2-ol and (S)-(− )-2-(1-methoxy-1-methylethyl)pyrrolidine andtheir use in asymmetric aldol and alkylation reactions. Thesynthesis of 1-propionylated (2S,4R) 2-{4-[(tert-butyldimethylsilyl)oxy]pyrrolidin-2-yl}propan-2-olis also described. READ MORE

  4. 2. Engineered Alcohol Dehydrogenases for Stereoselective Chemical Transformations

    Author : Thilak Reddy Enugala; Mikael Widersten; Manfred T. Reetz; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; alcohol dehydrogenase-A; biocatalysts; protein engineering; enzyme kinetics; sec-alcohols; ketones; stereoselectivity; regioselectivity; substrate selectivity and promiscuity.; Biokemi; Biochemistry;

    Abstract : Enzymes are biomolecules built from amino acids and catalyze the chemical transformations in a cell. Enzymes are by nature stereoselective, biodegradable, environmentally friendly, and can perform catalysis in aqueous solutions and at ambient temperatures. READ MORE

  5. 3. Heck Reactions with Aryl Chlorides : Studies of Regio- and Stereoselectivity

    Author : Gopal K. Datta; Mats Larhed; Anders Hallberg; Martin Oestreich; Uppsala universitet; []
    Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Heck reaction; aryl chloride; vinyl ether; regioselective; stereoselective; palladium; chelation control; microwave; Pharmaceutical chemistry; Farmaceutisk kemi;

    Abstract : Homogeneous palladium-catalyzed Heck vinylation of aryl chlorides was investigated under air using Herrmann’s palladacycle and the P(t-Bu)3-liberating salt [(t-Bu)3PH]BF4. Based on the results, controlled microwave heating was utilized to accelerate model Heck reactions with aryl chlorides down to 30 min employing an electron-poor olefin and a mixture of an ionic liquid and 1,4-dioxane as solvent. READ MORE

  6. 4. 1. Asymmetric aldol and alkylation reactions using pyrrolidine-based chiral auxiliaries 2. Syntheses of pine sawfly pheromone precursors and structurally related compounds

    Author : Fredrik Andersson; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Chiral auxiliary; Stereoselectivity; Lewis acid; Aldol; Alkylation; Sex pheromone; Pine sawfly; Lipase; Synthesis; Chemistry; Kemi;

    Abstract : .... READ MORE

  7. 5. Evolutionary Analysis and Posttranslational Chemical Modifications in Protein Redesign : A Study on Mu Class Glutathione Transferases

    Author : Ylva Ivarsson; Bengt Mannervik; Gun Stenberg; Richard N. Armstrong; Uppsala universitet; []
    Keywords : Biochemistry; glutathione transferase; evolutionary analysis; positive selection; epoxide; stereoselectivity; protein modification; Biokemi;

    Abstract : Glutathione transferases (GSTs) constitute a family of multifarious enzymes that conjugate glutathione (GSH) with a wide range of electrophiles. GSTs are grouped into different classes based on protein sequence similarities. Despite high sequence identities between GSTs of the same class they often display different substrate specificites. READ MORE