Sökning: "diastereoselectivity"

Visar resultat 1 - 5 av 20 avhandlingar innehållade ordet diastereoselectivity.

  1. 1. Synthesis and binding studies of 9,10-disubstituted anthracene and dibenzobarrelene-based receptors for recognition of carbohydrates in water

    Detta är en avhandling från Bioorganic Chemistry, Lund University

    Författare :Hans Grundberg; Lunds universitet.; Lund University.; [2004]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Organisk kemi; 2- trimethylsilyl ethyl sulfide; diastereoselectivity; water; carbohydrates; recognition; biomimetic; Artificial; receptor; Organic chemistry;

    Sammanfattning : Popular Abstract in Swedish Kolhydrater är viktiga inte bara som bränsle och strukturgivande egenskaper, vilket var uppfattningen för 25 år sedan. De ingår även som en mycket viktig del i hur celler kommunicerar med varandra. Det har de senaste åren visat sig vara kolhydrater inblandade i en mängd signalering- och igenkänningsmekanismer. LÄS MER

  2. 2. Enzymes as catalysts in synthesis of enantiomerically pure building blocks secondary alcohols bearing two vicinal stereocenters

    Detta är en avhandling från Stockholm : KTH

    Författare :Rong Liu; KTH.; [2005]
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; enzyme; kinetic resolution; enantioselectivity; lipase; diastereoselectivity; epimerisation; metal-catalysed transformation; intramolecular alkylation.; MEDICINE Chemistry; MEDICIN Kemi;

    Sammanfattning : Enzymes as tools in organic synthesis have provided enormous advantages. This thesis deals with the applications of enzymes in the kinetic resolutions of racemic compounds. The stereochemistry of chiral compounds and the kinetics of α/β hydrolase lipases are presented. LÄS MER

  3. 3. Synthesis of Tetrahydrofuran and Pyrrolidine Derivatives Utilising Radical Reactions Organochalcogenides in Reductive, Carbonylative and Group-Transfer Cyclisation

    Detta är en avhandling från Uppsala : Acta Universitatis Upsaliensis

    Författare :Cecilia Ericsson; Uppsala universitet.; [2004]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Organic chemistry; Organisk kemi; NATURAL SCIENCES Chemistry Organic chemistry; NATURVETENSKAP Kemi Organisk kemi;

    Sammanfattning : This thesis describes free-radical reactions for the construction of tetrahydrofuran and pyrrolidine derivatives. The studies are concerned with (i) diastereoselectivity in radical cyclisation, (ii) construction of tetrahydrofuran-3-ones and pyrrolidin-3-ones via radical carbonylation/cyclisation and (iii) synthesis of tetrahydrofuran derivatives via group-transfer cyclisation of organochalcogen compounds. LÄS MER

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

    Detta är en avhandling från Stockholm : Kemi

    Författare :Erik Risberg; KTH.; [2004]
    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

  5. 5. Radical Cyclization Approaches to Pyrrolidines

    Detta är en avhandling från Uppsala : Acta Universitatis Upsaliensis

    Författare :Magnus Beşev; Uppsala universitet.; [2002]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Organic chemistry; Radical cyclization; diastereselectivity; pyrrolidine; pyrroline; thiazoline; aziridine; Organisk kemi; NATURAL SCIENCES Chemistry Organic chemistry; NATURVETENSKAP Kemi Organisk kemi; organisk kemi; Organic Chemistry;

    Sammanfattning : Five-membered rings are readily prepared by 5-exo-trig radical cyclization. This thesis is concerned with novel methodology for pyrrolidine synthesis. We have synthesised selenium containing radical precursors from aziridines and α-phenylseleno ketones, and cyclized them to 2,4- and 3,4-disubstituted pyrrolidines. LÄS MER