Sökning: "diastereoselectivity"

Visar resultat 21 - 25 av 30 avhandlingar innehållade ordet diastereoselectivity.

1. 21. Manganese(salen) catalyzed epoxidation of alkenes

   Författare :Christian Linde; KTH; []
   Nyckelord :;

   Sammanfattning : This thesis deals the with steric and electronic effects inthe manganese(salen) catalyzed epoxidation of alkenes.Different methods were employed in the mechanisticinvestigations; molecular modelling, radical trapping, Hammettstudies on linear free-energy relationships and densityfunctional methods. LÄS MER

3. 22. Enantio- and Regioselective Iridium-Catalyzed Hydrogenation of Olefins : From Development to Total Synthesis

   Författare :Cristiana Margarita; Pher Andersson; Xavier Verdaguer; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Asymmetric hydrogenation; Iridium; Regioselectivity; Kinetic resolution; Total synthesis; organisk kemi; Organic Chemistry;

   Sammanfattning : The work presented in this thesis concerns the iridium-catalyzed asymmetric hydrogenation of cyclic olefins and allylic alcohols for the preparation of useful chiral intermediates with various substitution patterns. The strategy provides stereocontrol for both non-functionalized as well as functionalized substrates and aims to be implemented in the stereoselective preparation of chiral building blocks having more than one stereocenter. LÄS MER

4. 23. Development of new Catalytic Methods for the Selective Synthesis of Heterocycles

   Författare :Stalin Reddy Pathi Pati; Nicklas Selander; Masaharu Nakamura; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; catalysis; indium; heterocycles; Lewis acid; multicomponent reactions; furans; alkynes; organisk kemi; Organic Chemistry;

   Sammanfattning : In the field of organic chemistry, the development of new catalytic methods for the synthesis of complex molecules from simple precursors is a top priority. The main focus of this thesis concerns the diastereoselective synthesis of heterocyclic compounds using main group elements as Lewis acid catalysts. LÄS MER

5. 24. New synthetic routes to azaspiro alkaloids : Applications to the synthesis perhydrohistrionicotoxin

   Författare :Lars Hagberg; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Chemistry; Kemi; Chemistry; Kemi; organisk kemi; Organic Chemistry;

   Sammanfattning : Perhydrohistrionicotoxin, 1, is related to a family of alkaloids which display pharmacologically interesting properties. The thesis deals with development of new methods for the chemical synthesis of such alkaloids, and is divided into three parts according to the different approaches. LÄS MER

7. 25. Advances in Stereoselective Palladium(ΙΙ)-Catalyzed Oxidative Transformations of Allenes

   Författare :Daniels Posevins; Jan-Erling Bäckvall; Troels Skrydstrup; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Synthesis; Palladium Catalysis; Allenes; Biomimetic; Carbocyclization; Borylation; Carbonylation; Oxidation; Heterogeneous; organisk kemi; Organic Chemistry;

   Sammanfattning : Palladium(ΙΙ)-catalyzed carbon-carbon and carbon-heteroatom bond formation via selective C-H bond oxidation constitutes a step-economical and versatile approach towards complex target molecules. This thesis has been focused on the development of new selective palladium(ΙΙ)-catalyzed transformations of allenes under oxidative conditions catalyzed by either homogenous or heterogeneous palladium(ΙΙ) catalysts. LÄS MER