Sökning: "asymmetric hydrogenation"
Visar resultat 21 - 25 av 59 avhandlingar innehållade orden asymmetric hydrogenation.
21. 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
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
22. New Methods for the Synthesis of Vicinal Stereocenters : Palladium-Catalyzed Domino Reactions and Asymmetric Transfer Hydrogenation
Sammanfattning : In this thesis the synthesis of vicinal stereocenters is investigated in two distinct contexts, namely the construction of 3,3-disubstituted oxindoles and the synthesis of b-hydroxy-a-amino acids. Both scaffolds are prevalent in a range of natural products and biologically relevant compounds and, therefore, methods for their synthesis are of great import. LÄS MER
23. Asymmetric Synthesis of C-Glycosylated Amino Acids : Incorporation in Collagen Glycopeptides and Evaluation in a Model for Rheumatoid Arthritis
Sammanfattning : This thesis describes stereoselective syntheses of four amino acids, three of which are C-glycosidic analogues of glycosylated amino acids. The overall goal of the project was to probe the interactions between MHC molecules, glycopeptide antigens and T cell receptors, that are essential for development of collagen induced arthritis. LÄS MER
24. Enantio- and Regioselective Iridium-Catalyzed Hydrogenation of Olefins : From Development to Total Synthesis
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
25. Asymmetric Hydrogenations using N, P - Ligated Iridium Complexes
Sammanfattning : The research described in this thesis focuses on the catalytic asymmetric hydrogenation of prochiral olefins using N, P – chelated iridium catalysts. This catalytic system is tolerant to a wide range of substrates and performs better than the well-known ruthenium- and rhodium-catalytic systems for substrates devoid of coordinating groups in proximity of the olefin. LÄS MER