Sökning: "enantioselective"
Visar resultat 1 - 5 av 111 avhandlingar innehållade ordet enantioselective.
1. Quantum Chemical Studies of Enantioselective Organocatalytic Reactions
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
2. Chemo- and Enantioselective Hydrogenations : The Struggle of Expanding the Substrate Scope of Iridium Catalyzed Asymmetric Hydrogenations of Olefins
Sammanfattning : The asymmetric hydrogenation of olefins is a facile and popular method of reaching chiral products. Whereas ruthenium- and rhodium-catalyzed asymmetric hydrogenations have a long history, the use of iridium in this area is new but fast-growing. LÄS MER
3. Chiral building blocks for synthesis of pine sawfly sex pheromones Enantioselective Lipase Catalysed Acylations and Esterifications of Primary Alcohols and Acids and Synthesis of the Sex Pheromone of the Pine Sawfly Microdiprion pallipes
Sammanfattning : This thesis describes the development of new methods for thepreparation of enantiomerically pure methyl branched alkylcompounds and their use as building blocks in the synthesis ofstereoisomerically pure pheromones of pine sawflies.The high regioselectivity, enantioselectivity and activityof lipases in organic solvent in conjunction withenvironmentally compatible reaction conditions have madelipase-catalysed synthesis an attractive alternative toconventional synthetic methods in organic chemistry. LÄS MER
4. Lewis acid Mediated Aza-Diels-Alder Reactions and Asymmetric Alkylations of 2H-azirines
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. Bispyridylamides as ligands in asymmetric catalysis
Sammanfattning : This thesis deals with the preparation and use of chiralbispyridylamides as ligands in metal-catalyzed asymmetricreactions. The compounds were prepared by amide formation usingdifferent coupling reagents. LÄS MER
