Sökning: "C-C bond formation"

Visar resultat 6 - 10 av 14 avhandlingar innehållade orden C-C bond formation.

1. 6. Olefins from carbonyls : Development of new phosphorus-based cross-coupling reactions

   Författare :Nicolas Daniele D'Imperio; Sascha Ott; Carlos Romero-Nieto; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; olefins; carbonyl olefination; phosphaalkenes; stereoselective synthesis; Wittig; Horner-Wadsworth-Emmons; McMurry;

   Sammanfattning : Olefins, compounds containing C=C double bonds, are omnipresent in nature and serve as useful starting materials for various chemical modifications. Olefins are of crucial importance in Medicinal Chemistry and are also present in essential objects like dyes, polymers and plastics. LÄS MER

3. 7. Micro-reaction Mechanism Study of the Biomass Thermal Conversion Process using Density Functional Theory

   Författare :Xiaolei Zhang; Weihong Yang; Linda J. Broadbelt; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; biomass thermal conversion; cellulose pyrolysis; char steam gasification; adsorption; interaction; mechanism; quantum chemistry; density functional theory;

   Sammanfattning : Biomass, or bio-energy, is one of the most important alternative energies because of environmental concerns and the future shortage of fossil fuels. Multi-scaled bioenergy studies have been performed in the division of Energy and Furnace Technology, which included studies of macroscopic systems such as systems and reactors, modeling of computational fluid dynamics (CFD), and atomic/molecular level studies. LÄS MER

4. 8. Quantum Chemical Modelling of Enzymatic and Organometallic Reactions

   Författare :Ferran Planas; Fahmi Himo; Edina Rosta; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; DFT; enzyme; organometallic; mechanisms; organisk kemi; Organic Chemistry;

   Sammanfattning : In this thesis, density functional theory (DFT) is employed in the study of two enzymes and two organometallic systems.First, the natural reaction mechanism, as well as the enantioselective formation of α-hydroxyketones catalysed by two thiamine diphosphate (ThDP)- dependent enzymes, namely benzoylformate decarboxylase (BFDC) and 2-succinyl-5-enolpyruvyl-6-hydroxy-3-cyclohexene-1-carboxylic-acid (SEPHCHC)- synthase (MenD), are investigated. LÄS MER

5. 9. Structural biology of carbohydrate transfer and modification in natural product biosynthesis

   Författare :Magnus Claesson; Karolinska Institutet; Karolinska Institutet; []
   Nyckelord :;

   Sammanfattning : Certain organisms, can during periods of limited resources, adapt their metabolism to enable biosynthesis of secondary metabolites, compounds that increase competitiveness and chances of survival. The subjects of this thesis are enzymes acting on carbohydrate substrates during secondary metabolism. LÄS MER

7. 10. Theoretical Studies of Natural Gas Hydrates and H-bonded Clusters and Crystals

   Författare :Yuan Liu; Lars Ojamäe; Per-Olov Käll; Ben Slater; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : In this thesis H-bonded systems (natural gas hydrates, water clusters, and crystal ice) are studied by density functional theory (DFT) computations.Natural gas hydrates (NGHs) play an important role in energy and environmental fields: NGHs are considered as a promising backup energy resource in the near-future due to their tremendous carbon content; improper exploration of NGHs could induce geological disasters and aggravate the greenhouse effect. LÄS MER