Sökning: "substitution reaction"

Visar resultat 21 - 25 av 127 avhandlingar innehållade orden substitution reaction.

1. 21. Methods for Asymmetric Olefination Reactions; Development and Application to Natural Product Synthesis

   Författare :Daniel Strand; Tobias Rein; Viresh Rawal; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Antitumor agents; Asymmetric Horner-Wadsworth-Emmons; Desymmetrization; Metal-catalyzed olefination; Mucocin; Palladium-catalyzed allylic substitution; Parallel kinetic resolution; Pyranicin; Pyragonicin; Rhenium; Stereoconvergent synthesis; Stereodivergent synthesis; Stereoselective synthesis; Tetrahydropyran; Wittig reaction; Organic chemistry; Organisk kemi;

   Sammanfattning : This thesis deals with the development and application of methods for asymmetric olefinations, in particular Horner-Wadsworth-Emmons (HWE) reactions, in the synthesis of certain natural products. Relying on asymmetric HWE reactions to access key building blocks, two natu-ral products, pyranicin and pyragonicin, were synthesized from common late intermediates. LÄS MER

3. 22. Palladium-catalyzed aromatic coupling and allylic substitution

   Författare :Helena Hagelin; KTH; []
   Nyckelord :;

   Sammanfattning : Different types of palladium(II)-catalyzed aromatic couplingreactions have been investigated.The cyclization of diphenyl ether was found to be moresensitive to reaction conditions than was the cyclization ofthe diphenylamine derivatives. LÄS MER

4. 23. Quantum Chemical Studies of Aromatic Substitution Reactions

   Författare :Magnus Liljenberg; Tore Brinck; Leif Eriksson; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Teoretisk kemi och biologi; Theoretical Chemistry and Biology;

   Sammanfattning : In this thesis, density functional theory (DFT) is used to investigate the mechanisms and reactivities of electrophilic and nucleophilic aromatic substitution reactions (SEAr and SNAr respectively). For SEAr, the σ-complex intermediate is preceded by one (halogenation) or two (nitration) π-complex intermediates. LÄS MER

5. 24. Perfluroaryl azides : Reactivities, Unique Reactions and their Applications in the Synthesis of Theranostic Agents

   Författare :Sheng Xie; Mingdi Yan; Olof Ramström; Stefan Bräse; KTH; []
   Nyckelord :Click Chemistry; Dipolar Cycloaddition; Enamine; Triazoline; Amidine; Aggregation-induced emission; pure nanodrugs; aryl amide; thioacid azide reaction; nucleophilic aromatic substitution; azide-masked fluorophore; nitrene insertion; Kemi; Chemistry;

   Sammanfattning : The work centersaround perfluoroaryl azides (PFAAs), and theirability to undergo certain fast and robusttransformations. The chemistry was furtherappliedfor biomedical applications.The first section focuses on the azide-aldehyde-amine cycloaddition using PFAAs. LÄS MER

7. 25. Organic Reactions i Organised Media

   Författare :TOMASZ WITULA; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; nucleophilic substitution; mesoporous material; microemulsion; silica; lipase; Liquid crystal; alumina; entrapment.; heterogenized; titania; organic synthesis;

   Sammanfattning : A common problem in synthetic organic chemistry is reactant incompatibility between lipophilic organic compounds and inorganic salts. The thesis reports an investigation of some organic reactions, involving incompatible substrate and nucleophile, performed in liquid crystalline phases and also in slurries of mesoporous materials with different symmetry. LÄS MER