Sökning: "Chiral anion"

Hittade 5 avhandlingar innehållade orden Chiral anion.

1. 1. Palladium(II)-Catalyzed Oxidative Carbocyclization : Stereoselective Formation of C–C and C–B Bonds

   Författare :Tuo Jiang; Jan-Erling Bäckvall; Ross Widenhoefer; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Carbocyclization; Palladium catalysis; Oxidation; Enallenes; Enynes; Borylation; Arylation; Asymmetric Catalysis; Chiral Brønsted acids; Chiral anion; organisk kemi; Organic Chemistry;

   Sammanfattning : Transition metal catalysis has emerged as one of the most versatile methods for the selective formation of carbon–carbon and carbon–heteroatom bonds. In particular, oxidative carbon–carbon bond forming reactions have been widely studied due to their atom economic feature. LÄS MER

3. 2. A study of the stereochemistry and electronic transitions of cyclic and acyclic thioamides by crystallography, spectroscopy and computational methods

   Författare :Knut Rang; Centrum för analys och syntes; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; UV and CD spectroscopy; rotational barriers; DNMR; X-ray; N -bis[ S -1-phenylethyl]-thiourea; N; attractive steric effect; chiral; phenyl or H- rhodanines; 3- alkyl or aralkyl -5- methyl; Conformations; electronic transitions; molecular mechanics; enantiom; Organic chemistry; Organisk kemi;

   Sammanfattning : Analysis of conformations and electron transitions of 3-(alkyl or aralkyl)-5-(methyl or phenyl)rhodanines with analogues and N,N'-bis[(S)-1-phenylethyl]-thiourea have been performed by X-ray crystallography, 1H NMR, molecular mechanics, ultraviolet spectroscopy and for the chiral rhodanines, enantiomer chromatography and circular dichroism spectroscopy. The magnitude of rotational barriers has been determined. LÄS MER

4. 3. Synthesis of Novel Homoserine Analogues - Towards t he Development of Substrate-based Peptide Inhibitors of cAMP-dependent Protein Kinase

   Författare :Anna-Carin Carlsson; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; protein kinases; protein kinase inhibitors; substrate-based kinase inhibitors; cAMP-dependent protein kinase; kemptide; homoserine; asymmetric -amino acid synthesis; glycine -anion equivalents; Schöllkopf’s bislactim ether; epoxidation; nucleophilic epoxide ring opening; microwave-assisted synthesis;

   Sammanfattning : Protein kinases are enzymes that via phosphorylation of proteins/peptides regulate most aspects of cell functions and physiology. The enzymes transfer a -phosphoryl group from ATP to hydroxyl groups of Ser, Thr and Tyr residues in their substrates. LÄS MER

5. 4. Phase separation, aggregation and gelation of a charged helixforming polysaccharide in aqueous salt solution

   Författare :Johan Borgström; Fysikalisk kemi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physical chemistry; polysaccharide; physical gel; ion binding; carrageenan; liquid crystal; polymer; Fysikalisk kemi;

   Sammanfattning : The phase behaviour and gelation of the anionic polysaccharide kappa-carrageenan (KC) in different salt solutions was studied. The specific site binding of certain anions and certain cations to the KC helix was used as a means of controlling the interactions. LÄS MER

7. 5. Ligand Dependent Regioselectivity in Palladium Mediated Allylic Alkylation

   Författare :Charlotte Johansson; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Palladium; allylic alkylation; η3-allyl palladium complexes; regioselectivity; PN-ligand; memory effects; dynamics; ligand effect; trans effects.;

   Sammanfattning : In this thesis, different aspects on ligand dependent regioselectivity in palladium mediated allylic alkylation have been studied. It is believed that the regioselectivity is a result of nucleophilic attack trans to phosphorous when applying ligands wih different donor atoms. LÄS MER