Sökning: "bond cleavage"

Visar resultat 1 - 5 av 56 avhandlingar innehållade orden bond cleavage.

  1. 1. Lewis acid promoted endocyclic cleavage of glycosides and related acetals

    Författare :Roger Olsson; Centrum för analys och syntes; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; halichomycin; allylation; carbene; hydrogen bond; organozinc; organotitanium; furanosides; organoaluminium; pyranosides; glycosides; stereoselective; endocyclic cleavage; nucleophilic ring opening; ab initio; Organic chemistry; Organisk kemi;

    Sammanfattning : This thesis is a summary of five papers concerning endocyclic cleavage of glycosides and related acetals. Simple lactol ethers undergo endocyclic cleavage to give acyclic chain extended products on treatment with organoaluminium and organotitanium reagents. LÄS MER

  3. 2. Cleavage Specificity of Mast Cell Chymases

    Författare :Mattias K. Andersson; Lars Hellman; Gunnar Pejler; Per Venge; Uppsala universitet; []
    Nyckelord :Biology; Immunology; Mast cell; Serine protease; Chymase; Cleavage specificity; Phage display; Biologi;

    Sammanfattning : Mast cells (MC) are potent inflammatory cells that are known primarily for their prominent role in IgE mediated allergies. However, they also provide beneficial functions to the host, e.g. in bacterial and parasitic defence. LÄS MER

  4. 3. Samarium(II)-mediated Reactions in Organic Synthesis - Method Development and Mechanistic Investigation

    Författare :Tobias Ankner; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Samarium II iodide; reduction; single electron transfer; nitro group reduction; mechanistic study; bond cleavage; deoxygenation; additives; toluenesulfonyl deprotection; defluorination.;

    Sammanfattning : This thesis describes the development of methods using divalent samarium reagents in organic synthesis. The main focus is placed on functional group reductions, but reductive formation of carbon-carbon bonds has also been investigated. LÄS MER

  5. 4. Lanthanide-mediated C-F Bond Activation Method Development and Mechanistic Investigation

    Författare :Mario Janjetovic; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; C-F bond activation; fluorine chemistry; lanthanides; single-electron transfer reagent; Lewis acid; chemoselectivity; synthetic method; catalysis;

    Sammanfattning : The use of transition-metals and main-group Lewis acids has proven to be an outstanding source for activation and subsequent functionalization of fluorinated compounds. However, the first is mainly limited to C(sp2)–F bonds which partially are activated by an adjacent heteroatom, and the latter is limited to simple C(sp3)–F bonds due to particularly strong Lewis acid character. LÄS MER

  7. 5. Biomimetic Transition Metal Catalysts : Insights from Theoretical Modeling

    Författare :Adam Johannes Johansson; Per E. M. Siegbahn; Margareta R. A. Blomberg; Per-Ola Norrby; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Catalysis; biomimetic; copper; non-heme iron; heme iron; O2 cleavage; H-atom transfer; radical chemistry; redox chemistry; thermo chemistry; entropy calculations; quantum chemistry; spin states; density functional theory DFT ; self-interaction error SIE .; Chemical physics; Kemisk fysik; kemisk fysik; Chemical Physics;

    Sammanfattning : The scientific interest in the chemistry of synthetic transition metal complexes is motivated by at least two arguments:1.These can be regarded as models of biological transition metal complexes, e.g. metalloenzymes, whose functions can be difficult to reveal in detail due to their complexity. LÄS MER