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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Preparing and Tuning the Reactivity of Palladium Carbenes and an Unusual Catalytic Isomerization of Diphenylcyclopropanes

Goll, Julie Maria 09 1900 (has links)
The preparation of palladium carbene intermediates from diphenylketene is proposed. Experiments to trap these intermediates with alkenes have been conducted and optimized, with cyclopropanes being prepared in up to 69% yield. This methodology has shown to be compatible with olefins, ethers, esters, anhydrides and various benzannulated norbornyl derivatives. In addition, an unusual palladium(II) catalyzed cyclopropane isomerization has been observed. Various substrates have undergone this isomerization affording two different olefin products in up to 61% yield. A catalytic cycle for this process is proposed.
12

NHC-catalyzed transformations: Stetter, benzoin, and ring expansion reactions

2012 June 1900 (has links)
N-Hetereocyclic carbenes (NHC) have been intensively investigated since Ukai et al had reported the first NHC-catalyzed coupling of two equivalents of benzaldehyde, to form what is known as the benzoin product. A plethora of reports have since been published on NHC-catalyzed reactions, such as the cross-benzoin, Stetter, redox reactions, and many others. An attractive feature of NHCs is their ability to effect the umpolung (inversion of reactivity) of aldehydes. The efforts in the introduction of β,γ-unsaturated-α-ketoesters as acceptors for the Stetter reaction have led to the first highly enantioselective intermolecular Stetter reaction with β-aryl substituted Stetter acceptors (up to >99% ee). The synthetic applications of the Stetter adducts generated from the α-ketoester acceptors were demonstrated to give access to a diverse number of useful building blocks. Furthermore, the α-ketoester substrates were found to also be applicable for the cross-benzoin reaction. Through the development of a new electron-deficient, morpholine-based triazolium-derived carbene, a highly chemo- and enantioselective cross-benzoin reaction was achieved using aliphatic aldehydes and α-ketoesters. This methodology constitutes as the first highly enantioselective intermolecular cross-benzoin reaction with aliphatic aldehydes (up to 93% ee). In addition, a highly divergent synthesis of Stetter adducts and cross-benzoin products could be achieved in excellent regioselectivity. Interested in utilizing NHCs as organocatalysts for the development of new reactions, tetrahydrofuran and prolinal derivatives were found to undergo efficient ring-expansions. This methodology gives access to highly functionalized lactones and lactams, which could serve as synthetically useful building blocks for the synthesis of natural products and biologically active compounds.
13

Preparing and Tuning the Reactivity of Palladium Carbenes and an Unusual Catalytic Isomerization of Diphenylcyclopropanes

Goll, Julie Maria 09 1900 (has links)
The preparation of palladium carbene intermediates from diphenylketene is proposed. Experiments to trap these intermediates with alkenes have been conducted and optimized, with cyclopropanes being prepared in up to 69% yield. This methodology has shown to be compatible with olefins, ethers, esters, anhydrides and various benzannulated norbornyl derivatives. In addition, an unusual palladium(II) catalyzed cyclopropane isomerization has been observed. Various substrates have undergone this isomerization affording two different olefin products in up to 61% yield. A catalytic cycle for this process is proposed.
14

Terthienyl carbene complexes /

Moeng, Mmushi Moses. January 2001 (has links)
Thesis (M. Sc. (Chemistry))--University of Pretoria, 2001. / Summaries in Afrikaans and English. Also available online.
15

Ylides stabilization of novel, low valent carbon-based ligands with applications in catalysis /

Asay, Matt J. January 2009 (has links)
Thesis (Ph. D.)--University of California, Riverside, 2009. / Includes abstract. Title from first page of PDF file (viewed Mar. 8, 2010). Includes bibliographical references. Issued in print and online. Available via ProQuest Digital Dissertations.
16

SYNTHESIS AND INITIAL BIOLOGICAL CHARACTERIZATION OF 10,11-METHYLENE-9- NONADECENE

Clark, James Reed, 1939- January 1971 (has links)
No description available.
17

Studies on product formation in some reactions involving methylene intermediates : Ptl Variation of formate yields in the hydrolysis of chloroform ; Pt2 The decomposition of dichlorofluoroacetic acid ; Pt3 The decomposition of chlorodifluoroacetic acid ; Pt4 Some reactions of methyl dichloromethyl ether

Duffey, Donald Creagh 08 1900 (has links)
No description available.
18

Syntheses and reactions of aminooxycarbenes from thermolysis of [Delta3]-1,3,4-oxadiazolines /

Couture, Philippe. January 1997 (has links)
Thesis (Ph.D.) -- McMaster University, 1997. / In title delta is the Greek letter with superscript 3. Includes bibliographical references. Also available via World Wide Web.
19

Synthesis and thermolysis of 2,2-dioxy-5,5-dimethyl-[delta three]-1,3,4-oxadiazolines : dioxycarbenes and their reactions /

El-Saidi, Manal M. T. January 1996 (has links)
Thesis (Ph.D.) -- McMaster University, 1996. / Includes bibliographical references (leaves [128]-135). Also available via World Wide Web.
20

Chromium and iron organometallics in organic synthesis synthetic studies toward total synthesis of taxol and chromium to iron transfer processes /

Lian, Yiqian. January 2006 (has links)
Thesis (Ph. D.)--Michigan State University. Dept. of Chemistry, 2006. / Title from PDF t.p. (viewed on June 19, 2009) Includes bibliographical references (p. 229-249). Also issued in print.

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