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Filtering by: Creator Hille, Joshua D. Remove constraint Creator: Hille, Joshua D. Degree Field Chemistry Remove constraint Degree Field: Chemistry

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  • Total synthesis of (-)-7-epicylindrospermopsin

    Creator:
    Hansen, Joshua D.
    Abstract:
    The first asymmetric synthesis of (-)-7-epicylindrospermopsin via intramolecular nitrone cycloaddition is described. The synthesis utilized a convergent approach to prepare the cycloaddition precursor 176, which was assembled by condensation of hydroxylamine 175 with aldehyde 145. Hydroxylamine 175 was synthesized from ethylene glycol (166) in seven steps. Aldehyde 145 was completed...
    Resource Type:
    Dissertation
    Full Text:
    OF THE DISSERTATION OF Joshua D. Hansen for the degree of Doctor of Philosophy in Chemistry

  • Substitution Effects on the Structure and Electronic Behavior of Ternary Precious Metal Oxides

    Creator:
    Flynn, Joshua
    Abstract:
    Due to the high cost of precursor materials, complex oxides of 4d and 5d transition metals are under-studied compared to their 3d counterparts. Recent studies have shown that oxides containing heavier transition metals can exhibit exotic electronic states due to presence of strong spin-orbit coupling. The goal of this dissertation...
    Resource Type:
    Dissertation
    Full Text:
    Joshua Flynn for the degree of Doctor of Philosophy in Chemistry presented on March 7, 2017. Title

  • Synthetic studies of nonadrides

    Creator:
    Drapela, Nicholas Ernest
    Abstract:
    An asymmetric approach to the synthesis of byssochlamic acid (1) is described. Regioisomeric enzymatic differentiation is described in the selective hydrolysis of dimethyl ester 30 by porcine liver esterase. Chiral dimethyl ester 42 was prepared by desymmetrization of cyclopentene 34 using porcine liver esterase. A key intramolecular [2+2]cycloaddition-cycloreversion photometathesis of...
    Resource Type:
    Dissertation
    Full Text:
    14 1998. Title: Synthetic Studies of Nonadrides Abstract approved: James D. White An asymmetric

  • Synthesis of two subunits of avermectin B1a

    Creator:
    Dantanarayana, Anura Pathmasiri
    Abstract:
    Avermectins are a group of potent anthelmintic agents produced by Streptomyces avermitilis. They are active at extremely low dosages and are now in commercial use. In this study, the synthesis of two segments of avermectin B[subscript 1a] are described. The synthesis of the hexahydrobenzofuran subunit (segment A) began with the...
    Resource Type:
    Dissertation
    Full Text:
    approved: Redacted for privacy (it James D. White Avermectins are a group of potent anthelmintic agents

  • Studies toward the total synthesis of phorboxazole A

    Creator:
    Kuntiyong, Punlop
    Abstract:
    Studies toward the total synthesis of a highly potent cytotoxic marine natural product, phorboxazole A, were conducted and resulted in a route to an advanced intermediate, C4-C32, for this purpose. A key feature of our approach is the stereoselective synthesis of two cis-2,6-disubstituted tetrahydropyrans present in the macrolide portion of...
    Resource Type:
    Dissertation
    Full Text:
    TOTAL SYNTHESIS OF PHORBOXAZOLE A. Abstract approved: James D. White Studies toward the total

  • Synthetic studies on necic acids of pyrrolizidine alkaloids

    Creator:
    Lee, Nadine Chauyi
    Resource Type:
    Dissertation
    Full Text:
    , Joshua D. Hansen, Kurt F. Sundermann, Jungchul Kim, Younggi Choi, Sundaram M. Shanmugham, and

  • Studies towards the total synthesis of (-)-gymnodimine

    Creator:
    Wang, Guoqiang
    Abstract:
    Studies towards the total synthesis of (-)-gymnodimine (1), a marine neurotoxin with a unique molecular architecture and pronounced biological activity, are described. These studies resulted in a convergent approach to the advanced intermediate 315, containing the C3-C32 section of 1. Two synthetic routes were developed to construct the tetrahydrofuran subunit...
    Resource Type:
    Dissertation
    Full Text:
    Chow, Juris Fotins, Uwe Grether, Joshua D. Hansen, Bryan B. Hauser, David Ihie, Jungchul Kim, Eric A

  • Natural product synthesis via cyclobutanes : part I, Asymmetric synthesis of (+)-byssochlamic acid, part II, An approach to the nootropic agent huperzine A

    Creator:
    Kim, Jungchul
    Abstract:
    PART I. Asymmetric syntheses of both natural (+)- and nonnatural (-)-byssochlamic acid via a [2+2] photoaddition-cycloreversion strategy are described. X-ray crystallographic analysis of the cyclohexylamine salt 99 showed that the structure of the monomethyl ester 100 from esterase hydrolysis of 44 was originally misassigned as 56. The enantiomeric relationship of...
    Resource Type:
    Dissertation
    Full Text:
    . Robarge, Joshua D. Hansen, Kurt F. Sundermann, Sundaram M. Shanmugham, Christopher M. Lincoln, Punlop

  • Total synthesis of indole alkaloids: pt. 1. Asymmetric synthesis of (-)-ibogamine. pt. 2. An approach toward the synthesis of koumine

    Creator:
    Choi, Younggi
    Abstract:
    PART I. The preparation of (-)-ibogamine (1) in fourteen steps from benzoquinone and in 10% overall yield is a powerful illustration of the value of the asymmetric Diels-Alder reaction as a starting point in a multistep synthesis. All four cycloadducts, 70, 77, 84 and 96, obtained with the (S)-BINOL-TiCl₂ complex...
    Resource Type:
    Dissertation
    Full Text:
    Grether, Roger Hanselmann, Joshua D. Hansen, Carla Hassler, Bryan E. Hauser, Jian Hong, Peter Hrnciar

  • Studies on naphthyridinomycin biosynthesis

    Creator:
    He, Weixuan
    Resource Type:
    Dissertation
    Full Text:
    2-D NMR experiments confirmed it to be the oxazolidine ring opened product of cyanocycline A. The