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Filtering by: Creator Holroyd, Michael H. Remove constraint Creator: Holroyd, Michael H. Advisor White, James D. Remove constraint Advisor: White, James D.

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  • The synthesis of trisporic acids

    Creator:
    Prisbylla, Michael Paul
    Abstract:
    A total synthesis of the fungal hormones, trisporic acids A and B, is described, starting from a -methyltetronic acid 34. A Robinson annelation of 34 with ethyl vinyl ketone affords the lactone 33. Treatment of 33 with N-bromosuccinimide gave 97, which was hydrolyzed to the lactol 103. The reaction of...
    Resource Type:
    Dissertation
    Full Text:
    THESIS OF Michael Paul Prisbylla for the degree of Doctor of Philosophy in Chemistry presented on July

  • 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:
    methoxypyridine system via an azadiene Diels- Alder reaction were unsuccessful. However, intramolecular Michael

  • Cis-2,5-diaminobicyclo[2.2.2]octane : a novel C₂-symmetric scaffold for asymmetric catalysis

    Creator:
    Shaw, Subrata
    Abstract:
    This thesis describes the development of a new enantioselective synthetic method employing chiral cis-2,5-diaminobicyclo[2.2.2]octane-based organometallic catalysts. The significance of this new method to organic synthesis is illustrated with preparation of enantioenriched products that are transformed to important pharmaceutical agents. Chapter 1 provides a brief historical overview of asymmetric catalysis, especially...
    Resource Type:
    Dissertation
    Full Text:
    sulfa-Michael addition (SMA) of thiols to acyclic a,(3- unsaturated ketones. I3-Thiaketones are

  • 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:
    missing. There is also a change in the keto-enol status of the uracil moiety. 4 H H o Ny~H NyNH H

  • Studies toward the total synthesis of (+)-providencin

    Creator:
    Jana, Somnath
    Abstract:
    Studies toward the total synthesis of (+)-providencin (1), a highly oxygenated cembranoid dipterpene with a unique bicyclo[12.2.0]hexadecane skeleton and pronounced biological activity, are described. These studies resulted in the synthesis of advanced intermediates 320 and 332 which contain all of the carbon atoms of 1. In a first generation approach...
    Resource Type:
    Dissertation
    Full Text:
    to couple the two major fragments, 228 and 288, using palladium-catalyzed C-H activation of the

  • Approaches toward the asymmetric synthesis of pillaromycin A

    Creator:
    Nolen, Ernest G.
    Resource Type:
    Dissertation
    Full Text:
    States of the Intramolecular Diels-Alder Reaction. 29 8. Two-Dimensional 1 H NMR Spectroscopy (COSY

  • Synthetic studies on alkaloids : part I, an approach toward the synthesis of (̳+)-koumine : part II, an approach toward the synthesis of (̳+)-morphine

    Creator:
    Stappenbeck, Frank
    Resource Type:
    Dissertation
    Full Text:
    approach entails a projected intramolecular Michael addition of the butenolide 96. The second route

  • Phenolic oxidative coupling : an approach to the synthesis of pretazettine

    Creator:
    Chong, Wesley Kwan Mung
    Abstract:
    Various hypervalent iodine compounds were evaluated as reagents for intramolecular phenolic oxidative coupling. It was found that phenyliodine(III) bis(trifluoroacetate) was effective for the coupling of the monophenolic substrate 13a to 14a under neutral conditions. Vanadium oxytrifluoride and hypervalent iodine compounds were compared as oxidants for the conversion of 32 to...
    Resource Type:
    Dissertation
    Full Text:
    predominance of intermediate 3 was shown after a spontaneous internal Michael addition led to Pummerer's

  • 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:
    Schwartz, Sundaram M. Shanmugham, Helmars Smits, Kurt F. Sundermann, Miroslav Terinek, Michael Thutewohi

  • Synthetic transformations of shikimic acid

    Creator:
    White, Edward D., III
    Abstract:
    Four strategies which involve synthetic elaboration of the shikimate nucleus are discussed. Methyl shikimate was differentially protected as the 3,4-0-cyclopentylidene ketal and as the 5- 0- tert- butyldiphenylsilyl ether. The methyl ester was then reduced with diisobutylaluminum hydride and the resulting allylic alcohol was oxidized to aldehyde 47 with pyridinium...
    Resource Type:
    Masters Thesis
    Full Text:
    CO2H Prephenic Acid Chorismic Acid CO2H NH2 Anthranilic Acid R = OH : L-Tyrosine R = H : L