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Filtering by: Alternative title ssim ORESU-R-19-013 Remove constraint Alternative title ssim: ORESU-R-19-013 Advisor White, James D. Remove constraint Advisor: White, James D. Resource Type Dissertation Remove constraint Resource Type: Dissertation

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  • An approach toward the synthesis of euonyminol and cathedulin K- 19

    Creator:
    Shin, Hyunik
    Abstract:
    A synthetic approach toward the two major fragments of cathedulin K-19, euonyminol (4) and dimethyl cathate (69), was investigated. Synthesis of dimethyl cathate was accomplished in 3 steps starting from 73. Efforts directed towards the synthesis of euonyminol, a highly oxygenated dihydroagarofuran sesquiterpene, was advanced to a stage in which...
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    Dissertation
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    hence at C-9' of K-19, possess the (S) configuration.22 ROTBS O R = CHO R = C=CH (i) R = TBS R = H

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

    Creator:
    Smits, Helmars
    Abstract:
    Studies towards the total synthesis of (−)-kendomycin (1), a bacterial metabolite with a unique molecular architecture and pronounced biological activity, are described. These studies resulted in the synthesis of advanced intermediate 208, containing all of the carbon atoms of 1. A Dötz annulation between alkyne 122 and novel chromium carbenoid...
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    bacterial type-I polyketide synthase with the synthesis proceeding in the direction from C-5 to C-19

  • Synthesis of metabolites from the ascomycetes : I. The synthesis and absolute configuration of leptosphaerin : II. Approaches to the synthesis of byssochlamic acid

    Creator:
    Pallenberg, Alexander J.
    Abstract:
    Part I. The total synthesis of (+)-leptosphaerin (2), a metabolite of the marine Ascomycete Leptosphaeria Oraemaris (Linder) was achieved, unambiguously establishing both the relative and absolute stereochemistry of this natural product. This synthesis also resolved the long-standing question of which of the isomeric structures 1 or 2 correctly represents the...
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    Dissertation
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    mannitol and ethyl pyruvate. In the key step a protected form of R-(+)-glyceraldehyde (3) underwent a

  • 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...
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    produced by this method in high enantiomeric excess. This protocol was used to synthesize (R)-Montelukast

  • Tandem intramolecular photocycloaddition-retro-Mannich fragmentation as a route to indole and oxindole

    Creator:
    Li, Yang
    Abstract:
    Irradiation of a tryptamine linked through its side-chain nitrogen to an alkylidene malonate residue results in an intramolecular [2 + 2] cycloaddition to the indole 2,3-double bond. The resultant cyclobutane undergoes spontaneous retro-Mannich fission to produce a spiro[indoline-3,3-pyrrolenine] with relative configuration defined by the orientation of substituents in the transient...
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    ] photocycloaddition to the total synthesis of natural products. Inter- as well as O O O O O R O R O R R R

  • Total synthesis of phorboxazole A

    Creator:
    Lee, Tae Hee
    Abstract:
    The total synthesis of a highly potent cytotoxic marine natural product, phorboxazole A, is described. Both a palladium(II)-mediated and a palladium(II)-catalyzed intramolecular alkoxycarbonylation were used as key steps for the preparation of the two cis-2,6-disubstituted tetrahydropyran rings (C22-C26 and C11-C15) of phorboxazole A. The synthesis used a convergent approach involving...
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    of (R)- and (S)- MTPA esters of 166…….. 1H NMR Spectra of Synthetic (a) and Natural (b

  • 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...
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    , Professor Rich G. Carter, Professor Paul R. Blakemore, Professor Kevin P. Gable, Professor Janet Tate and

  • 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...
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    steps from (R)-methionine. Intramolecular nitrone cycloaddition of 176 afforded the unstable

  • Studies on the synthesis of the "northern" and "southern" segments of boromycin and aplasmomycin

    Creator:
    Kang, Myung Chol
    Abstract:
    The stereocontrolled synthesis of the southern lactone 17 of boromycin and of the northern segments of both boromycin and aplasmomycin are described. The syntheses begin with enantioselective epoxidation of 3-buten-2-ol (42) to provide the optically active 2(S),3(R) epoxy alcohol 43. The absolute configuration was confirmed by preparing 43 from (-)-2,3-dihydroxybutyric...
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    begin with enantioselective epoxidation of 3-buten-2-ol (42) to provide the optically active 2(S),3(R

  • Approaches to the synthesis of methymycin

    Creator:
    Raghavan, Palaykotai Rajagopalan
    Abstract:
    Several approaches to the synthesis of methymycin were investigated. Segment A (39), containing functionality corresponding to C-9, 10, and 11 of methynolide was made in six steps from propionaldehyde in an overall yield of 37%. Oxidation of 34 with silver nitrate gave 35 which, upon hydroxylation with hydrogen peroxide, gave...
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    . The (+) acid was found to have R,R configuration. This substance was converted to its acetonide