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  • Investigation of Chain Extension Approaches for the Stereoselective Reagent-Controlled Synthesis of alpha-Heteroatom Substituted Alkyl Boronic Esters

    Creator:
    Barsamian, Adam L.
    Abstract:
    Two distinct strategies were explored for the enantioselective synthesis of α-heteroatom substituted alkyl boronic esters by stereoselective reagent-controlled homologation using transient chiral carbenoid reagents CHYMX (Y = heteroatom, X = nucleofuge, M = electrofuge). In the first case, a stereospecific reagent-controlled homologation (sStReCH) approach to α-alkoxyalkylboronates using α-metalated S,O- and...
    Resource Type:
    Dissertation
    Full Text:
    Investigation of Chain Extension Approaches for the

  • 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...
    Resource Type:
    Dissertation
    Full Text:
    chain. Allylsilylation of 149 with 195 afforded 202, which was linked by Wittig olefination with 215

  • Water and methanol adsorption on a series of organic complexes of montmorillonite

    Creator:
    Carter, Loren Sheldon
    Abstract:
    Water and methanol adsorption isotherms at 25° and 37° C. were determined on a series of organo-bentonite clays. The clays differed in the length of the carbon chain attached to the amine adsorbed in the cation exchange position. The amines used had carbon chains of 4, 6, 8, 10, 12,...
    Resource Type:
    Masters Thesis
    Full Text:
    about one millimeter extension per milligram of load. The isotherms were typical type II isotherms and

  • Development of Methods for Stereoselective Carbon-Carbon Bond Formation

    Creator:
    Wu, Zhenhua
    Abstract:
    Three distinct methods to achieve the stereoselective synthesis of carbon-carbon bonds were investigated, encompassing: (i) the formation of axially chiral biaryl molecules by enantioselective Suzuki cross-coupling, (ii) the synthesis of α-phenylalkylboronic esters by enantioselective chain extension, and (iii) the stereospecific synthesis of alkenes by eliminative cross-coupling of enantioenriched sp³-hybridized carbenoids....
    Resource Type:
    Dissertation
    Full Text:
    enantioselective chain extension, and (iii) the stereospecific synthesis of alkenes by eliminative cross-coupling

  • Studying fusion reactions for effect of PCN on heavy nucleus formation and for nuclear structure effects

    Creator:
    Naik, Radhika
    Abstract:
    The fusion reaction ²⁰⁸Pb (⁵⁰Ti, xn) ²⁵⁸⁻x Rf (x = 1-3) was studied to determine PCN (probability that the mononucleus system evolves to form a compound nucleus inside the fission saddle point) and to establish the value of Wsur (survival probability) for the given reaction experimentally. The fission excitation function...
    Resource Type:
    Dissertation
    Full Text:
    larger than 2.5fm given by 1/30 AR × . This extension of the radius is attributed to the presence of

  • The normal vibrational analysis of polyacetaldehyde

    Creator:
    Lee, Dorothy
    Abstract:
    A method of calculating the normal vibrations of polymer molecules is presented in detail. The method is based on that used by Schachtschneider and Snyder in their analysis of polypropylene but has not heretofore been published. The factoring of the infinite matrix and reduction to the coordinates of the unit...
    Resource Type:
    Dissertation
    Full Text:
    rnolecules to rnake the extension to polyrner rnolecules by this rnethod. The geometry of polyrner chains

  • Synthesis, characterization, and analysis of nitroaromatic compounds

    Creator:
    McIntosh, Melissa Luana
    Abstract:
    Nitroaromatic compounds have important chemical applications and can be found in nature as pollution sources. Synthetic nitroaromatic compounds have been used in a variety of materials including explosives, pharmaceuticals, dyes, plastics, and pesticides. These compounds can find their way into the environment through normal or improper disposal methods. Poly-aromatic compounds...
    Resource Type:
    Masters Thesis
    Full Text:
    extension of this methodology to the synthesis of heterocycles such as poly-aromatic triazoles and

  • Stereospecific Synthesis of Stereotriad Motifs and Alkenes Using Enantioenriched sp³-Hybridized Carbenoids

    Creator:
    Xun, Sun
    Abstract:
    Enantioenriched sp³-hybridized carbenoid reagents CR1R2MX (X = nucleofuge, M = electrofuge) of different types were investigated for the synthesis of polysubstituted alkyl chains by iterative stereospecific reagent-controlled homologation (StReCH) and for the stereospecific connective synthesis of alkenes by eliminative cross-coupling. In the first part, putative enantioenriched α-chloroalkyllithiums (CHRLiCl) were employed...
    Resource Type:
    Dissertation
    Full Text:
    contiguous stereotriad motif were separately targeted by triple chain extension of B-phenethyl boronic

  • Dynamics and Design of Green Fluorescent Protein-Inspired Superphotoacids and Red-Emitting Fluorophores with Transient Absorption and Femtosecond Stimulated Raman Spectroscopy

    Creator:
    Chen, Cheng
    Abstract:
    In the past decades, femtosecond stimulated Raman spectroscopy (FSRS) has been gaining tremendous popularity in fundamental sciences stemming from chemistry to biology. It is capable of capturing both equilibrium and non-equilibrium structural information across a broad range of timescales with simultaneously high temporal and spectral resolutions. Femtosecond transient absorption spectroscopy...
    Resource Type:
    Dissertation
    Full Text:
    require large π-conjugation extension and hence provides space for further chemical engineering for

  • 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:
    enantiomeric excess. Extension of this reaction to vinylic halides using the same catalyst is probed but