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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.
341

Modelling studies of magnesium-dependent phosphate ester processing enzymes

Yun, Joanne W., 1970- January 1996 (has links)
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1996. / Includes bibliographical references. / by Joanne W. Yun. / Ph.D.
342

Solid state NMR studies of structure and dynamics in systems of biological interest

Long, Joanna R. (Joanna Ruth) January 1997 (has links)
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1997. / Includes bibliographical references. / by Joanna R. Long. / Ph.D.
343

Nickel-catalyzed preparation of acrylamides from alpha olefins and isocyanates ; Synthetic studies toward ripostatin A / Synthetic studies toward ripostatin A

Schleicher, Kristin D. (Kristin Diann) January 2010 (has links)
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2010. / Vita. Cataloged from PDF version of thesis. / Includes bibliographical references. / Chapter I. In the presence of the N-heterocyclic carbene ligand IPr, the nickel(0)-catalyzed coupling reaction of a-olefins and branched aliphatic isocyanates provides c,-unsaturated amides arising from preferential C-C bond formation at the 2-position of the olefin. This sense of regioselectivity contrasts with the observed carboxamidation at the 1-position of the olefin when phosphine ligands are used. In this reaction, a simple alkene acts as the functional equivalent of a 2-alkenylmetal reagent. ... Chapter II. Synthetic studies on the antibiotic natural product ripostatin A have been carried out with the aim of constructing the C9-C1O bond via a nickel(0)-catalyzed coupling reaction of enynes and epoxides developed in our laboratory, followed by rearrangement of the resulting dienylcyclopropane intermediate to afford the skipped 1,4,7-triene. ... A cyclopropyl enyne fragment corresponding to C1-C9 of ripostatin A can be synthesized in high yield over 10 steps and was demonstrated to be a competent substrate for the nickel(0)-catalyzed coupling reaction with a model epoxide. The origin of regioselectivity in this particular transformation is also discussed. ... Several synthetic approaches towards the desired C1O-C26 epoxide fragment have been pursued. The presence of the C19-C20 trisubstituted olefin renders introduction of the epoxide via oxidation of or iodocyclization onto a terminal alkene unsuitable. Access of the epoxide by way of nucleophlic displacement should circumvent these problems. The C13 stereocenter can be set via the allylation and reductive decyanation of a cyanohydrin acetonide. ... A mild, fluoride-promoted decarboxylation enables the construction of the C15-C16 bond via an aldol reaction. This product of this transformation is of the correct oxidation state and three steps removed from the targeted epoxide fragment. / by Kristin D. Schleicher. / Ph.D.
344

Reaction dynamics studied by photoemission spectroscopy

Imre, Dan January 1984 (has links)
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1984. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. / Includes bibliographical references. / by Dan Imre. / Ph.D.
345

The development of iterative and cascade methods for the rapid synthesis of ladder polyether natural products

Heffron, Timothy Paul January 2005 (has links)
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2005. / MIT Science Library copy: Issued in leaves, in a 2 v. set. / Also issued in leaves, in a 2 v. set. Vita. / Includes bibliographical references . / I. The Development of Methods for the Iterative Synthesis of Polytetrahydropyrans An iterative method comprising chain homologation, epoxidation, 6-endo cyclization, and protiodesilylation was developed. Notable achievements include the development of a novel propargyl organocopper coupling method, and the complete control of stereoselectivity and regioselectivity during the iterative synthesis of a tristetrahydropyran. The synthesis of the tristetrahydropyran was achieved in 18 total operations. ... (1) homologation (2) epoxidation (3) cyclization (4) protiodesilylation ... II. The Development of a Cascade Synthesis of Polytetrahydropyrans with No Directing Groups at Ring Junctions Cascade approaches to trans-fused tetrahydropyrans were studied. After exploring acid-promoted cascade cyclizations of polyepoxysilanes and polyepoxides without directing groups, the base-promoted cascade cyclization of polyepoxysilanes was realized. In this method, as many as five operations take place in a single step to provide a tristetrahydropyran with no directing groups at any ring junctions. The synthesis of the tristetrahydropyran was accomplished in 11 steps. ... / by Timothy Paul Heffron. / Ph.D.
346

The analysis and interpretation of high resolution nuclear magnetic resonance spectra

Fessenden, Richard W January 1958 (has links)
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1958. / Vita. / Includes bibliographical references (leaves 103-104). / by Richard Warren Fessenden. / Ph.D.
347

A study of the reaction of hydrogen iodide with silicon

Klein, Carolyn Horvey January 1934 (has links)
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1934. / Includes bibliographical references (leaf 29). / by Carolyn H. Klein. / M.S.
348

Measurement and assignment of the size-dependent optical spectrum in cadmium selenide (CdSe) quantum dots

Norris, David J. (David James) January 1995 (has links)
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1995. / Includes bibliographical references. / by David J. Norris. / Ph.D.
349

Studies directed toward the total synthesis of salvilenone

Choi, HuiWon January 2005 (has links)
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2005. / Vita. / Includes bibliographical references. / Model studies on the total synthesis of salvilenone, a phenalenone diterpene found in the roots of Salvia miltiorrhiza Bunge, are reported via a double annulation strategy. The key steps in the proposed synthesis involve a regiocontrolled benzannulation involving the photochemical Wolff rearrangement of an a-diazo ketone and an alkoxy acetylene moiety which assembles an aromatic ring in one step from acyclic precursors followed by an intramolecular [4 + 2] cycloaddition of a conjugated enyne and benzyne intermediate. / by HuiWon Choi. / S.M.
350

The synthesis and applications of a biaryl-based asymmetric phosphine ligand

Hirai, Satoko January 2005 (has links)
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2005. / Includes bibliographical references. / The asymmetric biaryl backbone of a dialkylbiphenyl phosphine ligand was developed, synthesized, and resolved. The application of the chiral phosphine ligand to the asymmetric Suzuki-Miyaura cross-coupling reaction was also investigated. This phosphine ligand has yielded promising results in the asymmetric Suzuki-coupling of hindered boronic acids with the electron-rich aryl bromide, 1-bromo-2- methoxynaphthalene, to synthesize biaryls in modest enantioselectivity. / by Satoko Hirai. / S.M.

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