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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.
21

Synthesis and characterization of the first homoaromatic organometallic carbene complexes

Radcliffe, Marc Dudley, January 1982 (has links)
Thesis (Ph. D.)--University of Florida, 1982. / Description based on print version record. Typescript. Vita. Includes bibliographical references (leaves 80-82).
22

Synthetic studies towards conocurvone : a novel synthesis of trimeric quinone via the first reactions of carbene complex with conjugated triynes /

Jiang, Xiao-Wu. January 2002 (has links)
Thesis (Ph. D.)--University of Chicago, Department of Chemistry, December 2002. / Includes bibliographical references. Also available on the Internet.
23

The replaceability of certain methylene groups and the relation of constitution to the stability of the C=C linkage,

Moyer, Harvey Vernon. January 1927 (has links)
Thesis (Ph. D.)--University of Kansas. / Description based on print version record.
24

Bis-(alkylthio)-carbenes

Banitt, Elden Harris, January 1964 (has links)
Thesis (Ph. D.)--University of Wisconsin, 1964. / Typescript. eContent provider-neutral record in process. Description based on print version record. Bibliography: leaves 106-109.
25

The reaction of carbenes with ketene acetals cyclopropanone acetals

Weyna, Philip Leo, January 1959 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1958. / Typescript. Abstracted in Dissertation abstracts, v. 19 (1959) no. 8, p. 1924. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaf 85).
26

Carbenes and radicals from benzyloxy [delta]3-1,3,4-oxadiazolines /

Merkley, Nadine. January 2001 (has links)
Thesis (Ph.D.) -- McMaster University, 2001. / [Delta] in title is a Greek letter. The number 3 in title is superscript. Includes bibliographical references (leaves 147-162). Also available via World Wide Web.
27

Generation and reactions of aryloxy and diaryloxycarbenes /

Lu, Xiaosong. January 2001 (has links)
Thesis (Ph.D.) -- McMaster University, 2001. / Includes bibliographical references (leaves 168-175). Also available via World Wide Web.
28

Copper-catalyzed Enantioselective Allylic Substitutions and Conjugate Additions Promoted by Chiral Sulfonate- or Alkoxy-containing N-heterocyclic Carbenes

Shi, Ying January 2017 (has links)
Thesis advisor: Amir H. Hoveyda / Chapter 1. A Review of Sulfonate-Containing NHC Ligands in Copper-Catalyzed Enantioselective Transformations—Maneuvering Selectivities in Tight Space. A comprehensive review of enantioselective copper-catalyzed transformations, which are promoted by a chiral N-heterocyclic carbene metal complex that features a unique sulfonate motif, is provided in this chapter. Reactions have been categorized into four sets: allylic substitutions conjugate additions, Cu-B additions alkenes and multicomponent reactions. The mechanistic scenarios provided by DFT calculations accounts for their uniquely reaction profile in enantioselective allylic substitutions (EAS), enantioselective conjugate additions (EAS) and enantioselective Cu-B additions to alkenes. Mechanistic investigations (density functional theory calculations and deuterium labeling) point to a bridging function for an alkali metal cation connecting the sulfonate anion and a substrate’ s phosphate group to form the branched addition products as the dominant isomers via Cu(III) π -allyl intermediate complexes in EAS reactions. Sulfonate-bearing NHC ligand with different substitution patterns promote EAS reactions with different reactivity and enantioselectivity. We also developed a guideline to follow to choose the proper sulfonate-based NHC ligands according to the combination of the substrates and the nucleophiles. Chapter 2. NHC–Cu-Catalyzed Enantioselective Allylic Substitutions with Silyl-protected Propargyl Boron Reagent to Generate Tertiary and Quaternary Carbon Stereogenic Centers. Catalytic allylic substitution reactions involving a propargylic nucleophilic component are presented; reactions are facilitated by 5.0 mol % of a catalyst derived from a chiral N-heterocyclic carbene (NHC) and a copper chloride salt. A silyl-containing propargylic organoboron compound, easily prepared in multi-gram quantities, serves as the reagent. Aryl- and heteroaryl-substituted disubstituted alkenes within allylic phosphates and those with an alkyl or a silyl group can be used. Functional groups typically sensitive to hard nucleophilic reagents are tolerated, particularly in the additions to disubstituted alkenes. Reactions may be performed on the corresponding trisubstituted alkenes, affording quaternary carbon stereogenic centers. Incorporation of the propargylic group is generally favored (vs allenyl addition; 89:11 to >98:2 selectivity); 1,5-enynes can be isolated in 75−90% yield, 87:13 to >98:2 SN2′:SN2 (branched/linear) selectivity and 83:17−99:1 enantiomeric ratio. Utility is showcased by conversion of the alkynyl group to other useful functional units. Application to stereoselective synthesis of the acyclic portion of antifungal agent plakinic acid A, containing two remotely positioned stereogenic centers, by sequential use of two different NHC–Cu-catalyzed enantioselective allylic substitution (EAS) reactions further highlights utility. Chapter 3. NHC–Cu-Catalyzed Enantioselective Allylic Substitutions with Methylenediboron to Generate Tertiary and Quaternary Carbon Stereogenic Centers. A catalytic EAS method for the site- and enantioselective addition of commercially available di-B(pin)-methane to disubstituted allylic phosphates is introduced. Transformations are facilitated by a sulfonate-containing NHC–Cu complex and products are obtained in 63–95% yield, 88:12 to >98:2 SN2’/SN2 selectivity, and 85:15–99:1 enantiomeric ratio. The utility of the approach is highlighted by its application to the formal synthesis of the cytotoxic natural product rhopaloic acid A, in an all-catalytic-method synthesis route. Catalytic EAS methods of the di-B(pin) methane to Z-trisubstituted allylic phosphates are also disclosed and DFT calculations provide insights to the stereochemical models for those transformations and rationales for the choice of Z-trisubstituted allylic phosphates as the starting materials. Chapter 4. Enantioselective NHC–Cu-Catalyzed Prenyl Conjugate Additions to Enoates to Generate Tertiary Carbon Stereogenic Centers. An efficient catalytic protocol for generation of prenyl-bearing tertiary carbon stereogenic centers from aryl-substituted enoates was achieved in the presence of a chiral alkoxy-based NHC–Cu complex. A range of aryl and heteroaryl-substituted substrate were suitable substrates, the corresponding prenyl conjugate addition products were generated in up to 94% yield and 95:5 enantioselectivity. The utility of the current method has been shown in the application to the synthesis of a selective integrin antagonist. DFT calculations provided a stereochemical model for the ECA reaction employing alkoxy-containing NHC–Cu catalyst. / Thesis (PhD) — Boston College, 2017. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.
29

An evaluation of methylenedioxyindene analogues in cardiac muscle systems /

Lynch, Joseph John January 1982 (has links)
No description available.
30

I. Preparation and characterization of m?-xylylene II. Solid state reactions and kinetics of arylcarbenes /

Wright, Bradford Barry January 1983 (has links)
No description available.

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