• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 35
  • 32
  • 6
  • 3
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 115
  • 31
  • 30
  • 30
  • 24
  • 19
  • 19
  • 19
  • 15
  • 15
  • 15
  • 13
  • 12
  • 12
  • 11
  • 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.
1

Aminomercuration of carbonyl-containing olefins

Spanggord, Ronald Jay, 1942- January 1971 (has links)
No description available.
2

Planar chiral ferrocene lithium amide bases : a new generation of bases for asymmetric synthesis

Arnall-Culliford, Jennifer Charlotte January 2002 (has links)
No description available.
3

Development of 1,2,3-triazole-borane complex as effective reagent for aldehyde/ketone reductive amination

Liao, Wenyan. January 2009 (has links)
Thesis (M.S.)--West Virginia University, 2009. / Title from document title page. Document formatted into pages; contains xi, 169 p. : ill. Includes abstract. Includes bibliographical references (p. 59-65).
4

New systems for asymmetric electrophilic heteroatom transfer

Murrell, Victor Leon January 1999 (has links)
No description available.
5

Réalisation de couplages pallado-catalysés en série thiophénique : synthèse de composés biologiquement actifs / Palladium-catalyzed cross-coupling reactions in the thiophene serie : synthesis of biogically active compounds

Begouin, Agathe 04 September 2007 (has links)
La N-arylation d'amines primaires et secondaires par couplages C-N palladocatalysés de Buchwald- Hartwig est une méthode efficace de synthèse d'arylamines. Jusqu'à présent, la synthèse d'arylamines en série thiophénique n'avait été que peu décrite. Nous nous sommes ainsi intéressés à la réactivité de dérivés substitués des 2- et 3-bromothiophènes dans les couplages C-N palladocatalysés. Par la suite, nous avons également étudié la réactivité d'aminothiophènes dans ces mêmes réactions de couplage. Un grand nombre d'arylamines a ainsi pu être synthétisé. La synthèse de thiénopyrimidinones a aussi été effectuée via la réalisation en "one-pot" d'une réaction de couplage C-N suivie d'une cyclisation intramoléculaire / N-Arylation of primary and secondary amines by Buchwald-Hartwig C-N cross-coupling reactions is a very convenient pathway for the synthesis of arylamines. Up to now, only few examples of arylamines synthesis were described in the thiophene series, although arylaminothiophenes generally show very interesting biological and electronic properties. Thus, we investigated the reactivity of 2- and 3- bromothiophene derivatives in palladium-catalyzed cross-coupling. Then we also studied the reactivity of aminothiophenes in those same cross-coupling reactions. Using this way, the expected diarylamines were successfully synthesized. An easy access to thienopyrimidinone derivatives was also described via a one-pot C-N coupling and intramolecular cyclization
6

Towards the novel enantioselective synthesis of the nucleoside antibiotic, polyoxin J

Gethin, David Morris January 1997 (has links)
No description available.
7

Copper-Catalyzed Amination of Indoles via C-H Bond Activation

Pan, Ming-kai 07 September 2012 (has links)
A new protocol for direct amination of N-Methyl-2-phenylindole catalyzed by copper(II) trifluoromethanesulfonate was presented. Both of (E)-N-(1,1'-Dimethyl-2,2' -diphenyl-2,3'-biindolin-3-ylidene)-4-methylbenzenesulfonamide¡]4¡^and 4-methyl -N-(1-methyl-2-phenyl-1H-indol-3-yl)benzenesulfonamide¡]2¡^were obtained under the optimal reaction conditions (2.5 mol% Cu(OTf)2, 1.2 equiv PhI=O, 0.7 equiv PhI=NTs heated at 25 ¢J in acetonitrile for 1 hour) in 78 % and 11 % yields, respectively. In addition, (E)-N-(2-hydroxy-1-methyl-2-phenylindolin-3-ylidene)-4-methylbenzene sulfonamide ¡]6¡^and (E)-N-(1,1'-dimethyl-2,2'-diphenyl-2,3'-biindolin-3-ylidene) -4-methylbenzenesulfonamide ¡]4¡^were synthesized in 47 % and 24 % yields, respectively, by using 5 mol% Cu(OTf)2, 2 equiv PhI=O, 1.2 equiv PhI=NTs at ambient temperature in acetonitrile for 1 hour. Finally, 4-methyl-N-(1-methyl-2-oxo-3-phenyl indolin-3-yl)benzenesulfonamide ¡]3¡^and 1,1'-dimethyl-2,2'-diphenyl-2,3'-biindolin -3-one ¡]7¡^can be formed under the following reaction condition, 5 mol% Cu(OTf)2, 2 equiv PhI=O, 1.2 equiv PhI=NTs and 3 equiv Ag2CO3 heated at 100 ¢J in acetonitrile for 1 hour, in 41% and 22% yields, respectively.
8

Azidomethyl phenyl sulfide a synthon for NH2⁺ /

Pearson, William Hardy. January 1982 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1982. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 426-461).
9

Study of Bis-Imidazol-2-Ylidines as Ligands for Transition Metal Catalyzed Coupling Reactions

Turnbull, Stanhope 17 December 2004 (has links)
Two bis-imidazol-2-ylidine N-heterocyclic carbenes have been employed as ancillary ligands in an attempt to illustrate their utility in the palladium-mediated preparation of aryl ethers from aryl halides. Ullman-type homo-coupling of the aryl halides persistently occurred instead of ether formation. One of the well known N-heterocyclic carbenes, IPr, was employed with the same results. A variety of reaction conditions and reagents were investigated including solvents, N-heterocyclic carbene species, palladium source, alkoxide base, palladium to ligand ratio and reaction time. Reactivity of the individual N-heterocyclic carbenes as ancillary ligands in the palladium-catalyzed amination reaction of aryl halides was investigated to determine functionality of the carbenes. Alternative procedures to prepare the key intermediates in the synthesis of the bisimidazol- 2-ylidines were developed. In this study the aryl imidazoles were prepared from the corresponding phenol and carbonyldiimidazole. Subsequent N-alkylation then furnished the Nheterocyclic carbenes in high yield. Novel unsymmetrical N-heterocyclic carbenes with aryl and benzylic side groups have been synthesized as models for the subsequent synthesis of unsymmetrical polymer-bound Nheterocyclic carbenes. The unsymmetrical ligands were employed in the palladium-catalyzed amination of aryl halides and in the Suzuki-Miyaura Reaction. Two Merrifield resin polymerbound N-heterocyclic carbene ligands were then synthesized and employed in the aryl amination and Suzuki-Miyaura Reactions. Both reactions were greatly accelerated by the implementation of microwave heating. The Merrifield resin polymer-bound palladium-ligand complexes have been recycled through several reactions without loss of activity.
10

Cu-Catalyzed Amination of sp3 C-H Bonds

Wang, Anqi 14 December 2018 (has links)
Presented herein is the development, optimization and mechanistic investigation of an Cu catalytic system for the oxidation of sp 3 C-H bond of simple arenes to form C-N bond in a direct manner. Due to the prevalence of nitrogen containing molecules among biologically active synthetic and natural compounds, synthetic chemists have always been motivated to develop new efficient ways to directly transform ubiquitous carbonhydrogen (C-H) bonds into carbon- nitrogen (C-N) bonds. Recent advances in transition metal catalyzed C-H amination has demonstrated that it is not only possible but also practical to functionalize C-H bonds that are often considered inert in one step, circumventing more classical, sequential functional group interconversion approaches. Existing catalytic systems that promote the transition metal-catalyzed, amination of sp 3 C-H bonds displayed certain limitations, especially the lack of built-in versatility and stability in their amination reagents. To overcome these drawbacks of these existing catalytic system, our group developed a new Cu amination protocol that deployed versatile hydroxylamine-based with general structure RSO 2 NH-OAc as amination reagents. Although the reactivity of the catalytic system ranges from moderate to good, the catalytic system provided promising results using simple arene substrates. Further detailed mechanistic studies revealed that the reaction undergoes an unprecedented two subsequent cycles divided by a major intermediate PhCH 2 (NTsOAc). The proposed mechanism is consistent with radical clock experiments, observed reaction profiles, the need for excess of substrate, and the documented role of the ligand in the catalytic system. The exciting proposed mechanism led to a new type of copper catalyzed amination reaction using N- fluorobenzenesulfonimide (NFSI) as oxidant, which overcomes the need to use an excess of substrate. A wide range of unactivated amines HNR 1 R 2 , including sulfonamide and benzamide, can be used as amine sources, which enables the installation of different nitrogen groups on benzylic sp 3 C-H bond of a variety of substrates in moderate to excellent yield. Moreover, mechanistic experiments and critical analysis of related reactivity in the literature provide insight into the catalytic cycle, resulting in a proposal that details the role of both oxidant and amine source in the new system.

Page generated in 0.1026 seconds