• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 55
  • 17
  • 6
  • 4
  • 3
  • 2
  • 2
  • 1
  • 1
  • Tagged with
  • 116
  • 44
  • 35
  • 33
  • 26
  • 25
  • 22
  • 20
  • 19
  • 19
  • 17
  • 16
  • 16
  • 15
  • 14
  • 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

Studies towards the total synthesis of the epothilones A and B

Fletcher, Jane Elaine January 2000 (has links)
No description available.
2

Palladium-Catalyzed Inter- and Intramolecular Allylic Oxidation Reactions of Olefins

Check, Christopher 17 December 2012 (has links)
No description available.
3

The diastereodivergent synthesis of polysubstituted alkenes through lithiation-borylation methodology

Hesse, Matthew James January 2014 (has links)
No description available.
4

Synthesis and reactions of epoxides

Khan, Afzal January 1998 (has links)
No description available.
5

Beyond asymmetric allylic amination: exploring the chemistry of rhodium-catalyzed reactions of allylic trichloroacetimidates in the synthesis of nitrogen and 1,2-diamine heterocyclic compounds

Mwenda, Edward 01 May 2018 (has links)
Chiral amines are ubiquitous functionalities found in the architecture of the natural world and have been embedded into materials, catalysts, pharmaceuticals, agrochemicals, and bioactive natural products. However, limited approaches are accessible for the construction of an enantioenriched tertiary or quaternary-containing amine. This thesis describes the development of new methodologies for the synthesis of 7-membered nitrogen-containing heterocycle and 1,2-diamine compounds. Chapter one describes the application of dynamic kinetic asymmetric amination (DYKAT) of branched allylic acetimidates in the synthesis of 2-alkyldihydrobenzoazepin-5-ones. These 7-membered-ring aza-ketones are generated in good yield with high enantiomeric excess through sequential rhodium-catalyzed allylic amination with 2-amino aryl aldehydes followed by intramolecular olefin hydroacylation of the resulting alkenals. This two-step procedure is efficient, straightforward and convenient for the enantioselective preparation of these ring systems. In Chapter two, we further extended the methodology towards the allylic amination of racemic secondary and tertiary allylic trichloroacetimidates possessing β-nitrogen substituents, and proximal nitrogen-containing heterocycles, using the DYKAT transformation to provide branched allylic 1,2-diamines with high enantioselectivity. The catalytic system is versatile in the synthesis of 1,2-diamines possessing two contiguous stereocenters, with excellent diastereoselectivity. Additionally, the nitrogen-containing heterocycles suppress competing vinyl azirdine formation, allowing for the high enantioselective syntheses of 1,2-diamines possessing tertiary and quaternary centers. Chapter three gives a very brief outlook on our efforts in rhodium-catalyzed amination strategy in providing access to a variety of enantiopure α-fluoromethylated allylic amines.
6

Stereocontrolled synthesis of polysubstituted tetrahydropyrans and #delta#-lactones via tandem [2,3]-Wittig-anionic oxy-Cope rearrangement

Lee, Wai-Man January 1997 (has links)
No description available.
7

Enantioselective deprotonations of three membered rings

Smith, Torben J. N. January 1997 (has links)
No description available.
8

Synthesis of cyclic ethers : a tandem carbenoid insertion and ylide rearrangement strategy

Krowiak, Steven A. January 1995 (has links)
No description available.
9

Asymmetric allylic and progargylic oxidation reactions

Tolhurst, Keith F. January 1998 (has links)
No description available.
10

Synthesis and Reactivity of Allylic Amines in Palladium Catalysis

Dubovyk, Igor 11 December 2012 (has links)
Reaction of unsymmetrical allylic electrophiles with amines gives rise to regioisomeric allylamines. It was found that linear products result from the thermodynamically controlled isomerization of the corresponding branched products, which form initially. The isomerization was found to be promoted by the presence of acid and active palladium catalyst. The use of base shut down the isomerization pathway and allowed for the preparation and isolation of branched allylamines. This methodology provides a powerful control element, which allows for the installation of quaternary and chiral centres next to nitrogen. Later, the isomerization was combined with ring-closing metathesis to afford the synthesis of exocyclic allylamines from their thermodynamically less-stable endocyclic precursors. This rearrangement became feasible as a result of the electrophilic nature of a C – N bond in allylamines. When compared to the conventional intramolecular allylic amination, such approach escapes chemoselectivity issues, which makes it attractive attractive for late-stage synthetic modifications.

Page generated in 0.0484 seconds