• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • No language data
  • Tagged with
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 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

Transition metal-catalyzed functionalization of carbon-hydrogen bonds in alkenes

Qian, Xiaolin 08 August 2023 (has links) (PDF)
Alkenes can undergo a variety of chemical reactions to form more complex molecules with a range of functional groups. This makes them useful starting materials for synthesizing a wide range of organic compounds. Chapter I provided an overview of the development history of alkenyl C−H bond activation. The early reactions of C−H compounds with metal complexes, as well as stoichiometric activation of the transition metal-activated C–H bond, were discussed. Then the first successful and efficient organometallic-catalyzed transformations of a C−H bond, the first transition metal-catalyzed vinylic C–H functionalization, and the first transition metal-catalyzed olefinic C–H functionalization under mild conditions were demonstrated. Finally, enantioselective vinylic C–H functionalization was discussed. In Chapter II, a method for enantioselective vinylic C(sp2)−H bond activation using a Ru(II) catalyst and a chiral transient directing group was developed. Chiral amine was also utilized to control the Z/E stereoselectivity. The method demonstrated a broad substrate scope with good yield, high Z/E ratio stereoselectivity, and excellent enantioselectivity. Its synthetic utility was demonstrated by the synthesis of key structural motifs of particularly useful natural products and pharmaceutical compounds. Additionally, a rare vinylic C−H bond activated ruthenic complex was isolated and determined by single-crystal X-ray diffraction. The methodology suggested in this work is expected to facilitate the further development of asymmetric vinylic C−H functionalization reactions. In Chapter III, a practical and efficient methodology for Ru(II)-catalyzed enantioselective alkenyl C–H bond functionalization of indole-substituted acrylaldehyde derivatives via the chiral transient directing group (CTDG) strategy to obtain optically active pyrrolo[1,2-a]indole derivatives was suggested. The methodology resulted in a series of optically active products with good yields (up to 80%), good stereoselectivity (up to 25.0:1 Z/E), and excellent enantioselectivity (up to 95% ee). Furthermore, synthetic transformations were explored. Chapter IV presented the first demonstration of a sequentially composed catalytic substitution reaction of alkenes for building multi-amido methylated derivatives while reserving the π- components. The process involved a simple Fe (III)-catalyst and bisamidomethane reagent, which directly and selectively transformed α-substituted styrenes into several biologically and pharmaceutically relevant N-heterocycles through tandem processes.

Page generated in 0.0598 seconds