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Mechanistic investigations into the palladium-catalyzed decarboxylative allylic alkylation of ketone enolates using the PHOX ligand architecture

Citation

Sherden, Nathaniel H. (2011) Mechanistic investigations into the palladium-catalyzed decarboxylative allylic alkylation of ketone enolates using the PHOX ligand architecture. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechTHESIS:05312011-072858726

Abstract

Palladium-catalyzed asymmetric allylic alkylation has become a large and important field for chemical synthesis. Many methodologies in this field offer mild conditions under which challenging and important molecular features can be reliably synthesized, including chiral all-carbon quaternary stereocenters. As a result, palladium- catalyzed asymmetric allylic alkylation has found significant use in total synthesis, and growing use in industry. While the general process of palladium-catalyzed asymmetric allylic alkylation has been studied for decades, there have been a number of recent modifications and developments, such as asymmetric versions of decarboxylative allylic alkylation procedures that are not yet well understood. The development of future implementations and improvements to palladium-catalyzed asymmetric allylic alkylation and related methodologies is expected to be facilitated by a better understanding of these more recent developments, and thus further mechanistic investigation is warranted. Reported herein is a set of investigations into the palladium-catalyzed decarboxylative asymmetric allylic alkylation of ketone enolates using the PHOX ligand architecture. By monitoring the reaction via 31P NMR, a series of previously unidentified key intermediates is discovered. Two representatives of these key intermediates are isolated and characterized. The solution behavior of these species under reaction-like conditions is studied along with a few novel and related complexes. The role of these intermediates and their impact on the behavior of the reaction and product formation is discussed. Previously confounding experimentally observed behavior for this methodology is rationalized via the properties elucidated for these discovered intermediates.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Palladium; Asymmetric Allylic Alkylation; Mechanism; Catalysis; Palladium Carboxylate; Palladium Carbonate; Eta-1 allyl;
Degree Grantor:California Institute of Technology
Division:Chemistry and Chemical Engineering
Major Option:Chemistry
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Stoltz, Brian M.
Thesis Committee:
  • Bercaw, John E. (chair)
  • Reisman, Sarah E.
  • Peters, Jonas C.
  • Stoltz, Brian M.
Defense Date:2 March 2011
Record Number:CaltechTHESIS:05312011-072858726
Persistent URL:http://resolver.caltech.edu/CaltechTHESIS:05312011-072858726
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:6476
Collection:CaltechTHESIS
Deposited By: Nathaniel Sherden
Deposited On:31 May 2011 23:07
Last Modified:26 Dec 2012 04:36

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PDF (Full Thesis) - Final Version
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PDF (Chapter 1-The History and Previous Investigations of Palladium-Catalyzed Decarboxylative Asymmetric Allylic Alkylation of Ketone Enolates Using the PHOX Ligand Architecture) - Final Version
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PDF (Chapter 2-Unusual Allylpalladium Carboxylate Complexes: Identification of the Resting State of Catalytic Enantioselective Decarboxylative Allylic Alkylation Reactions of Ketones) - Final Version
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PDF (Appendix 1-Spectra of Compounds Relevant to Chapter 2) - Final Version
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PDF (Appendix 2-X-Ray Crystallographic Data Relevant to Chapter 2) - Final Version
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PDF (Chapter 3-Solution Structure and Behavior of Palladium Allyl Carboxylates and Carbonates) - Final Version
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PDF (Appendix 3-Comprehensive Bibliography) - Final Version
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