Computational Insight into Homogeneous Organopalladium Catalysis

Author: Keith, John Andrew

Year: 2008

Degree: Dissertation (Ph.D.)

Advisor: Goddard, William A., III

Committee Members: Stoltz, Brian M.; Gray, Harry B.; Bercaw, John E.; Goddard, William A., III

Option: Chemistry

DOI: 10.7907/FAS9-DV26

Abstract

An investigation of modern computational simulation techniques and their results in describing two notable organopalladium reactions are discussed. First, a methodology for computational quantum chemistry simulations of homogeneous catalysis is presented. We find that through careful consideration of electronic and thermodynamic energy contributions, practical methods are available to accurately study complicated reaction mechanisms and to make educated predictions about their chemistry. We apply this technique to develop the first full analysis of the Wacker Process, olefin oxidation by PdCl2 catalysts, effectively uniting nearly 50 years of research into one mechanistic model. Key findings include the identification of competitive rate determining steps that are dependent on ion concentrations and the inaccessibility of [beta]-hydride elimination during product formation. The second analysis addresses the unique performance of the enantioselective Tsuji-allylation reaction, a reaction the great potential in the fields of asymmetric catalysis and natural product synthesis. In this reaction, calculations point towards enantioselectivity determined after the rate determining step. Intriguingly, we find that C-C coupling is facile in a variant to canonical reductive elimination containing characteristics of both reductive cheletropic and Claisen rearrangements. Lastly, a model is presented to direct improved catalyst design. In total, this dissertation presents an outline for practical quantum chemical simulation of complicated and elaborate organopalladium reactions.

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