Regioselective, Nucleophilic Activation of C-F Bonds in o-Fluoroanilines
Hough, Sarita Elizabeth
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Reactions of fluorinated anilines with stoichiometric Ti(NMe2)4 in mesitylene (typically for 23 h at 120 °C) afforded moderate to high yields of the corresponding N,N-dimethyl-o-phenylenediamine derivatives resulting from defluoroamination of a fluorine atom ortho to the NH2 of the starting aniline. Reactivity increased with additional ring fluorination in general accordance with established regiochemical (activating and deactivating) trends. Based on results, we propose a metal-mediated, SNAr-based mechanism. We report the scope and limitations of this reaction and discuss trends in reactivity according to a putative mechanistic scheme.
General Audience Abstract
This thesis describes reactions of fluorinated anilines with titanium amides to make fluorinated 1,2-phenylenediamines. The reaction gives high to moderate yields, and is highly selective for ortho substitution. The scope of the reaction, trends in reactivity among substrates, product characterization, and reaction mechanism are discussed. This reaction is of interest because fluorinated aniline derivatives are a privileged structural motif in pharmaceuticals and agricultural chemicals. The first chapter presents an overview of C-F bond activation and key background information. Chapter 2 is a description of the experiments and an in-depth analysis of their results. Chapter 3 presents detailed characterization data for substances generated in this research. Chapter 4 comprises some concluding remarks and plans for possible future extensions of the research.
- Masters Theses