Towards new zwitterioinic difluoroglycine analogues: preparation methods and reactivity studies
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Date
2025
Authors
Lilienthal, Elaura O.
University of Lethbridge. Faculty of Arts and Science
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Lethbridge, Alta. : University of Lethbridge, Dept. of Chemistry and Biochemistry
Abstract
Research into new methods of fluorination is imperative as the addition of fluorine onto organic molecules has a great influence on a compound’s properties. Difluorocarbene can be used in such fluorination methods, and it is currently being explored for its unique properties. The purpose of this thesis was to see if it was possible to create new zwitterionic difluoroglycine-derived difluorocarbene precursors, and to test their ability against the previously reported phosphine-based analogue. The formation of the phosphine-based difluorocarbene source is achieved through nucleophilic substitution, and then release of the difluorocarbene through heating. It was believed that this procedure can be ameliorated, by improving the atom economy of the reaction, as well lowering the temperature of release allowing for better use on small scale and in industry. First, the precursors would have the phosphine group swapped for new nitrogen and sulfur-based groups, hopefully allowing for difluorocarbene release at a lower temperature. This was tested by using different types of amines, pyridines and two sulfides. A subset of potential difluorocarbene precursors was thus synthesized. The new difluorocarbene sources were tested in (2+1) cycloaddition reactions and difluoromethylation reactions to test their ability to release the difluorocarbene. The nitrogen-based precursors were tested against the phosphine analogue and showed comparable results. However, all data collected proved that the concept of forming these new difluoroglycine analogues and their reactivity bears potential, but is not fully understood yet. The work presented in this thesis gives key insights into the possibility of synthesizing zwitterionic difluoroglycine analogues and their subsequent reactivity.
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Keywords
difluorocarbene , zwitterionic difluoroglycine-derived difluorocarbene precursors , fluorination