Document Type

Dissertation

Degree

Doctor of Philosophy

Major

Chemistry, Organic

Date of Defense

11-3-2022

Graduate Advisor

Eike B. Bauer

Committee

Eike B. Bauer

Alexei V. Demchenko

Keith J. Stine

Janet B. Wilking

Abstract

Organic synthesis has been significantly advanced with the employment of transition metal complexes. The discovery of transition metal catalysts provided the synthetic community with powerful tools for accelerating reactions and making them more selective and efficient. Many chemical reactions do not happen without a catalyst.

Iron-based catalysts have several advantages for the chemical industry because it is a non-toxic and ecologically friendly metal. Our group previously found that ferrocenium cations with a 3+ oxidation state of iron-catalyzed propargylic substitution reactions at low temperatures. The sandwich structure of ferrocenes allows substituents to be introduced on the cyclopentadienyl rings, which allows for catalyst tuning. Ferrocenium cations can act as mild- Lewis acids.

The first aim of the study was to investigate ferrocenium cations as catalysts in etherification reactions of propargylic alcohols, which are frequently utilized as starting materials in organic synthesis. Direct substitution of a hydroxyl unit with an alcohol nucleophile will afford a propargylic ether product. We synthesized three different propargylic alcohols to investigate catalyst performance and the reaction mechanism. Ferrocenium hexafluorophosphate and ferrocenium boronic acid hexafluoroantimonate were initially utilized as catalysts. We found out that the ferrocenium salts were catalytically active and that the reaction proceeds through an ionic mechanism.

Carbohydrates are important biomolecules playing pivotal roles in many cellular processes. Glycosylation is a key step to chemically synthesize oligo- and polysaccharides. In the second aim of the research, ferrocenium salts were utilized to obtain a glycosidic bond between a glycosyl donor and a glycosyl acceptor. Glycosyl donors with different leaving groups were investigated, discovering that glycosyl chlorides and fluorides performed well as donors.

Sepsis, an infectious disorder, can result in multiple organ dysfunction. Curcumin, a natural compound found in the spice turmeric, has been widely studied for its anti-inflammatory property. However, it is not widely used due to its poor water solubility and bioavailability. To increase the solubility and bioavailability of curcumin, we modified its structure. Under aim 3, several glycosylated curcumin derivatives were synthesized. They showed increased solubility and stability; their physiological activity is currently under investigation in other research groups in the chemistry department.

Download

Share

COinS