Publication Date

2024

Document Type

Dissertation/Thesis

First Advisor

Klumpp, Douglas A.

Degree Name

Ph.D. (Doctor of Philosophy)

Legacy Department

Department of Chemistry and Biochemistry

Abstract

Aromatic spirocycles are crucial organic scaffolds that are at the forefront of innovation in various fields of organic electronics, as well as in drug design. The synthesis of these compounds is challenging, especially on an industrial scale and often have suboptimal yields in many traditional syntheses. New synthetic methodologies are being continually explored for the installation of sp3 hydridized spiro junctions. Our research group, as well as other groups, have done exploration of using superelectrophilic synthetic routes that are nicely applied to the formation of aromatic spirocycles. Most relevant to the results discussed in this dissertation are condensation chemistry using hydroxyalkylation reactions with sufficiently electrophilic carbonyls, and with Friedel-Crafts reactions with fluorenyl cations. These concepts are summarized in Chapter 1.

Chapter 2: Biaryl ethers condense directly with carbonyl groups on diazafluorenones, acenaphthenequinone, and isatins to give a variety of spirocyclic compounds. The condensation reactions are promoted by the Brønsted superacid, triflic acid (CF3SO3H). This methodology provides a convenient one-pot synthetic route to aromatic spirocycles in good to quantitative yields.

Chapter 3: A variety of imidazole and benzimidazole-containing spirobifluorene analogues have been prepared via intramolecular Friedel-Crafts reaction. The condensation reactions are promoted using the Brønsted superacid, triflic acid (CF3SO3H). This methodology consistently provides very high yields within 24 hours without the need for heating. A mechanism is proposed involving dicationic intermediates. The precursor fluorenyl alcohol is synthesized from deprotonation of the N-aryl imidazoles and reaction with various fluorenones. Electrochemical and optical calculations of frontier molecular orbital levels were carried out. Fluorescence spectroscopy showed that select conjugated fluorophores were emissive in the near-UV visible (blue-purple) spectrum range.

Chapter 4: A variety of spirocycle and spirocycle adjacent syntheses were attempted. While some compounds were successfully synthesized, all of the project ideas contained in this chapter were ultimately deemed not worthy of continuing to pursue at the time. This material is included for future reference of those who may want to work on similar projects.

Extent

264 pages

Language

en

Publisher

Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

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