Date of Award
Doctor of Philosophy
George A. Kraus
Methyl coumalate is a bio-renewable material derived from malic acid. In the first chapter, we focused on the Diels-Alder reaction of methyl coumalate with a variety of dienophiles, including enamines, magnesium salts of indoles and hydroxyquinones. Some provided the bicyclic lactone intermediates, which could be further transformed into aromatic esters by acid/base catalyzed ring opening reactions. Others went through a Diels-Alder/retro Diels-Alder cascade and the carbon dioxide was extruded, affording the corresponding products. As a result, isophthalates, naphthalates and anthraquinone derivatives were successfully synthesized according to this strategy. The natural product Tomichaedin was also synthesized in over 40% yield.
In the second chapter, we have developed a method to in situ generate nitroquinone, and a variety of nucleophiles were tested for the conjugate addition. Substituted nitroquinones can be synthesized in moderate yield via a 1,4-addition – tautomerization cascade. Nucleophiles including indoles, electron rich aromatics and heterocycles all showed good reactivity. Additionally, a divergent synthesis towards Lagumycin and Phenathroviridone skeleton was proposed.
Yu, Huangchao, "Biorenewable chemicals in organic synthesis: Applications of methyl coumalate and nitroquinones" (2019). Graduate Theses and Dissertations. 17624.