Doctor of Philosophy
Michael A. Kerr
The first chapter of this thesis describes two projects, one explores the novel reactivity of quaternary donor acceptor cyclopropanes and the second one involves progress toward the total synthesis of the flinderoles A, B, and C. The first project involves the Lewis acid catalyzed nucleophilic ring opening of quaternary donor acceptor cyclopropanes with indoline. It was found that the ring opening reaction worked well with either Sc(OTf)3 or Yb(OTf)3 as the Lewis acids. The ring opened products were also able to be converted into pyrroloindoles via a manganese (III) oxidative radical cyclization reaction. Cyclopropanes bearing alkynyl, vinyl, and aryl substituents were well tolerated as well as indolines bearing substitution at the 3-position. The second project involves the application of the ring opening/cyclization reaction to synthesize the pyrroloindole scaffold of the flinderoles. The chapter also describes our efforts to complete the synthesis of the natural products, and despite many alternative routes, we were not able to access the flinderoles.
The second chapter describes the Lewis acid catalyzed annulation reactions of donor acceptor cyclopropanes with vinyl azide and 2H-azirine. Surprisingly, the reaction with either the vinyl azide or 2H-azirine gave the same azabicyclic product. The reaction was also limited to cyclopropanes bearing trifluoroethyl esters instead of the common methyl esters. The reaction scope with respect to the cyclopropanes tolerated aryl, heteroaryl, vinyl, alkynyl and quaternary substituents on the cyclopropane. In both reactions, the azabicycle was obtained as a single diastereomer, which was confirmed by x-ray crystallography.
Curiel Tejeda, Joanne E., "Synthesis of N-Heterocycles from Donor Acceptor Cyclopropanes and Progress towards Flinderole A, B, and C" (2017). Electronic Thesis and Dissertation Repository. 4908.