Synthesis and rearrangements of vinylcyclopropanes in a [2+3] cyclopentene and oxycyclopentene annulation methodology approach to (-)- specionin

dc.contributor.authorFleming, Alison A.en
dc.contributor.committeechairHudlicky, Tomasen
dc.contributor.committeememberWolfe, James F.en
dc.contributor.committeememberMason, John G.en
dc.contributor.committeememberTanko, James M.en
dc.contributor.committeememberWhite, Robert H.en
dc.description.abstractThe addition of lithium dienolate 130, formed from ethyl 2-bromocrotonate, to enones and aldehydes yielding vinylcyclopropanes and vinyloxiranes was optimized. Various methods, pyrolytic and nonpyrolytic, were examined for the rearrangement of the resulting vinylcyclopropanes to cyclopentenes in an overall [2+3] annulation sequence. During the course of these studies, a new rearrangement pathway of these vinylcyclopropanes to bridged [3.2.n] bicyclic systems was discovered thus establishing a new [3+4] annulation technology. The extension of the [2+3] annulation technology to oxygenated cyclopentanoids was addressed. Several ethyl 2-bromo-4-oxycrotonates were synthesized, and the reaction of their lithium dienolates (217) with enones was investigated. The rearrangement of the resulting enol ether terminated vinylcyclopropanes to oxygenated cyclopentenes was also examined. [see document for diagram of chemical reaction] The application of this methodology was expressed in a synthetic approach to (-)-specionin (109). The key steps in this synthesis involved the cyclopropanation of optically pure enone 147 with Iithium dienolate 155 to give vinylcyclopropanes 169-exo/endo and the rearrangement of 169 to the oxygenated cyclopentanoid 187-exo which possesses the correct stereochemistry for further elaboration to epoxy acetate 216, an intermediate in a reported synthesis of specionin. [see document for diagrams of chemical reactions]en
dc.description.degreePh. D.en
dc.format.extentvi, 171 leavesen
dc.publisherVirginia Polytechnic Institute and State Universityen
dc.relation.isformatofOCLC# 21063568en
dc.rightsIn Copyrighten
dc.subject.lccLD5655.V856 1989.F647en
dc.subject.lcshCyclopropane -- Researchen
dc.subject.lcshSpecionin -- Synthesisen
dc.titleSynthesis and rearrangements of vinylcyclopropanes in a [2+3] cyclopentene and oxycyclopentene annulation methodology approach to (-)- specioninen
dc.type.dcmitypeTexten Polytechnic Institute and State Universityen D.en


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