{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/54358"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/54358","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Synthesis and rearrangements of vinylcyclopropanes in a [2+3] cyclopentene and oxycyclopentene annulation methodology approach to (-)- specionin","abstract":"The 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]","abstract_html":"The 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]","abstract_has_math":false,"creators":["Fleming, Alison A."],"institution":"Virginia Polytechnic Institute and State University","degree_name":"Ph. D.","degree_level":"doctoral","degree_discipline":"Chemistry","degree_department":"Chemistry","school":null,"contributors":[],"advisors":[],"committee_chairs":["Hudlicky, Tomas"],"committee_members":["Wolfe, James F.","Mason, John G.","Tanko, James M.","White, Robert H."],"year":1989,"date_issued":"1989","date_published":"1989","updated_at":"2026-07-22T22:20:20Z","subjects":[],"languages":["en_US"],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/10919/54358","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["Hudlicky, Tomas"]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Wolfe, James F.","Mason, John G.","Tanko, James M.","White, Robert H."]},{"key":"dc:contributor.department","label":"Department","values":["Chemistry"]},{"key":"dc:creator","label":"Author","values":["Fleming, Alison A."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2015-07-09T20:43:50Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2015-07-09T20:43:50Z"]},{"key":"dc:date.issued","label":"Date","values":["1989"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Polytechnic Institute and State University"]},{"key":"dc:type","label":"Dc Type","values":["Dissertation"]},{"key":"dc:type.dcmitype","label":"Dc Type Dcmitype","values":["Text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Chemistry"]},{"key":"thesis:degree_level","label":"Degree Level","values":["doctoral"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph. 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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]"]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Ph. D."]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Synthesis and rearrangements of vinylcyclopropanes in a [2+3] cyclopentene and oxycyclopentene annulation methodology approach to (-)- specionin"]}]}],"canonical_facts":{"dc:contributor.committeechair":["Hudlicky, Tomas"],"dc:contributor.committeemember":["Wolfe, James F.","Mason, John G.","Tanko, James M.","White, Robert H."],"dc:contributor.department":["Chemistry"],"dc:creator":["Fleming, Alison A."],"dc:date.accessioned":["2015-07-09T20:43:50Z"],"dc:date.available":["2015-07-09T20:43:50Z"],"dc:date.issued":["1989"],"dc:description.abstract":["The 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]"],"dc:description.degree":["Ph. D."],"dc:format.mimetype":["application/pdf"],"dc:identifier.uri":["http://hdl.handle.net/10919/54358"],"dc:language.iso":["en_US"],"dc:publisher":["Virginia Polytechnic Institute and State University"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:title":["Synthesis and rearrangements of vinylcyclopropanes in a [2+3] cyclopentene and oxycyclopentene annulation methodology approach to (-)- specionin"],"dc:type":["Dissertation"],"dc:type.dcmitype":["Text"],"thesis:degree_discipline":["Chemistry"],"thesis:degree_level":["doctoral"],"thesis:degree_name":["Ph. D."],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:20:20Z"}