{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/23622"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/23622","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Rearrangements and biogenetic relationships of silphinane sesquiterpenes","abstract":"Acid-catalyzed rearrangement of presilphiperfolanol to silphiperfol-6-ene and $\\alpha$-terrecyclene formed by way of a silphinyl ion intermediate, suggests that the presilphiperfolanyl carbocation could be an important intermediate and a branch point in the biogenesis of triquinane sesquiterpenes such as silphiperfol-6-ene, silphinene, and related compounds.","abstract_html":"Acid-catalyzed rearrangement of presilphiperfolanol to silphiperfol-6-ene and <span class=\"etd-inline-math\">&alpha;</span>-terrecyclene formed by way of a silphinyl ion intermediate, suggests that the presilphiperfolanyl carbocation could be an important intermediate and a branch point in the biogenesis of triquinane sesquiterpenes such as silphiperfol-6-ene, silphinene, and related compounds.","abstract_has_math":true,"creators":["Ho, Jonathan Zhanqi"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Chemistry, Organic","degree_department":null,"school":null,"contributors":["Coates, Robert M."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-05-07T14:20:57Z","date_published":"2011-05-07T14:20:57Z","updated_at":"2026-07-22T22:25:22Z","subjects":["Chemistry, Organic"],"languages":["eng"],"rights":["Copyright 1996 Ho, Jonathan Zhanqi"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["9780591198966","AAI9712306","(UMI)AAI9712306"],"render_values":[{"text":"9780591198966","href":null,"code":true},{"text":"AAI9712306","href":null,"code":true},{"text":"(UMI)AAI9712306","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/23622","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Coates, Robert M."]},{"key":"dc:creator","label":"Author","values":["Ho, Jonathan Zhanqi"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-05-07T14:20:57Z","10000-01-01","1996"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Chemistry, Organic"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Chemistry, Organic"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 1996 Ho, Jonathan Zhanqi"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["9780591198966","AAI9712306","(UMI)AAI9712306","http://hdl.handle.net/2142/23622"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Acid-catalyzed rearrangement of presilphiperfolanol to silphiperfol-6-ene and $\\alpha$-terrecyclene formed by way of a silphinyl ion intermediate, suggests that the presilphiperfolanyl carbocation could be an important intermediate and a branch point in the biogenesis of triquinane sesquiterpenes such as silphiperfol-6-ene, silphinene, and related compounds.","The absolute configuration of the tricyclic sesquiterpene alcohol ($-$)-presilphiperfolanol, structural precursor for the angular and propellane triquinane sesquiterpenes, was established by correlation with ($-$)-silphiperfol-6-ene. The relative stereochemistry of this alcohol was previously determined in this laboratory by an X-ray crystallographic analysis of its p-nitrobenzoate derivative.","Solvolytic rearrangement both silphin-1$\\alpha$-yl and 1$\\beta$-yl methanesulfonates gave not only the previously reported tricyclic bridgehead alcohol and $\\alpha$-terrecyclene by Wagner-Meerwein rearrangement products, but also isocomene and modhephene sesquiterpene natural products as minor rearrangement products arising by an initial competing 1,3-hydride shift. Exclusive rearrangement of the interannular bond occurred, and no products arising from migration of the peripheral cyclopentyl bond were detected. The large (ca. 10$\\sp3$) rate enhancement for solvolysis of silphin-1$\\alpha$-yl methanesulfonate over its epimer is consistent with C-7,C-8 bond participation in the transition state for the 1$\\alpha$-isomer. $\\alpha$-Terrecyclene has the same (4.3.2.0$\\sp{1,5}$) undecane carbon skeleton ring system as the antibiotic quadrone and terrecyclic acid natural products. Thus, it is possible that silphinyl carbocation is another branch point in the biogenesis of sesquiterpenes such as isocomene, modhephene, quadrone and related compounds.","Made available in DSpace on 2011-05-07T14:20:57Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9712306.pdf: 6805103 bytes, checksum: c05966a38066da5eb9bfc66d1d275790 (MD5) Previous issue date: 1996","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T15:05:43Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:31:31-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission","ETDs are only available to UIUC Users without author permission","U of I Only"]},{"key":"dc:title","label":"Title","values":["Rearrangements and biogenetic relationships of silphinane sesquiterpenes"]}]}],"canonical_facts":{"dc:contributor":["Coates, Robert M."],"dc:creator":["Ho, Jonathan Zhanqi"],"dc:date":["2011-05-07T14:20:57Z","10000-01-01","1996"],"dc:description":["Acid-catalyzed rearrangement of presilphiperfolanol to silphiperfol-6-ene and $\\alpha$-terrecyclene formed by way of a silphinyl ion intermediate, suggests that the presilphiperfolanyl carbocation could be an important intermediate and a branch point in the biogenesis of triquinane sesquiterpenes such as silphiperfol-6-ene, silphinene, and related compounds.","The absolute configuration of the tricyclic sesquiterpene alcohol ($-$)-presilphiperfolanol, structural precursor for the angular and propellane triquinane sesquiterpenes, was established by correlation with ($-$)-silphiperfol-6-ene. The relative stereochemistry of this alcohol was previously determined in this laboratory by an X-ray crystallographic analysis of its p-nitrobenzoate derivative.","Solvolytic rearrangement both silphin-1$\\alpha$-yl and 1$\\beta$-yl methanesulfonates gave not only the previously reported tricyclic bridgehead alcohol and $\\alpha$-terrecyclene by Wagner-Meerwein rearrangement products, but also isocomene and modhephene sesquiterpene natural products as minor rearrangement products arising by an initial competing 1,3-hydride shift. Exclusive rearrangement of the interannular bond occurred, and no products arising from migration of the peripheral cyclopentyl bond were detected. The large (ca. 10$\\sp3$) rate enhancement for solvolysis of silphin-1$\\alpha$-yl methanesulfonate over its epimer is consistent with C-7,C-8 bond participation in the transition state for the 1$\\alpha$-isomer. $\\alpha$-Terrecyclene has the same (4.3.2.0$\\sp{1,5}$) undecane carbon skeleton ring system as the antibiotic quadrone and terrecyclic acid natural products. Thus, it is possible that silphinyl carbocation is another branch point in the biogenesis of sesquiterpenes such as isocomene, modhephene, quadrone and related compounds.","Made available in DSpace on 2011-05-07T14:20:57Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9712306.pdf: 6805103 bytes, checksum: c05966a38066da5eb9bfc66d1d275790 (MD5) Previous issue date: 1996","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T15:05:43Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:31:31-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission","ETDs are only available to UIUC Users without author permission","U of I Only"],"dc:identifier":["9780591198966","AAI9712306","(UMI)AAI9712306","http://hdl.handle.net/2142/23622"],"dc:language":["eng"],"dc:rights":["Copyright 1996 Ho, Jonathan Zhanqi"],"dc:subject":["Chemistry, Organic"],"dc:title":["Rearrangements and biogenetic relationships of silphinane sesquiterpenes"],"dc:type":["text"],"thesis:degree_discipline":["Chemistry, Organic"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:25:22Z"}