{"id":{"repo_id":"texas","oai_identifier":"oai:repositories.lib.utexas.edu:2152/2659"},"canonical_url":"https://search.dev.ndltd.org/etd/texas/oai:repositories.lib.utexas.edu:2152/2659","repository":{"repo_id":"texas","name":"University of Texas","base_url":"https://repositories.lib.utexas.edu/server/oai/request"},"display":{"title":"Stereospecific alkynylation at the more hindered carbon of trisubstituted epoxides and concise syntheses of bis-THF acetogenins and analogues","abstract":"Alkynyl aluminate reagents react cleanly at the tertiary position of trisubstituted epoxides in 75-80% isolated yield. The reaction is stereospecific with inversion at the substitution center. This work constitutes the first general method for the addition of a carbon nucleophile at the more congested site of a trisubstituted epoxide. The less efficient alkynyl alane reagents for the same transformation were also discussed. Bis-THF acetogenin bullatacin and analogues are each synthesized in 22 steps and 6.2% overall yield. The new synthesis takes a modular approach and features a cobalt mediated oxidative cyclization reaction, an efficient synthesis of epoxy butenolide, and a highly diastereoselective alkylation of a bis-THF aldehyde. The efficiency of the new synthetic sequence allows quick assembly of the series of compounds and the study of their structure and activity relationships (SARs) is currently underway.","abstract_html":"Alkynyl aluminate reagents react cleanly at the tertiary position of trisubstituted epoxides in 75-80% isolated yield. The reaction is stereospecific with inversion at the substitution center. This work constitutes the first general method for the addition of a carbon nucleophile at the more congested site of a trisubstituted epoxide. The less efficient alkynyl alane reagents for the same transformation were also discussed. Bis-THF acetogenin bullatacin and analogues are each synthesized in 22 steps and 6.2% overall yield. The new synthesis takes a modular approach and features a cobalt mediated oxidative cyclization reaction, an efficient synthesis of epoxy butenolide, and a highly diastereoselective alkylation of a bis-THF aldehyde. The efficiency of the new synthetic sequence allows quick assembly of the series of compounds and the study of their structure and activity relationships (SARs) is currently underway.","abstract_has_math":false,"creators":["Zhao, Hongda"],"institution":"The University of Texas at Austin","degree_name":"Doctor of Philosophy","degree_level":"Doctoral","degree_discipline":"Chemistry","degree_department":null,"school":null,"contributors":[],"advisors":["Pagenkopf, Brian L."],"committee_chairs":[],"committee_members":[],"year":2006,"date_issued":"2006","date_published":"2006","updated_at":"2026-07-24T05:01:24Z","subjects":[],"languages":["eng"],"rights":["Copyright is held by the author. 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The less efficient alkynyl alane reagents for the same transformation were also discussed. Bis-THF acetogenin bullatacin and analogues are each synthesized in 22 steps and 6.2% overall yield. The new synthesis takes a modular approach and features a cobalt mediated oxidative cyclization reaction, an efficient synthesis of epoxy butenolide, and a highly diastereoselective alkylation of a bis-THF aldehyde. 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Presentation of this material on the Libraries' web site by University Libraries, The University of Texas at Austin was made possible under a limited license grant from the author who has retained all copyrights in the works."],"dc:title":["Stereospecific alkynylation at the more hindered carbon of trisubstituted epoxides and concise syntheses of bis-THF acetogenins and analogues"],"thesis:degree_discipline":["Chemistry"],"thesis:degree_level":["Doctoral"],"thesis:degree_name":["Doctor of Philosophy"],"thesis:institution_name":["The University of Texas at Austin"]},"updated_at":"2026-07-24T05:01:24Z"}