{"id":{"repo_id":"wvu","oai_identifier":"oai:researchrepository.wvu.edu:etd-2598"},"canonical_url":"https://search.dev.ndltd.org/etd/wvu/oai:researchrepository.wvu.edu:etd-2598","repository":{"repo_id":"wvu","name":"West Virginia University","base_url":"https://researchrepository.wvu.edu/do/oai/"},"display":{"title":"Preparation of benzoenyne -allenes, enyne -isocyanates and enyne -carbodiimides and their applications in the synthesis of polycyclic aromatic hydrocarbons and heterocycles","abstract":"The thionyl chloride-induced cascade cyclization of enediynyl propargylic alcohols provides an efficient synthetic route to 11H-benzo[ b]fluoren-11-ols and related compounds. The simplicity of the synthetic sequence and the mildness of the reaction condition make this pathway especially attractive. Interestingly, in certain cases the intramolecular [2+2] cycloaddition reaction of the chlorinated benzoenyne-allene intermediates occurred preferentially to form 1H-cyclobut[a]indenes. Competition from the intramolecular [2+2] cycloaddition reaction could be avoided with the non-chlorinated benzoenyne-allenes, providing direct access to novel polycyclic aromatic hydrocarbons. Several indeno-fused 4,5-diarylphenanrenes were synthesized by a consecutive C2-C6 cyclization of a symmetrical benzoenyne-allene. The formal Diels-Alder reaction involving a C2-C6 cyclization reaction followed by a radical-radical coupling reaction of the benzannulated enyne-allenes is key to the efficient assembly of the phenanthrene system. The buttressing effects due to the indeno-fused rings and the two tert-butyl groups at the 1- and 8-positions are responsible for increasing the activation barrier for the helix inversion of the resulting 4,5-diarylphenanthrenes.;Thermolysis of enyne-isocyanates represents a new way of generating biradicals and/or zwitterions from unsaturated molecules having nitrogen and oxygen atom in the conjugated system. Due to the ring strain, cycloaromatization of cyclopentene-based enyne-isocyanates and enyne-carbodiimides underwent predominately C 2-C7 cyclization pathway. The existence of intramolecular decay routes for the initially formed biradicals or zwitterions made these cyclization reactions essentially useful, leading to a variety of polycyclic heterocycles.","abstract_html":"The thionyl chloride-induced cascade cyclization of enediynyl propargylic alcohols provides an efficient synthetic route to 11H-benzo[ b]fluoren-11-ols and related compounds. The simplicity of the synthetic sequence and the mildness of the reaction condition make this pathway especially attractive. Interestingly, in certain cases the intramolecular [2+2] cycloaddition reaction of the chlorinated benzoenyne-allene intermediates occurred preferentially to form 1H-cyclobut[a]indenes. Competition from the intramolecular [2+2] cycloaddition reaction could be avoided with the non-chlorinated benzoenyne-allenes, providing direct access to novel polycyclic aromatic hydrocarbons. Several indeno-fused 4,5-diarylphenanrenes were synthesized by a consecutive C2-C6 cyclization of a symmetrical benzoenyne-allene. The formal Diels-Alder reaction involving a C2-C6 cyclization reaction followed by a radical-radical coupling reaction of the benzannulated enyne-allenes is key to the efficient assembly of the phenanthrene system. The buttressing effects due to the indeno-fused rings and the two tert-butyl groups at the 1- and 8-positions are responsible for increasing the activation barrier for the helix inversion of the resulting 4,5-diarylphenanthrenes.;Thermolysis of enyne-isocyanates represents a new way of generating biradicals and/or zwitterions from unsaturated molecules having nitrogen and oxygen atom in the conjugated system. Due to the ring strain, cycloaromatization of cyclopentene-based enyne-isocyanates and enyne-carbodiimides underwent predominately C 2-C7 cyclization pathway. The existence of intramolecular decay routes for the initially formed biradicals or zwitterions made these cyclization reactions essentially useful, leading to a variety of polycyclic heterocycles.","abstract_has_math":false,"creators":["Li, Hongbin"],"institution":null,"degree_name":"PhD","degree_level":"Dissertation","degree_discipline":"Chemistry","degree_department":null,"school":null,"contributors":["Kung K. Wang."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2002,"date_issued":"2002-05-01T07:00:00Z","date_published":"2002-05-01T07:00:00Z","updated_at":"2026-07-24T06:15:55Z","subjects":["Organic chemistry"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["https://researchrepository.wvu.edu/etd/1595"],"render_values":[{"text":"https://researchrepository.wvu.edu/etd/1595","href":"https://researchrepository.wvu.edu/etd/1595","code":true}]}]},"links":{"outbound_url":"https://doi.org/10.33915/etd.1595","outbound_label":"DOI","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Kung K. Wang."]},{"key":"dc:creator","label":"Author","values":["Li, Hongbin"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.available","label":"Dc Date Available","values":["2019-01-17T08:00:00Z"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Chemistry"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["PhD"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Organic chemistry"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://doi.org/10.33915/etd.1595","https://researchrepository.wvu.edu/etd/1595"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["The thionyl chloride-induced cascade cyclization of enediynyl propargylic alcohols provides an efficient synthetic route to 11H-benzo[ b]fluoren-11-ols and related compounds. The simplicity of the synthetic sequence and the mildness of the reaction condition make this pathway especially attractive. Interestingly, in certain cases the intramolecular [2+2] cycloaddition reaction of the chlorinated benzoenyne-allene intermediates occurred preferentially to form 1H-cyclobut[a]indenes. Competition from the intramolecular [2+2] cycloaddition reaction could be avoided with the non-chlorinated benzoenyne-allenes, providing direct access to novel polycyclic aromatic hydrocarbons. Several indeno-fused 4,5-diarylphenanrenes were synthesized by a consecutive C2-C6 cyclization of a symmetrical benzoenyne-allene. The formal Diels-Alder reaction involving a C2-C6 cyclization reaction followed by a radical-radical coupling reaction of the benzannulated enyne-allenes is key to the efficient assembly of the phenanthrene system. The buttressing effects due to the indeno-fused rings and the two tert-butyl groups at the 1- and 8-positions are responsible for increasing the activation barrier for the helix inversion of the resulting 4,5-diarylphenanthrenes.;Thermolysis of enyne-isocyanates represents a new way of generating biradicals and/or zwitterions from unsaturated molecules having nitrogen and oxygen atom in the conjugated system. Due to the ring strain, cycloaromatization of cyclopentene-based enyne-isocyanates and enyne-carbodiimides underwent predominately C 2-C7 cyclization pathway. The existence of intramolecular decay routes for the initially formed biradicals or zwitterions made these cyclization reactions essentially useful, leading to a variety of polycyclic heterocycles."]},{"key":"dc:title","label":"Title","values":["Preparation of benzoenyne -allenes, enyne -isocyanates and enyne -carbodiimides and their applications in the synthesis of polycyclic aromatic hydrocarbons and heterocycles"]}]}],"canonical_facts":{"dc:contributor":["Kung K. Wang."],"dc:creator":["Li, Hongbin"],"dc:date.available":["2019-01-17T08:00:00Z"],"dc:description.abstract":["The thionyl chloride-induced cascade cyclization of enediynyl propargylic alcohols provides an efficient synthetic route to 11H-benzo[ b]fluoren-11-ols and related compounds. The simplicity of the synthetic sequence and the mildness of the reaction condition make this pathway especially attractive. Interestingly, in certain cases the intramolecular [2+2] cycloaddition reaction of the chlorinated benzoenyne-allene intermediates occurred preferentially to form 1H-cyclobut[a]indenes. Competition from the intramolecular [2+2] cycloaddition reaction could be avoided with the non-chlorinated benzoenyne-allenes, providing direct access to novel polycyclic aromatic hydrocarbons. Several indeno-fused 4,5-diarylphenanrenes were synthesized by a consecutive C2-C6 cyclization of a symmetrical benzoenyne-allene. The formal Diels-Alder reaction involving a C2-C6 cyclization reaction followed by a radical-radical coupling reaction of the benzannulated enyne-allenes is key to the efficient assembly of the phenanthrene system. The buttressing effects due to the indeno-fused rings and the two tert-butyl groups at the 1- and 8-positions are responsible for increasing the activation barrier for the helix inversion of the resulting 4,5-diarylphenanthrenes.;Thermolysis of enyne-isocyanates represents a new way of generating biradicals and/or zwitterions from unsaturated molecules having nitrogen and oxygen atom in the conjugated system. Due to the ring strain, cycloaromatization of cyclopentene-based enyne-isocyanates and enyne-carbodiimides underwent predominately C 2-C7 cyclization pathway. The existence of intramolecular decay routes for the initially formed biradicals or zwitterions made these cyclization reactions essentially useful, leading to a variety of polycyclic heterocycles."],"dc:identifier":["https://doi.org/10.33915/etd.1595","https://researchrepository.wvu.edu/etd/1595"],"dc:subject":["Organic chemistry"],"dc:title":["Preparation of benzoenyne -allenes, enyne -isocyanates and enyne -carbodiimides and their applications in the synthesis of polycyclic aromatic hydrocarbons and heterocycles"],"thesis:degree_discipline":["Chemistry"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["PhD"]},"updated_at":"2026-07-24T06:15:55Z"}