{"id":{"repo_id":"houston","oai_identifier":"oai:uh-ir.tdl.org:10657/20907"},"canonical_url":"https://search.dev.ndltd.org/etd/houston/oai:uh-ir.tdl.org:10657/20907","repository":{"repo_id":"houston","name":"University of Houston","base_url":"https://uh-ir.tdl.org/server/oai/request"},"display":{"title":"Cascade Transformations in Organic Synthesis: I. The Interception of Carbene Alkyne Metathesis Intermediates II. Photo-Activation of Hydrazones III. Organocatalyzed Cascade Conjugate Addition/Aldol Annulation of Organoboronates","abstract":"This dissertation describes cascade transformations in constructing complex building blocks in synthetic organic chemistry. It includes the interceptions of carbene alkyne metathesis intermediates, boron enolate intermediates, fused cyclopropene intermediates, and boronic acid intermediates. First, the multi-alkyne carbene cascade reaction under rhodium catalysis is discussed. Ten different diazoesters were synthesized and tested for cascade reactions. This transformation proved to be limited, since it only works for super engineered structures. It also reveals the possibility that carbene alkyne metathesis might be reversible. In the second chapter, a 1,5-triazole initiated carbene cascade reaction was discovered. A cyclopropene rearrangement mechanism converts those triazoles to spiro-1,3-enynes. Several different termination pathways were designed to achieve the formal 6-exo-dig and formal 7-endo-dig cyclization. Third, a light-promoted Barluenga-Valdés coupling was developed. Many different diarylalkanes and triarylboronates could be synthesized via this strategy. The mechanism of hydrazone decomposition via visible light was carefully elucidated. An organocatalyzed tandem conjugate addition/Aldol annulation of organoboronates was discussed in the last chapter. A variety of nucleophiles showed good compatibility with heterocycles. In addition, the strength of boron enolate intermediates were examined by intercepting with various electrophiles.","abstract_html":"This dissertation describes cascade transformations in constructing complex building blocks in synthetic organic chemistry. It includes the interceptions of carbene alkyne metathesis intermediates, boron enolate intermediates, fused cyclopropene intermediates, and boronic acid intermediates. First, the multi-alkyne carbene cascade reaction under rhodium catalysis is discussed. Ten different diazoesters were synthesized and tested for cascade reactions. This transformation proved to be limited, since it only works for super engineered structures. It also reveals the possibility that carbene alkyne metathesis might be reversible. In the second chapter, a 1,5-triazole initiated carbene cascade reaction was discovered. A cyclopropene rearrangement mechanism converts those triazoles to spiro-1,3-enynes. Several different termination pathways were designed to achieve the formal 6-exo-dig and formal 7-endo-dig cyclization. Third, a light-promoted Barluenga-Valdés coupling was developed. Many different diarylalkanes and triarylboronates could be synthesized via this strategy. The mechanism of hydrazone decomposition via visible light was carefully elucidated. An organocatalyzed tandem conjugate addition/Aldol annulation of organoboronates was discussed in the last chapter. A variety of nucleophiles showed good compatibility with heterocycles. In addition, the strength of boron enolate intermediates were examined by intercepting with various electrophiles.","abstract_has_math":false,"creators":["Dong, Zhencheng 1997-"],"institution":"University of Houston","degree_name":"Doctor of Philosophy","degree_level":null,"degree_discipline":"Chemistry","degree_department":null,"school":null,"contributors":[],"advisors":["May, Jeremy A."],"committee_chairs":[],"committee_members":["Daugulis, Olafs","Scott, Gilbertson","Statsyuk, Alexander V.","Teets, Thomas"],"year":2025,"date_issued":"2025-12","date_published":"2025-12","updated_at":"2026-07-24T02:32:54Z","subjects":["Carbene Alkyne Metathesis","Organoboronates","Barluenga-Valés Coupling","Cyclopropene Rearrangement","C-H insertion","Enantioselective Conjugate Addition","Indanols","Aldol Reaction","Light Induced Hydrazone Decomposition"],"languages":["English"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/10657/20907","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["May, Jeremy A."]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Daugulis, Olafs","Scott, Gilbertson","Statsyuk, Alexander V.","Teets, Thomas"]},{"key":"dc:creator","label":"Author","values":["Dong, Zhencheng 1997-"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2026-02-09T19:17:14Z"]},{"key":"dc:date.issued","label":"Date","values":["2025-12"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Chemistry"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Doctor of Philosophy"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Houston"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Carbene Alkyne Metathesis","Organoboronates","Barluenga-Valés Coupling","Cyclopropene Rearrangement","C-H insertion","Enantioselective Conjugate Addition","Indanols","Aldol Reaction","Light Induced Hydrazone Decomposition"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["English"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/10657/20907"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["This dissertation describes cascade transformations in constructing complex building blocks in synthetic organic chemistry. It includes the interceptions of carbene alkyne metathesis intermediates, boron enolate intermediates, fused cyclopropene intermediates, and boronic acid intermediates. First, the multi-alkyne carbene cascade reaction under rhodium catalysis is discussed. Ten different diazoesters were synthesized and tested for cascade reactions. This transformation proved to be limited, since it only works for super engineered structures. It also reveals the possibility that carbene alkyne metathesis might be reversible. In the second chapter, a 1,5-triazole initiated carbene cascade reaction was discovered. A cyclopropene rearrangement mechanism converts those triazoles to spiro-1,3-enynes. Several different termination pathways were designed to achieve the formal 6-exo-dig and formal 7-endo-dig cyclization. Third, a light-promoted Barluenga-Valdés coupling was developed. Many different diarylalkanes and triarylboronates could be synthesized via this strategy. The mechanism of hydrazone decomposition via visible light was carefully elucidated. An organocatalyzed tandem conjugate addition/Aldol annulation of organoboronates was discussed in the last chapter. A variety of nucleophiles showed good compatibility with heterocycles. In addition, the strength of boron enolate intermediates were examined by intercepting with various electrophiles."]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Cascade Transformations in Organic Synthesis: I. The Interception of Carbene Alkyne Metathesis Intermediates II. Photo-Activation of Hydrazones III. Organocatalyzed Cascade Conjugate Addition/Aldol Annulation of Organoboronates"]}]}],"canonical_facts":{"dc:contributor.advisor":["May, Jeremy A."],"dc:contributor.committeemember":["Daugulis, Olafs","Scott, Gilbertson","Statsyuk, Alexander V.","Teets, Thomas"],"dc:creator":["Dong, Zhencheng 1997-"],"dc:date.accessioned":["2026-02-09T19:17:14Z"],"dc:date.issued":["2025-12"],"dc:description.abstract":["This dissertation describes cascade transformations in constructing complex building blocks in synthetic organic chemistry. It includes the interceptions of carbene alkyne metathesis intermediates, boron enolate intermediates, fused cyclopropene intermediates, and boronic acid intermediates. First, the multi-alkyne carbene cascade reaction under rhodium catalysis is discussed. Ten different diazoesters were synthesized and tested for cascade reactions. This transformation proved to be limited, since it only works for super engineered structures. It also reveals the possibility that carbene alkyne metathesis might be reversible. In the second chapter, a 1,5-triazole initiated carbene cascade reaction was discovered. A cyclopropene rearrangement mechanism converts those triazoles to spiro-1,3-enynes. Several different termination pathways were designed to achieve the formal 6-exo-dig and formal 7-endo-dig cyclization. Third, a light-promoted Barluenga-Valdés coupling was developed. Many different diarylalkanes and triarylboronates could be synthesized via this strategy. The mechanism of hydrazone decomposition via visible light was carefully elucidated. An organocatalyzed tandem conjugate addition/Aldol annulation of organoboronates was discussed in the last chapter. A variety of nucleophiles showed good compatibility with heterocycles. In addition, the strength of boron enolate intermediates were examined by intercepting with various electrophiles."],"dc:format.mimetype":["application/pdf"],"dc:identifier.uri":["https://hdl.handle.net/10657/20907"],"dc:language.iso":["English"],"dc:subject":["Carbene Alkyne Metathesis","Organoboronates","Barluenga-Valés Coupling","Cyclopropene Rearrangement","C-H insertion","Enantioselective Conjugate Addition","Indanols","Aldol Reaction","Light Induced Hydrazone Decomposition"],"dc:title":["Cascade Transformations in Organic Synthesis: I. The Interception of Carbene Alkyne Metathesis Intermediates II. Photo-Activation of Hydrazones III. Organocatalyzed Cascade Conjugate Addition/Aldol Annulation of Organoboronates"],"dc:type":["Thesis"],"thesis:degree_discipline":["Chemistry"],"thesis:degree_name":["Doctor of Philosophy"],"thesis:institution_name":["University of Houston"]},"updated_at":"2026-07-24T02:32:54Z"}