{"id":{"repo_id":"mit","oai_identifier":"oai:dspace.mit.edu:1721.1/17739"},"canonical_url":"https://search.dev.ndltd.org/etd/mit/oai:dspace.mit.edu:1721.1/17739","repository":{"repo_id":"mit","name":"MIT","base_url":"https://dspace.mit.edu/oai/request"},"display":{"title":"Mechanistic and synthetic studies of the intramolecular [4+2] cycloaddition of conjugated enynes","abstract":"An examination of the mechanism and scope of the intramolecular [4+2] cycloaddition of conjugated enynes has shown the reaction likely proceeds by a concerted cycloaddition of the enyne to give a highly reactive cyclic allene intermediate which isomerizes to aromatic and dihydroaromatic compounds through proton transfer or hydrogen atom transfer mechanisms. Studies of the intramolecular cycloaddition of conjugated arylacetylenes (arenynes) indicated that these compounds may react by a stepwise annulation mechanism involving biradical intermediates. An investigation of the use of protic solvents has shown that alcohols, in particular 2,2,2-trifluoroethanol, can significantly improve the isolated yield of products. The application of strained cyclic acetylenes, specifically arynes generated by a modification of the Kobayashi protocol with tetrabutylammonium triphenyldifluorosilicate (TBAT), has been shown to efficiently provide cycloaddition products with substituted enynes, arenynes, and hetarenynes at room temperature.","abstract_html":"An examination of the mechanism and scope of the intramolecular [4+2] cycloaddition of conjugated enynes has shown the reaction likely proceeds by a concerted cycloaddition of the enyne to give a highly reactive cyclic allene intermediate which isomerizes to aromatic and dihydroaromatic compounds through proton transfer or hydrogen atom transfer mechanisms. Studies of the intramolecular cycloaddition of conjugated arylacetylenes (arenynes) indicated that these compounds may react by a stepwise annulation mechanism involving biradical intermediates. An investigation of the use of protic solvents has shown that alcohols, in particular 2,2,2-trifluoroethanol, can significantly improve the isolated yield of products. The application of strained cyclic acetylenes, specifically arynes generated by a modification of the Kobayashi protocol with tetrabutylammonium triphenyldifluorosilicate (TBAT), has been shown to efficiently provide cycloaddition products with substituted enynes, arenynes, and hetarenynes at room temperature.","abstract_has_math":false,"creators":["Hayes, Martin Elliott, 1974-"],"institution":"Massachusetts Institute of Technology","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":"Massachusetts Institute of Technology. Dept. of Chemistry.","school":null,"contributors":[],"advisors":["Rick L. Danheiser."],"committee_chairs":[],"committee_members":[],"year":2004,"date_issued":"2004","date_published":"2004","updated_at":"2026-07-22T22:22:18Z","subjects":["Chemistry."],"languages":["eng"],"rights":["M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission."],"rights_urls":["http://dspace.mit.edu/handle/1721.1/7582"],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/1721.1/17739","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Rick L. Danheiser."]},{"key":"dc:contributor.department","label":"Department","values":["Massachusetts Institute of Technology. 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The application of strained cyclic acetylenes, specifically arynes generated by a modification of the Kobayashi protocol with tetrabutylammonium triphenyldifluorosilicate (TBAT), has been shown to efficiently provide cycloaddition products with substituted enynes, arenynes, and hetarenynes at room temperature."]},{"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":["Mechanistic and synthetic studies of the intramolecular [4+2] cycloaddition of conjugated enynes"]}]}],"canonical_facts":{"dc:contributor.advisor":["Rick L. Danheiser."],"dc:contributor.department":["Massachusetts Institute of Technology. Dept. of Chemistry."],"dc:contributor.other":["Massachusetts Institute of Technology. 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An investigation of the use of protic solvents has shown that alcohols, in particular 2,2,2-trifluoroethanol, can significantly improve the isolated yield of products. The application of strained cyclic acetylenes, specifically arynes generated by a modification of the Kobayashi protocol with tetrabutylammonium triphenyldifluorosilicate (TBAT), has been shown to efficiently provide cycloaddition products with substituted enynes, arenynes, and hetarenynes at room temperature."],"dc:description.degree":["Ph.D."],"dc:format.mimetype":["application/pdf"],"dc:identifier.uri":["http://hdl.handle.net/1721.1/17739"],"dc:language.iso":["eng"],"dc:publisher":["Massachusetts Institute of Technology"],"dc:rights":["M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission."],"dc:rights.uri":["http://dspace.mit.edu/handle/1721.1/7582"],"dc:subject":["Chemistry."],"dc:title":["Mechanistic and synthetic studies of the intramolecular [4+2] cycloaddition of conjugated enynes"],"dc:type":["Thesis"]},"updated_at":"2026-07-22T22:22:18Z"}