{"id":{"repo_id":"aachen","oai_identifier":"oai:publications.rwth-aachen.de:61791"},"canonical_url":"https://search.dev.ndltd.org/etd/aachen/oai:publications.rwth-aachen.de:61791","repository":{"repo_id":"aachen","name":"RWTH Aachen University","base_url":"https://publications.rwth-aachen.de/oai2d"},"display":{"title":"Asymmetrische Synthese von hoch substituierten delta -Lactonen : Synthese der Prelactone B und V, von Simplacton B und von Massoialacton","abstract":"The asymmetric syntheses of prelactone B und V, simplactone B, massoialactone and of related Delta-lactones were carried out in this work. The RAMP-hydrazone of 2,2-dimethyl-1,3-dioxan-5-one was chosen as starting material for the synthesis of the 4-hydroxy-5,6-alkyl and 4-hydroxy-5-alkyl substituted lactones (prelactones und simplacton B). Key step of this six step synthesis was the hydrogenation of the exo-cyclic double bond of the precursor using homogeneous catalysts. The reduction of the unsaturated lactones using Crabtree´s catalyst led to the desired products, with the right relative configuration (all substituents in trans-position). If Wilkinson´s catalyst was used for the hydrogenation of the precursor of prelactone B, the selective formation of the 5-epimer of prelactone B was observed. The synthesis of (R)-massoialactone could also be achieved starting from the RAMP-hydrazone of 2,2-dimethyl-1,3-dioxan-5-one. The desired carboxyl-functionality was generated via a methylfurfuryl substituent and the deoxygenation of the Alpha,Alpha´-disubstituted dioxanones was carried out using the Barton-McCombie-protocol.","abstract_html":"The asymmetric syntheses of prelactone B und V, simplactone B, massoialactone and of related Delta-lactones were carried out in this work. The RAMP-hydrazone of 2,2-dimethyl-1,3-dioxan-5-one was chosen as starting material for the synthesis of the 4-hydroxy-5,6-alkyl and 4-hydroxy-5-alkyl substituted lactones (prelactones und simplacton B). Key step of this six step synthesis was the hydrogenation of the exo-cyclic double bond of the precursor using homogeneous catalysts. The reduction of the unsaturated lactones using Crabtree´s catalyst led to the desired products, with the right relative configuration (all substituents in trans-position). If Wilkinson´s catalyst was used for the hydrogenation of the precursor of prelactone B, the selective formation of the 5-epimer of prelactone B was observed. The synthesis of (R)-massoialactone could also be achieved starting from the RAMP-hydrazone of 2,2-dimethyl-1,3-dioxan-5-one. The desired carboxyl-functionality was generated via a methylfurfuryl substituent and the deoxygenation of the Alpha,Alpha´-disubstituted dioxanones was carried out using the Barton-McCombie-protocol.","abstract_has_math":false,"creators":["Job, Mareile"],"institution":"Publikationsserver der RWTH Aachen University","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":["Enders, Dieter"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2005,"date_issued":"2005","date_published":"2005","updated_at":"2026-07-30T19:43:19Z","subjects":["info:eu-repo/classification/ddc/540","Tetrahydropyranonderivate","Asymmetrische Synthese","Hydrazon-Methode","Chemie","Prelactone","SAMP/RAMP-Methode","Naturstoffsynthese"],"languages":["ger"],"rights":["info:eu-repo/semantics/openAccess"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-123415%22"],"render_values":[{"text":"https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-123415%22","href":"https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-123415%22","code":true}]}]},"links":{"outbound_url":"https://publications.rwth-aachen.de/record/61791","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Enders, Dieter"]},{"key":"dc:creator","label":"Author","values":["Job, Mareile"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:coverage","label":"Dc Coverage","values":["DE"]},{"key":"dc:date","label":"Dc Date","values":["2005"]},{"key":"dc:publisher","label":"Institution","values":["Publikationsserver der RWTH Aachen University"]},{"key":"dc:relation","label":"Dc Relation","values":["info:eu-repo/semantics/altIdentifier/urn/urn:nbn:de:hbz:82-opus-11402"]},{"key":"dc:type","label":"Dc Type","values":["info:eu-repo/semantics/doctoralThesis","info:eu-repo/semantics/publishedVersion"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["info:eu-repo/classification/ddc/540","Tetrahydropyranonderivate","Asymmetrische Synthese","Hydrazon-Methode","Chemie","Prelactone","SAMP/RAMP-Methode","Naturstoffsynthese"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["ger"]},{"key":"dc:rights","label":"Dc Rights","values":["info:eu-repo/semantics/openAccess"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://publications.rwth-aachen.de/record/61791","https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-123415%22"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["The asymmetric syntheses of prelactone B und V, simplactone B, massoialactone and of related Delta-lactones were carried out in this work. The RAMP-hydrazone of 2,2-dimethyl-1,3-dioxan-5-one was chosen as starting material for the synthesis of the 4-hydroxy-5,6-alkyl and 4-hydroxy-5-alkyl substituted lactones (prelactones und simplacton B). Key step of this six step synthesis was the hydrogenation of the exo-cyclic double bond of the precursor using homogeneous catalysts. The reduction of the unsaturated lactones using Crabtree´s catalyst led to the desired products, with the right relative configuration (all substituents in trans-position). If Wilkinson´s catalyst was used for the hydrogenation of the precursor of prelactone B, the selective formation of the 5-epimer of prelactone B was observed. The synthesis of (R)-massoialactone could also be achieved starting from the RAMP-hydrazone of 2,2-dimethyl-1,3-dioxan-5-one. The desired carboxyl-functionality was generated via a methylfurfuryl substituent and the deoxygenation of the Alpha,Alpha´-disubstituted dioxanones was carried out using the Barton-McCombie-protocol."]},{"key":"dc:source","label":"Dc Source","values":["Aachen : Publikationsserver der RWTH Aachen University II, 205 S. : graph. Darst. (2005). = Aachen, Techn. Hochsch., Diss., 2005"]},{"key":"dc:title","label":"Title","values":["Asymmetrische Synthese von hoch substituierten delta -Lactonen : Synthese der Prelactone B und V, von Simplacton B und von Massoialacton"]}]}],"canonical_facts":{"dc:contributor":["Enders, Dieter"],"dc:coverage":["DE"],"dc:creator":["Job, Mareile"],"dc:date":["2005"],"dc:description":["The asymmetric syntheses of prelactone B und V, simplactone B, massoialactone and of related Delta-lactones were carried out in this work. The RAMP-hydrazone of 2,2-dimethyl-1,3-dioxan-5-one was chosen as starting material for the synthesis of the 4-hydroxy-5,6-alkyl and 4-hydroxy-5-alkyl substituted lactones (prelactones und simplacton B). Key step of this six step synthesis was the hydrogenation of the exo-cyclic double bond of the precursor using homogeneous catalysts. The reduction of the unsaturated lactones using Crabtree´s catalyst led to the desired products, with the right relative configuration (all substituents in trans-position). If Wilkinson´s catalyst was used for the hydrogenation of the precursor of prelactone B, the selective formation of the 5-epimer of prelactone B was observed. The synthesis of (R)-massoialactone could also be achieved starting from the RAMP-hydrazone of 2,2-dimethyl-1,3-dioxan-5-one. The desired carboxyl-functionality was generated via a methylfurfuryl substituent and the deoxygenation of the Alpha,Alpha´-disubstituted dioxanones was carried out using the Barton-McCombie-protocol."],"dc:identifier":["https://publications.rwth-aachen.de/record/61791","https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-123415%22"],"dc:language":["ger"],"dc:publisher":["Publikationsserver der RWTH Aachen University"],"dc:relation":["info:eu-repo/semantics/altIdentifier/urn/urn:nbn:de:hbz:82-opus-11402"],"dc:rights":["info:eu-repo/semantics/openAccess"],"dc:source":["Aachen : Publikationsserver der RWTH Aachen University II, 205 S. : graph. Darst. (2005). = Aachen, Techn. 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