{"id":{"repo_id":"aachen","oai_identifier":"oai:publications.rwth-aachen.de:61714"},"canonical_url":"https://search.dev.ndltd.org/etd/aachen/oai:publications.rwth-aachen.de:61714","repository":{"repo_id":"aachen","name":"RWTH Aachen University","base_url":"https://publications.rwth-aachen.de/oai2d"},"display":{"title":"Methoden zur asymmetrischen nucleophilen Glyoxylierung","abstract":"Chiral alpha-ketoacids and their derivatives play an important role in organic synthesis and are widely used as inhibitors of both proteolytic enzymes as well as inhibitors of leukotriene A4 hydrolase. Furthermore they are an integral part of important biologically active ulosonic- and sialic acids. Because of the presence of an beta-enolisable asymmetric centre, the number of methods leading to enantioenriched alpha-ketoesters are rather limited. New and efficient synthetic approaches as a solution to this problem are therefore of high interest. This thesis deals with the application of chiral and racemic glyoxylate aminonitriles in developing both a stoichiometric as an organocatalytic procedure for the synthesis of beta-substituted alpha-ketoesters. This could be realised by applying the concept of Umpolung, which enables the nucleophilic introduction of the alpha-ketoacid system. The use of chiral glyoxylate aminonitriles in the Michael addition to nitroalkenes and subsequent cleavage of the aminonitrile group led to the corresponding gamma-nitro-alpha-ketoesters in high enantiomeric excesses. An asymmetric organocatalytic approach to protected beta-substituted delta-hydroxy-alpha-ketoesters with good enantio- and diastereoselectivities could be realised in the presence of a diphenylprolinol catalyst.","abstract_html":"Chiral alpha-ketoacids and their derivatives play an important role in organic synthesis and are widely used as inhibitors of both proteolytic enzymes as well as inhibitors of leukotriene A4 hydrolase. Furthermore they are an integral part of important biologically active ulosonic- and sialic acids. Because of the presence of an beta-enolisable asymmetric centre, the number of methods leading to enantioenriched alpha-ketoesters are rather limited. New and efficient synthetic approaches as a solution to this problem are therefore of high interest. This thesis deals with the application of chiral and racemic glyoxylate aminonitriles in developing both a stoichiometric as an organocatalytic procedure for the synthesis of beta-substituted alpha-ketoesters. This could be realised by applying the concept of Umpolung, which enables the nucleophilic introduction of the alpha-ketoacid system. The use of chiral glyoxylate aminonitriles in the Michael addition to nitroalkenes and subsequent cleavage of the aminonitrile group led to the corresponding gamma-nitro-alpha-ketoesters in high enantiomeric excesses. An asymmetric organocatalytic approach to protected beta-substituted delta-hydroxy-alpha-ketoesters with good enantio- and diastereoselectivities could be realised in the presence of a diphenylprolinol catalyst.","abstract_has_math":false,"creators":["Bonten, Maurice Hubert"],"institution":"Mainz","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":["Enders, Dieter"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2007,"date_issued":"2007","date_published":"2007","updated_at":"2026-07-30T19:43:10Z","subjects":["info:eu-repo/classification/ddc/540","Aminonitrile","Asymmetrische Synthese","Katalyse","Oxocarbonsäureester","Michael-Addition","Chemie","Organokatalyse","Glyoxylierung","Glyoxylat-Aminonitril","chirale Amine","organocatalysis","glyoxylation","glyoxylate aminonitrile","chiral amines"],"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-123349%22"],"render_values":[{"text":"https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-123349%22","href":"https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-123349%22","code":true}]}]},"links":{"outbound_url":"https://publications.rwth-aachen.de/record/61714","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":["Bonten, Maurice Hubert"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:coverage","label":"Dc Coverage","values":["DE"]},{"key":"dc:date","label":"Dc Date","values":["2007"]},{"key":"dc:publisher","label":"Institution","values":["Mainz"]},{"key":"dc:relation","label":"Dc Relation","values":["info:eu-repo/semantics/altIdentifier/urn/urn:nbn:de:hbz:82-opus-18501","info:eu-repo/semantics/altIdentifier/isbn/3-86130-556-9"]},{"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","Aminonitrile","Asymmetrische Synthese","Katalyse","Oxocarbonsäureester","Michael-Addition","Chemie","Organokatalyse","Glyoxylierung","Glyoxylat-Aminonitril","chirale Amine","organocatalysis","glyoxylation","glyoxylate aminonitrile","chiral amines"]}]},{"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/61714","https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-123349%22"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Chiral alpha-ketoacids and their derivatives play an important role in organic synthesis and are widely used as inhibitors of both proteolytic enzymes as well as inhibitors of leukotriene A4 hydrolase. Furthermore they are an integral part of important biologically active ulosonic- and sialic acids. Because of the presence of an beta-enolisable asymmetric centre, the number of methods leading to enantioenriched alpha-ketoesters are rather limited. New and efficient synthetic approaches as a solution to this problem are therefore of high interest. This thesis deals with the application of chiral and racemic glyoxylate aminonitriles in developing both a stoichiometric as an organocatalytic procedure for the synthesis of beta-substituted alpha-ketoesters. This could be realised by applying the concept of Umpolung, which enables the nucleophilic introduction of the alpha-ketoacid system. The use of chiral glyoxylate aminonitriles in the Michael addition to nitroalkenes and subsequent cleavage of the aminonitrile group led to the corresponding gamma-nitro-alpha-ketoesters in high enantiomeric excesses. An asymmetric organocatalytic approach to protected beta-substituted delta-hydroxy-alpha-ketoesters with good enantio- and diastereoselectivities could be realised in the presence of a diphenylprolinol catalyst."]},{"key":"dc:source","label":"Dc Source","values":["Aachen : Mainz, Aachener Beiträge zur Chemie 74, III, 144 S. (2007). = Zugl.: Aachen, Techn. Hochsch., Diss., 2007"]},{"key":"dc:title","label":"Title","values":["Methoden zur asymmetrischen nucleophilen Glyoxylierung"]}]}],"canonical_facts":{"dc:contributor":["Enders, Dieter"],"dc:coverage":["DE"],"dc:creator":["Bonten, Maurice Hubert"],"dc:date":["2007"],"dc:description":["Chiral alpha-ketoacids and their derivatives play an important role in organic synthesis and are widely used as inhibitors of both proteolytic enzymes as well as inhibitors of leukotriene A4 hydrolase. Furthermore they are an integral part of important biologically active ulosonic- and sialic acids. Because of the presence of an beta-enolisable asymmetric centre, the number of methods leading to enantioenriched alpha-ketoesters are rather limited. New and efficient synthetic approaches as a solution to this problem are therefore of high interest. This thesis deals with the application of chiral and racemic glyoxylate aminonitriles in developing both a stoichiometric as an organocatalytic procedure for the synthesis of beta-substituted alpha-ketoesters. This could be realised by applying the concept of Umpolung, which enables the nucleophilic introduction of the alpha-ketoacid system. The use of chiral glyoxylate aminonitriles in the Michael addition to nitroalkenes and subsequent cleavage of the aminonitrile group led to the corresponding gamma-nitro-alpha-ketoesters in high enantiomeric excesses. An asymmetric organocatalytic approach to protected beta-substituted delta-hydroxy-alpha-ketoesters with good enantio- and diastereoselectivities could be realised in the presence of a diphenylprolinol catalyst."],"dc:identifier":["https://publications.rwth-aachen.de/record/61714","https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-123349%22"],"dc:language":["ger"],"dc:publisher":["Mainz"],"dc:relation":["info:eu-repo/semantics/altIdentifier/urn/urn:nbn:de:hbz:82-opus-18501","info:eu-repo/semantics/altIdentifier/isbn/3-86130-556-9"],"dc:rights":["info:eu-repo/semantics/openAccess"],"dc:source":["Aachen : Mainz, Aachener Beiträge zur Chemie 74, III, 144 S. (2007). = Zugl.: Aachen, Techn. 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