{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/70232"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/70232","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Alpha-Oxygenation by Acylation-Rearrangement of Nitrones","abstract":"The acylation-rearrangement of N-alkylnitrones with acid chlorides and triethylamine affords a new method for the (alpha)-oxygenation of aldehydes and cyclic ketones via (alpha)-acyloxy imines. The reaction apparently proceeds by initial acylation of the nitrone oxygen, proton removal, and {3,3}-sigmatropic rearrangement of the resulting N-vinyl-O-acylhydroxylamine. Oxygen-18 labeling studies in one case showed that no scrambling of the carbonyl oxygens occurs during the rearrangement. Hydrolysis of the product imines provides the (alpha)-acyloxy aldehydes and cyclic ketones. The overall yields for the two- or three step reaction sequence are good, the conditions are quite mild, and the use of electrophilic oxidizing agents is obviated.","abstract_html":"The acylation-rearrangement of N-alkylnitrones with acid chlorides and triethylamine affords a new method for the (alpha)-oxygenation of aldehydes and cyclic ketones via (alpha)-acyloxy imines. The reaction apparently proceeds by initial acylation of the nitrone oxygen, proton removal, and {3,3}-sigmatropic rearrangement of the resulting N-vinyl-O-acylhydroxylamine. Oxygen-18 labeling studies in one case showed that no scrambling of the carbonyl oxygens occurs during the rearrangement. Hydrolysis of the product imines provides the (alpha)-acyloxy aldehydes and cyclic ketones. The overall yields for the two- or three step reaction sequence are good, the conditions are quite mild, and the use of electrophilic oxidizing agents is obviated.","abstract_has_math":false,"creators":["Cummins, Clark Hughes"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Chemistry","degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2014,"date_issued":"2014-12-15T23:18:01Z","date_published":"2014-12-15T23:18:01Z","updated_at":"2026-07-22T22:26:02Z","subjects":["Chemistry, Organic"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["(UMI)AAI8409762"],"render_values":[{"text":"(UMI)AAI8409762","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/70232","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Cummins, Clark Hughes"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2014-12-15T23:18:01Z","10000-01-01","1984"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"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":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Chemistry, Organic"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/70232","(UMI)AAI8409762"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["The acylation-rearrangement of N-alkylnitrones with acid chlorides and triethylamine affords a new method for the (alpha)-oxygenation of aldehydes and cyclic ketones via (alpha)-acyloxy imines. The reaction apparently proceeds by initial acylation of the nitrone oxygen, proton removal, and {3,3}-sigmatropic rearrangement of the resulting N-vinyl-O-acylhydroxylamine. Oxygen-18 labeling studies in one case showed that no scrambling of the carbonyl oxygens occurs during the rearrangement. Hydrolysis of the product imines provides the (alpha)-acyloxy aldehydes and cyclic ketones. The overall yields for the two- or three step reaction sequence are good, the conditions are quite mild, and the use of electrophilic oxidizing agents is obviated.","The stereoselectivity of the acylation-rearrangement was probed by studying the composition of the products obtained from (alpha)-oxygenation of citronellal, 5-norbornene-2-carboxaldehyde and 2-methylcyclohexanecarboxaldehyde. It was found that the rearrangement is only moderately stereoselective, providing nearly equal mixtures of diastereomeric products except for the case of norbornenecarboxaldehyde, which exhibits a strong exo steric bias.","The feasibility of generating nitrone anions was demonstrated by metallation with lithium diisopropylamide followed by silylation. A series of N-vinyl-O-trimethylsilylhydroxylamines was obtained in 35 to 72% yield. Unfortunately, attempts to acylate the nitrone anions or their trimethylsilyl derivatives with acid chlorides provided (alpha)-acyloxy imines in only low yield.","Reduction of the (alpha)-acyloxy imines obtained from acylation-rearrangement of N-tert-butyl and N-cyclohexylnitrones with lithium aluminum hydride affords N-tert-butyl and N-cyclohexylamino alcohols. This approach was not applicable to the synthesis of N-methylamino alcohols, since acylation rearrangement of an N-methylnitrone afforded a mixture of the expected (alpha)-acyloxy imine and an N-methyl imide by-product. Reduction of this mixture with lithium aluminum hydride furnished an inseparable mixture of amino alcohols.","Selective reduction of the carbon-nitrogen double bond of (alpha)-acyloxy imines afforded amino esters, one of which underwent spontaneous oxygen to nitrogen acyl transfer to provide the isomeric amido ester. Sodium borohydride reduction of (alpha)-(methoxycarbonyl)oxy imines, prepared by acylation-rearrangement of nitrones with methyl chloroformate, furnished 2-oxazolidinones. Saponification of an N-methyl-2-oxazolidinone opened a route to N-methylamino alcohols via acylation-rearrangement of nitrones.","Made available in DSpace on 2014-12-15T23:18:01Z (GMT). No. of bitstreams: 1 8409762.pdf: 4513133 bytes, checksum: 6b380aee5187d45776e9d6787c61e691 (MD5) Previous issue date: 1984","Embargo set by: Seth Robbins for item 70398 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","U of I Only","135 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1984."]},{"key":"dc:title","label":"Title","values":["Alpha-Oxygenation by Acylation-Rearrangement of Nitrones"]}]}],"canonical_facts":{"dc:creator":["Cummins, Clark Hughes"],"dc:date":["2014-12-15T23:18:01Z","10000-01-01","1984"],"dc:description":["The acylation-rearrangement of N-alkylnitrones with acid chlorides and triethylamine affords a new method for the (alpha)-oxygenation of aldehydes and cyclic ketones via (alpha)-acyloxy imines. The reaction apparently proceeds by initial acylation of the nitrone oxygen, proton removal, and {3,3}-sigmatropic rearrangement of the resulting N-vinyl-O-acylhydroxylamine. Oxygen-18 labeling studies in one case showed that no scrambling of the carbonyl oxygens occurs during the rearrangement. Hydrolysis of the product imines provides the (alpha)-acyloxy aldehydes and cyclic ketones. The overall yields for the two- or three step reaction sequence are good, the conditions are quite mild, and the use of electrophilic oxidizing agents is obviated.","The stereoselectivity of the acylation-rearrangement was probed by studying the composition of the products obtained from (alpha)-oxygenation of citronellal, 5-norbornene-2-carboxaldehyde and 2-methylcyclohexanecarboxaldehyde. It was found that the rearrangement is only moderately stereoselective, providing nearly equal mixtures of diastereomeric products except for the case of norbornenecarboxaldehyde, which exhibits a strong exo steric bias.","The feasibility of generating nitrone anions was demonstrated by metallation with lithium diisopropylamide followed by silylation. A series of N-vinyl-O-trimethylsilylhydroxylamines was obtained in 35 to 72% yield. Unfortunately, attempts to acylate the nitrone anions or their trimethylsilyl derivatives with acid chlorides provided (alpha)-acyloxy imines in only low yield.","Reduction of the (alpha)-acyloxy imines obtained from acylation-rearrangement of N-tert-butyl and N-cyclohexylnitrones with lithium aluminum hydride affords N-tert-butyl and N-cyclohexylamino alcohols. This approach was not applicable to the synthesis of N-methylamino alcohols, since acylation rearrangement of an N-methylnitrone afforded a mixture of the expected (alpha)-acyloxy imine and an N-methyl imide by-product. Reduction of this mixture with lithium aluminum hydride furnished an inseparable mixture of amino alcohols.","Selective reduction of the carbon-nitrogen double bond of (alpha)-acyloxy imines afforded amino esters, one of which underwent spontaneous oxygen to nitrogen acyl transfer to provide the isomeric amido ester. Sodium borohydride reduction of (alpha)-(methoxycarbonyl)oxy imines, prepared by acylation-rearrangement of nitrones with methyl chloroformate, furnished 2-oxazolidinones. Saponification of an N-methyl-2-oxazolidinone opened a route to N-methylamino alcohols via acylation-rearrangement of nitrones.","Made available in DSpace on 2014-12-15T23:18:01Z (GMT). No. of bitstreams: 1 8409762.pdf: 4513133 bytes, checksum: 6b380aee5187d45776e9d6787c61e691 (MD5) Previous issue date: 1984","Embargo set by: Seth Robbins for item 70398 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","U of I Only","135 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1984."],"dc:identifier":["http://hdl.handle.net/2142/70232","(UMI)AAI8409762"],"dc:subject":["Chemistry, Organic"],"dc:title":["Alpha-Oxygenation by Acylation-Rearrangement of Nitrones"],"dc:type":["text"],"thesis:degree_discipline":["Chemistry"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:26:02Z"}