{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/21192"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/21192","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Diastereoselectivity of the metallo-enamine condensation; addition and cyclization reactions of vinyl isocyanates","abstract":"The diastereoselectivity of the metallo-enamine condensation was examined using a variety of imines and aldehydes. The highest selectivity (5:95, anti:syn) was observed in the reaction of the lithium enamine of propylidene-t-butylamine with pivaldehyde. Therefore, high diastereoselectivities can be achieved through the use of aldehyde derivatives, although with lithium, sterically hindered substituents on both the imine nitrogen and on the aldehyde are required. A non-chelated transition state is proposed to account for the formation of the syn product from the ($E$)-metallo-enamine. Reduction of the intermediate alkoxide was developed as a way to prepare 1,3-amino alcohols and to avoid the risk of epimerization of the hydroxy imines. The use of other metals was examined. Titanium provided high levels of syn selectivity in all reactions ($<$10:90 in most cases), regardless of the size of the substituents although the yields were moderate (20-66%). An octahedral titanium complex is invoked to explain the observed results. Metallo-enamine condensations with zirconium, zinc, boron, and tin were nonselective. Hauser's work on the condensations of amide enolate anions with aldehydes was repeated and was found to be in error owing to the solubility of the minor isomer in the aqueous phase. The reactions were not exclusively anti selective, as reported, but instead provided hydroxy amides in ratios of 63:37 and 78:22. Imidate anions were also nonselective.","abstract_html":"The diastereoselectivity of the metallo-enamine condensation was examined using a variety of imines and aldehydes. The highest selectivity (5:95, anti:syn) was observed in the reaction of the lithium enamine of propylidene-t-butylamine with pivaldehyde. Therefore, high diastereoselectivities can be achieved through the use of aldehyde derivatives, although with lithium, sterically hindered substituents on both the imine nitrogen and on the aldehyde are required. A non-chelated transition state is proposed to account for the formation of the syn product from the ($E$)-metallo-enamine. Reduction of the intermediate alkoxide was developed as a way to prepare 1,3-amino alcohols and to avoid the risk of epimerization of the hydroxy imines. The use of other metals was examined. Titanium provided high levels of syn selectivity in all reactions ($&lt;$10:90 in most cases), regardless of the size of the substituents although the yields were moderate (20-66%). An octahedral titanium complex is invoked to explain the observed results. Metallo-enamine condensations with zirconium, zinc, boron, and tin were nonselective. Hauser&#x27;s work on the condensations of amide enolate anions with aldehydes was repeated and was found to be in error owing to the solubility of the minor isomer in the aqueous phase. The reactions were not exclusively anti selective, as reported, but instead provided hydroxy amides in ratios of 63:37 and 78:22. Imidate anions were also nonselective.","abstract_has_math":true,"creators":["Wolk, Diane Ridout"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Chemistry","degree_department":null,"school":null,"contributors":["Coates, Robert M."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-05-07T13:01:11Z","date_published":"2011-05-07T13:01:11Z","updated_at":"2026-07-22T22:25:17Z","subjects":["Chemistry, Organic"],"languages":["eng"],"rights":["Copyright 1990 Wolk, Diane Ridout"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI9026354","(UMI)AAI9026354"],"render_values":[{"text":"AAI9026354","href":null,"code":true},{"text":"(UMI)AAI9026354","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/21192","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Coates, Robert M."]},{"key":"dc:creator","label":"Author","values":["Wolk, Diane Ridout"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-05-07T13:01:11Z","10000-01-01","1990"]},{"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":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 1990 Wolk, Diane Ridout"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI9026354","(UMI)AAI9026354","http://hdl.handle.net/2142/21192"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["The diastereoselectivity of the metallo-enamine condensation was examined using a variety of imines and aldehydes. The highest selectivity (5:95, anti:syn) was observed in the reaction of the lithium enamine of propylidene-t-butylamine with pivaldehyde. Therefore, high diastereoselectivities can be achieved through the use of aldehyde derivatives, although with lithium, sterically hindered substituents on both the imine nitrogen and on the aldehyde are required. A non-chelated transition state is proposed to account for the formation of the syn product from the ($E$)-metallo-enamine. Reduction of the intermediate alkoxide was developed as a way to prepare 1,3-amino alcohols and to avoid the risk of epimerization of the hydroxy imines. The use of other metals was examined. Titanium provided high levels of syn selectivity in all reactions ($<$10:90 in most cases), regardless of the size of the substituents although the yields were moderate (20-66%). An octahedral titanium complex is invoked to explain the observed results. Metallo-enamine condensations with zirconium, zinc, boron, and tin were nonselective. Hauser's work on the condensations of amide enolate anions with aldehydes was repeated and was found to be in error owing to the solubility of the minor isomer in the aqueous phase. The reactions were not exclusively anti selective, as reported, but instead provided hydroxy amides in ratios of 63:37 and 78:22. Imidate anions were also nonselective.","The reactions of carbonyl compounds with cyclohexenyl, cyclopentenyl, and styryl isocyanates were investigated. Although no reaction occurred with dried ethyl glyoxylate, ethyl glyoxylate hydrates provided a $\\beta$-hydroxy ketone, presumably through the N-vinyl carbamic acid. The formation of a cyclic carbamate was found to be limited to diethyl oxomalonate in the presence of titanium tetrachloride. Addition of alkyl Grignard and alkyllithium reagents to cyclohexenyl isocyanate afforded a series of N-cyclohexenyl amides. Thermal and photochemical cyclizations of these enamides was also carried out. Cyclic amides were formed by photochemical electrocyclization along with $\\beta$-amino ketones arising through photo-Fries rearrangement.","Made available in DSpace on 2011-05-07T13:01:11Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9026354.pdf: 6020100 bytes, checksum: 2ba16a91d618393b1988127521765806 (MD5) Previous issue date: 1990","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:49:06Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:22:18-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission","ETDs are only available to UIUC Users without author permission","U of I Only"]},{"key":"dc:title","label":"Title","values":["Diastereoselectivity of the metallo-enamine condensation; addition and cyclization reactions of vinyl isocyanates"]}]}],"canonical_facts":{"dc:contributor":["Coates, Robert M."],"dc:creator":["Wolk, Diane Ridout"],"dc:date":["2011-05-07T13:01:11Z","10000-01-01","1990"],"dc:description":["The diastereoselectivity of the metallo-enamine condensation was examined using a variety of imines and aldehydes. The highest selectivity (5:95, anti:syn) was observed in the reaction of the lithium enamine of propylidene-t-butylamine with pivaldehyde. Therefore, high diastereoselectivities can be achieved through the use of aldehyde derivatives, although with lithium, sterically hindered substituents on both the imine nitrogen and on the aldehyde are required. A non-chelated transition state is proposed to account for the formation of the syn product from the ($E$)-metallo-enamine. Reduction of the intermediate alkoxide was developed as a way to prepare 1,3-amino alcohols and to avoid the risk of epimerization of the hydroxy imines. The use of other metals was examined. Titanium provided high levels of syn selectivity in all reactions ($<$10:90 in most cases), regardless of the size of the substituents although the yields were moderate (20-66%). An octahedral titanium complex is invoked to explain the observed results. Metallo-enamine condensations with zirconium, zinc, boron, and tin were nonselective. Hauser's work on the condensations of amide enolate anions with aldehydes was repeated and was found to be in error owing to the solubility of the minor isomer in the aqueous phase. The reactions were not exclusively anti selective, as reported, but instead provided hydroxy amides in ratios of 63:37 and 78:22. Imidate anions were also nonselective.","The reactions of carbonyl compounds with cyclohexenyl, cyclopentenyl, and styryl isocyanates were investigated. Although no reaction occurred with dried ethyl glyoxylate, ethyl glyoxylate hydrates provided a $\\beta$-hydroxy ketone, presumably through the N-vinyl carbamic acid. The formation of a cyclic carbamate was found to be limited to diethyl oxomalonate in the presence of titanium tetrachloride. Addition of alkyl Grignard and alkyllithium reagents to cyclohexenyl isocyanate afforded a series of N-cyclohexenyl amides. Thermal and photochemical cyclizations of these enamides was also carried out. Cyclic amides were formed by photochemical electrocyclization along with $\\beta$-amino ketones arising through photo-Fries rearrangement.","Made available in DSpace on 2011-05-07T13:01:11Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9026354.pdf: 6020100 bytes, checksum: 2ba16a91d618393b1988127521765806 (MD5) Previous issue date: 1990","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:49:06Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:22:18-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission","ETDs are only available to UIUC Users without author permission","U of I Only"],"dc:identifier":["AAI9026354","(UMI)AAI9026354","http://hdl.handle.net/2142/21192"],"dc:language":["eng"],"dc:rights":["Copyright 1990 Wolk, Diane Ridout"],"dc:subject":["Chemistry, Organic"],"dc:title":["Diastereoselectivity of the metallo-enamine condensation; addition and cyclization reactions of vinyl isocyanates"],"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":"2026-07-22T22:25:17Z"}