{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/70379"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/70379","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Synthesis and Claisen Rearrangement of Alpha-Ethoxyallyl Vinyl Ethers. Evidence for a Dipolar Transition State","abstract":"The product stereoselectivity, scope, and mechanism of the Claisen-Micheal reaction (8 $\\rightarrow$ 11) were explored. The products (e.g. 11) of the Claisen-Micheal reaction, which are enol ethers, are protected equivalents of the adducts obtained from the Micheal reaction of $\\alpha,\\beta$-enals with activated carbonyl compounds.$$\\vbox{\\vskip72pt}$$==>>>","abstract_html":"The product stereoselectivity, scope, and mechanism of the Claisen-Micheal reaction (8 $\\rightarrow$ 11) were explored. The products (e.g. 11) of the Claisen-Micheal reaction, which are enol ethers, are protected equivalents of the adducts obtained from the Micheal reaction of α,β-enals with activated carbonyl compounds.$$\\vbox{\\vskip72pt}$$==>>>","abstract_has_math":true,"creators":["Rogers, Brian Daniel"],"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":1987,"date_issued":"1987","date_published":"1987","updated_at":"2026-07-22T22:26:02Z","subjects":["Chemistry, Organic"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["(UMI)AAI8721744"],"render_values":[{"text":"(UMI)AAI8721744","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/70379","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Rogers, Brian Daniel"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["1987","2014-12-15T23:19:01Z","10000-01-01"]},{"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/2142/70379","(UMI)AAI8721744"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["The product stereoselectivity, scope, and mechanism of the Claisen-Micheal reaction (8 $\\rightarrow$ 11) were explored. The products (e.g. 11) of the Claisen-Micheal reaction, which are enol ethers, are protected equivalents of the adducts obtained from the Micheal reaction of $\\alpha,\\beta$-enals with activated carbonyl compounds.$$\\vbox{\\vskip72pt}$$==>>>","The enolate anions of ethyl 2-methylacetoacetate, 2-carbethoxycylopentanone, 2-carbethoxycyclohexanone, 2-cyanocyclopentanone, and 2-cyanocylohexanone underwent O -alkylation in the THF containing polar cosolvents with $\\alpha$-chloro-$\\beta$-(arylseleno)alkyl ethyl ethers to produce 2-(arylseleno)alkanal vinyl ethyl acetals (e.g. 8). Oxidation of the seleno acetals with 1 equiv of m -chloroperoxybenzoic acid in dichloromethane at $-40 \\rightarrow 0\\sp\\circ{\\rm C}$ provided 2-(3-ethoxyallyl) active carbonyl compounds (e.g. 11) directly. The mechanism of the rearrangement probably involves a Claisen rearrangement of the intermediate $\\alpha$-ethoxyallyl vinyl ether (e.g. 10).","The oxidation of the seleno acetal derived from cyclopentanone (Z = H) gave the putative intermediate $\\alpha$-ethoxyallyl cyclopentenyl ether (45) in 18% yield. The Claisen rearrangement of 45 was found to occur 159 and 2560 times faster than cyclopentenyl allyl ether (47) in benzene-d$\\sb6$ and 80% aqueous ethanol-d$\\sb6$, respectively. The significant substituent and solvent effects provide experimental evidence for a pronounced dipolar character of the transition state. Further ($>$45 fold) acceleration of the rearrangements from the combined influence of a 4-ethoxy group and a cyano or carbethoxy group at C-1 indicates a synergistic interaction of the donor and acceptor substituents.","The product stereoselectivity of the selenoxide fragmentation was examined by oxidation of 2-(phenylseleno)butyraldehyde diethyl acetal (56) which provided crotonaldehyde diethyl acetal (57) as an 87:13 (E: Z) mixture. Oxidation of various 2-(arylseleno)butyraldehyde vinyl ethyl acetals showed the product stereoselectivity (with respect to diastereomers produced as a result of the formation of contiguous chiral centers via rearrangement) of the overall process (8 $\\rightarrow$ 11) to vary between 88:12 (considered to be a stereoselective rearrangement) and 63:37 (ca. 34% stereoselectivity). The lack of consistent product stereoselectivity is believed to result from a high degree of C-4/O-3 bond cleavage in the transition state which reduces the free energy difference between the chair and boat transition states.","Made available in DSpace on 2014-12-15T23:19:01Z (GMT). No. of bitstreams: 1 8721744.pdf: 4567106 bytes, checksum: cd676a1dc8eb6a78bcc1618efbef4ce9 (MD5) Previous issue date: 1987","Embargo set by: Seth Robbins for item 70545 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","148 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1987."]},{"key":"dc:title","label":"Title","values":["Synthesis and Claisen Rearrangement of Alpha-Ethoxyallyl Vinyl Ethers. Evidence for a Dipolar Transition State"]}]}],"canonical_facts":{"dc:creator":["Rogers, Brian Daniel"],"dc:date":["1987","2014-12-15T23:19:01Z","10000-01-01"],"dc:description":["The product stereoselectivity, scope, and mechanism of the Claisen-Micheal reaction (8 $\\rightarrow$ 11) were explored. The products (e.g. 11) of the Claisen-Micheal reaction, which are enol ethers, are protected equivalents of the adducts obtained from the Micheal reaction of $\\alpha,\\beta$-enals with activated carbonyl compounds.$$\\vbox{\\vskip72pt}$$==>>>","The enolate anions of ethyl 2-methylacetoacetate, 2-carbethoxycylopentanone, 2-carbethoxycyclohexanone, 2-cyanocyclopentanone, and 2-cyanocylohexanone underwent O -alkylation in the THF containing polar cosolvents with $\\alpha$-chloro-$\\beta$-(arylseleno)alkyl ethyl ethers to produce 2-(arylseleno)alkanal vinyl ethyl acetals (e.g. 8). Oxidation of the seleno acetals with 1 equiv of m -chloroperoxybenzoic acid in dichloromethane at $-40 \\rightarrow 0\\sp\\circ{\\rm C}$ provided 2-(3-ethoxyallyl) active carbonyl compounds (e.g. 11) directly. The mechanism of the rearrangement probably involves a Claisen rearrangement of the intermediate $\\alpha$-ethoxyallyl vinyl ether (e.g. 10).","The oxidation of the seleno acetal derived from cyclopentanone (Z = H) gave the putative intermediate $\\alpha$-ethoxyallyl cyclopentenyl ether (45) in 18% yield. The Claisen rearrangement of 45 was found to occur 159 and 2560 times faster than cyclopentenyl allyl ether (47) in benzene-d$\\sb6$ and 80% aqueous ethanol-d$\\sb6$, respectively. The significant substituent and solvent effects provide experimental evidence for a pronounced dipolar character of the transition state. Further ($>$45 fold) acceleration of the rearrangements from the combined influence of a 4-ethoxy group and a cyano or carbethoxy group at C-1 indicates a synergistic interaction of the donor and acceptor substituents.","The product stereoselectivity of the selenoxide fragmentation was examined by oxidation of 2-(phenylseleno)butyraldehyde diethyl acetal (56) which provided crotonaldehyde diethyl acetal (57) as an 87:13 (E: Z) mixture. Oxidation of various 2-(arylseleno)butyraldehyde vinyl ethyl acetals showed the product stereoselectivity (with respect to diastereomers produced as a result of the formation of contiguous chiral centers via rearrangement) of the overall process (8 $\\rightarrow$ 11) to vary between 88:12 (considered to be a stereoselective rearrangement) and 63:37 (ca. 34% stereoselectivity). The lack of consistent product stereoselectivity is believed to result from a high degree of C-4/O-3 bond cleavage in the transition state which reduces the free energy difference between the chair and boat transition states.","Made available in DSpace on 2014-12-15T23:19:01Z (GMT). No. of bitstreams: 1 8721744.pdf: 4567106 bytes, checksum: cd676a1dc8eb6a78bcc1618efbef4ce9 (MD5) Previous issue date: 1987","Embargo set by: Seth Robbins for item 70545 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","148 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1987."],"dc:identifier":["http://hdl.handle.net/2142/70379","(UMI)AAI8721744"],"dc:subject":["Chemistry, Organic"],"dc:title":["Synthesis and Claisen Rearrangement of Alpha-Ethoxyallyl Vinyl Ethers. Evidence for a Dipolar Transition State"],"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"}