{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/70179"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/70179","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Synthetically Useful Dipole-Stabilized Carbanions From Thioesters and Thiocarbamates","abstract":"In an investigation of the formation of dipole-stabilized carbanions from thioesters, deprotonation of a tertiary center at the carbon adjacent to the sulfur of a thioester was found for the first time. Isopropyl, 2-octyl, and 4-tert-butylcyclohexyl 2,4,6-triisopropylthiobenzoates react with sec-butyllithium/TMEDA at -98(DEGREES)C to give synthetically useful (alpha)-lithio thioesters. These species react with electrophiles including primary alkyl halides and a variety of carbonyl compounds to give substituted thioesters. Study of the optically active 2-octyl thioester as well as the cis-4-tert-butylcyclohexyl thioester has shown that (alpha)-lithio thioesters are not configurationally stable. A general synthesis of trisubstituted thiiranes is provided by the action of sodium hydride on (beta)-hydroxy thioesters, which are obtained by reaction of the (alpha)-lithio thioesters with aldehydes.","abstract_html":"In an investigation of the formation of dipole-stabilized carbanions from thioesters, deprotonation of a tertiary center at the carbon adjacent to the sulfur of a thioester was found for the first time. Isopropyl, 2-octyl, and 4-tert-butylcyclohexyl 2,4,6-triisopropylthiobenzoates react with sec-butyllithium/TMEDA at -98(DEGREES)C to give synthetically useful (alpha)-lithio thioesters. These species react with electrophiles including primary alkyl halides and a variety of carbonyl compounds to give substituted thioesters. Study of the optically active 2-octyl thioester as well as the cis-4-tert-butylcyclohexyl thioester has shown that (alpha)-lithio thioesters are not configurationally stable. A general synthesis of trisubstituted thiiranes is provided by the action of sodium hydride on (beta)-hydroxy thioesters, which are obtained by reaction of the (alpha)-lithio thioesters with aldehydes.","abstract_has_math":false,"creators":["Becker, Peter Donald"],"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":"2014-12-15T23:17:33Z","date_published":"2014-12-15T23:17:33Z","updated_at":"2026-07-22T22:26:02Z","subjects":["Chemistry, Organic"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["(UMI)AAI8209543"],"render_values":[{"text":"(UMI)AAI8209543","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/70179","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Becker, Peter Donald"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2014-12-15T23:17:33Z","10000-01-01","1982"]},{"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/2142/70179","(UMI)AAI8209543"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["In an investigation of the formation of dipole-stabilized carbanions from thioesters, deprotonation of a tertiary center at the carbon adjacent to the sulfur of a thioester was found for the first time. Isopropyl, 2-octyl, and 4-tert-butylcyclohexyl 2,4,6-triisopropylthiobenzoates react with sec-butyllithium/TMEDA at -98(DEGREES)C to give synthetically useful (alpha)-lithio thioesters. These species react with electrophiles including primary alkyl halides and a variety of carbonyl compounds to give substituted thioesters. Study of the optically active 2-octyl thioester as well as the cis-4-tert-butylcyclohexyl thioester has shown that (alpha)-lithio thioesters are not configurationally stable. A general synthesis of trisubstituted thiiranes is provided by the action of sodium hydride on (beta)-hydroxy thioesters, which are obtained by reaction of the (alpha)-lithio thioesters with aldehydes.","Heptyl, neopentyl, diethylaminoethyl, methoxymethyl and allyl 2,4,6-triisopropylthiobenzoates form stable anions on reaction with sec-butyllithium/TMEDA which can be trapped with electrophiles. Ethoxyethyl and 2-methoxymethyl 2,4,6-triisopropylthiobenzoates undergo elimination to form vinyl thioesters which in turn are deprotonated adjacent to sulfur and react with electrophiles. The n-butoxymethyl 2,4,6-triisopropylthiobenzoate on the other hand decomposes to give lithium 2,4,6-triisopropylthiobenzoate.","The deprotonation of primary alkyl thiocarbamates adjacent to sulfur is also reported for the first time. Reaction of sec-butyllithium/TMEDA with S-ethyl and S-heptyl N,N-dimethylthiocarbamates gives the (alpha)-lithio species which react with electrophiles to give substituted thiocarbamates. These species are more readily hydrolyzed than the thioesters so they provide ready access to (alpha)-lithioalkylthiol synthons.","Made available in DSpace on 2014-12-15T23:17:33Z (GMT). No. of bitstreams: 1 8209543.pdf: 3077598 bytes, checksum: ce3f9a767f9f006626e71a78d2cd6697 (MD5) Previous issue date: 1982","Embargo set by: Seth Robbins for item 70345 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","103 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1982."]},{"key":"dc:title","label":"Title","values":["Synthetically Useful Dipole-Stabilized Carbanions From Thioesters and Thiocarbamates"]}]}],"canonical_facts":{"dc:creator":["Becker, Peter Donald"],"dc:date":["2014-12-15T23:17:33Z","10000-01-01","1982"],"dc:description":["In an investigation of the formation of dipole-stabilized carbanions from thioesters, deprotonation of a tertiary center at the carbon adjacent to the sulfur of a thioester was found for the first time. Isopropyl, 2-octyl, and 4-tert-butylcyclohexyl 2,4,6-triisopropylthiobenzoates react with sec-butyllithium/TMEDA at -98(DEGREES)C to give synthetically useful (alpha)-lithio thioesters. These species react with electrophiles including primary alkyl halides and a variety of carbonyl compounds to give substituted thioesters. Study of the optically active 2-octyl thioester as well as the cis-4-tert-butylcyclohexyl thioester has shown that (alpha)-lithio thioesters are not configurationally stable. A general synthesis of trisubstituted thiiranes is provided by the action of sodium hydride on (beta)-hydroxy thioesters, which are obtained by reaction of the (alpha)-lithio thioesters with aldehydes.","Heptyl, neopentyl, diethylaminoethyl, methoxymethyl and allyl 2,4,6-triisopropylthiobenzoates form stable anions on reaction with sec-butyllithium/TMEDA which can be trapped with electrophiles. Ethoxyethyl and 2-methoxymethyl 2,4,6-triisopropylthiobenzoates undergo elimination to form vinyl thioesters which in turn are deprotonated adjacent to sulfur and react with electrophiles. The n-butoxymethyl 2,4,6-triisopropylthiobenzoate on the other hand decomposes to give lithium 2,4,6-triisopropylthiobenzoate.","The deprotonation of primary alkyl thiocarbamates adjacent to sulfur is also reported for the first time. Reaction of sec-butyllithium/TMEDA with S-ethyl and S-heptyl N,N-dimethylthiocarbamates gives the (alpha)-lithio species which react with electrophiles to give substituted thiocarbamates. These species are more readily hydrolyzed than the thioesters so they provide ready access to (alpha)-lithioalkylthiol synthons.","Made available in DSpace on 2014-12-15T23:17:33Z (GMT). No. of bitstreams: 1 8209543.pdf: 3077598 bytes, checksum: ce3f9a767f9f006626e71a78d2cd6697 (MD5) Previous issue date: 1982","Embargo set by: Seth Robbins for item 70345 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","103 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1982."],"dc:identifier":["http://hdl.handle.net/2142/70179","(UMI)AAI8209543"],"dc:subject":["Chemistry, Organic"],"dc:title":["Synthetically Useful Dipole-Stabilized Carbanions From Thioesters and Thiocarbamates"],"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"}