Lewis Acid Catalysis in the Oxidative Cycloaddition of Thiophenes
Autor(a) principal: | |
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Data de Publicação: | 1997 |
Outros Autores: | , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
Texto Completo: | http://hdl.handle.net/10316/10321 https://doi.org/10.1021/jo961985z |
Resumo: | Thiophenes 1 were treated with m-chloroperbenzoic acid (m-CPBA) under BF3·Et2O catalysis to afford thiophene S-monoxides. These could be reacted in situ as intermediary species with a number of dienophiles to provide arenes (with alkynes as dienophiles) or 7-thiabicyclo[2.2.1]hept-2-ene 7-oxides (with alkenes as dienophiles). It was also possible to isolate thiophene S-monoxides in solution and to cycloadd them in a second step. In either way it could be shown that the use of BF3·Et2O enhances the yields of the oxidative cycloaddition of thiophenes considerably. Moreover a greater variety of dienophiles (29a, 29b, 29c) could be reacted with thiophenes than in the case of the noncatalyzed reaction. All cycloadditions catalyzed by BF3·Et2O give only a single diastereoisomer as cycloadduct. The reactions show a high π-facial selectivity, a fact that can be explained by the Cieplak-effect. Without added dienophiles, 2-methylthiophene (1e) gave a single dimer (36) of 2-methylthiophene S-monoxide, whereas 2,5-dimethylthiophene (1a) gave three dimers (32a−c). In the case of tetrasubstituted thiophenes, thiophene S-monoxides (e.g., 31b and 31c) could be isolated in substance. |
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Lewis Acid Catalysis in the Oxidative Cycloaddition of ThiophenesThiophenes 1 were treated with m-chloroperbenzoic acid (m-CPBA) under BF3·Et2O catalysis to afford thiophene S-monoxides. These could be reacted in situ as intermediary species with a number of dienophiles to provide arenes (with alkynes as dienophiles) or 7-thiabicyclo[2.2.1]hept-2-ene 7-oxides (with alkenes as dienophiles). It was also possible to isolate thiophene S-monoxides in solution and to cycloadd them in a second step. In either way it could be shown that the use of BF3·Et2O enhances the yields of the oxidative cycloaddition of thiophenes considerably. Moreover a greater variety of dienophiles (29a, 29b, 29c) could be reacted with thiophenes than in the case of the noncatalyzed reaction. All cycloadditions catalyzed by BF3·Et2O give only a single diastereoisomer as cycloadduct. The reactions show a high π-facial selectivity, a fact that can be explained by the Cieplak-effect. Without added dienophiles, 2-methylthiophene (1e) gave a single dimer (36) of 2-methylthiophene S-monoxide, whereas 2,5-dimethylthiophene (1a) gave three dimers (32a−c). In the case of tetrasubstituted thiophenes, thiophene S-monoxides (e.g., 31b and 31c) could be isolated in substance.American Chemical Society1997-11-14info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articlehttp://hdl.handle.net/10316/10321http://hdl.handle.net/10316/10321https://doi.org/10.1021/jo961985zengThe Journal of Organic Chemistry. 62:23 (1997) 7926-79360022-3263Li, YuanqiangThiemann, ThiesSawada, TsuyoshiMataka, ShuntaroTashiro, Masashiinfo:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2020-05-25T01:33:10Zoai:estudogeral.uc.pt:10316/10321Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-19T20:47:16.684786Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse |
dc.title.none.fl_str_mv |
Lewis Acid Catalysis in the Oxidative Cycloaddition of Thiophenes |
title |
Lewis Acid Catalysis in the Oxidative Cycloaddition of Thiophenes |
spellingShingle |
Lewis Acid Catalysis in the Oxidative Cycloaddition of Thiophenes Li, Yuanqiang |
title_short |
Lewis Acid Catalysis in the Oxidative Cycloaddition of Thiophenes |
title_full |
Lewis Acid Catalysis in the Oxidative Cycloaddition of Thiophenes |
title_fullStr |
Lewis Acid Catalysis in the Oxidative Cycloaddition of Thiophenes |
title_full_unstemmed |
Lewis Acid Catalysis in the Oxidative Cycloaddition of Thiophenes |
title_sort |
Lewis Acid Catalysis in the Oxidative Cycloaddition of Thiophenes |
author |
Li, Yuanqiang |
author_facet |
Li, Yuanqiang Thiemann, Thies Sawada, Tsuyoshi Mataka, Shuntaro Tashiro, Masashi |
author_role |
author |
author2 |
Thiemann, Thies Sawada, Tsuyoshi Mataka, Shuntaro Tashiro, Masashi |
author2_role |
author author author author |
dc.contributor.author.fl_str_mv |
Li, Yuanqiang Thiemann, Thies Sawada, Tsuyoshi Mataka, Shuntaro Tashiro, Masashi |
description |
Thiophenes 1 were treated with m-chloroperbenzoic acid (m-CPBA) under BF3·Et2O catalysis to afford thiophene S-monoxides. These could be reacted in situ as intermediary species with a number of dienophiles to provide arenes (with alkynes as dienophiles) or 7-thiabicyclo[2.2.1]hept-2-ene 7-oxides (with alkenes as dienophiles). It was also possible to isolate thiophene S-monoxides in solution and to cycloadd them in a second step. In either way it could be shown that the use of BF3·Et2O enhances the yields of the oxidative cycloaddition of thiophenes considerably. Moreover a greater variety of dienophiles (29a, 29b, 29c) could be reacted with thiophenes than in the case of the noncatalyzed reaction. All cycloadditions catalyzed by BF3·Et2O give only a single diastereoisomer as cycloadduct. The reactions show a high π-facial selectivity, a fact that can be explained by the Cieplak-effect. Without added dienophiles, 2-methylthiophene (1e) gave a single dimer (36) of 2-methylthiophene S-monoxide, whereas 2,5-dimethylthiophene (1a) gave three dimers (32a−c). In the case of tetrasubstituted thiophenes, thiophene S-monoxides (e.g., 31b and 31c) could be isolated in substance. |
publishDate |
1997 |
dc.date.none.fl_str_mv |
1997-11-14 |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://hdl.handle.net/10316/10321 http://hdl.handle.net/10316/10321 https://doi.org/10.1021/jo961985z |
url |
http://hdl.handle.net/10316/10321 https://doi.org/10.1021/jo961985z |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
The Journal of Organic Chemistry. 62:23 (1997) 7926-7936 0022-3263 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.publisher.none.fl_str_mv |
American Chemical Society |
publisher.none.fl_str_mv |
American Chemical Society |
dc.source.none.fl_str_mv |
reponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação instacron:RCAAP |
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Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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RCAAP |
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RCAAP |
reponame_str |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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1799133750062219264 |