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Fates of imine intermediates in radical cyclizations of N-sulfonylindoles and ene-sulfonamides

Two new fates of imine intermediates formed on radical cyclizations of ene-sulfonamides have been identified, reduction and hydration/fragmentation. Tin hydride-mediated cyclizations of 2-halo-N-(3-methyl-N-sulfonylindole)anilines provide spiro[indoline-3,3'-indolones] or spiro-3,3'-biindo...

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Autores principales: Zhang, Hanmo, Hay, E Ben, Geib, Stephen J, Curran, Dennis P
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Beilstein-Institut 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4660904/
https://www.ncbi.nlm.nih.gov/pubmed/26664585
http://dx.doi.org/10.3762/bjoc.11.181
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author Zhang, Hanmo
Hay, E Ben
Geib, Stephen J
Curran, Dennis P
author_facet Zhang, Hanmo
Hay, E Ben
Geib, Stephen J
Curran, Dennis P
author_sort Zhang, Hanmo
collection PubMed
description Two new fates of imine intermediates formed on radical cyclizations of ene-sulfonamides have been identified, reduction and hydration/fragmentation. Tin hydride-mediated cyclizations of 2-halo-N-(3-methyl-N-sulfonylindole)anilines provide spiro[indoline-3,3'-indolones] or spiro-3,3'-biindolines (derived from imine reduction), depending on the indole C2 substituent. Cyclizations of 2-haloanilide derivatives of 3-carboxy-N-sulfonyl-2,3-dihydropyrroles also presumably form spiro-imines as primary products. However, the lactam carbonyl group facilitates the ring-opening of these cyclic imines by a new pathway of hydration and retro-Claisen-type reaction, providing rearranged 2-(2'-formamidoethyl)oxindoles.
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spelling pubmed-46609042015-12-09 Fates of imine intermediates in radical cyclizations of N-sulfonylindoles and ene-sulfonamides Zhang, Hanmo Hay, E Ben Geib, Stephen J Curran, Dennis P Beilstein J Org Chem Full Research Paper Two new fates of imine intermediates formed on radical cyclizations of ene-sulfonamides have been identified, reduction and hydration/fragmentation. Tin hydride-mediated cyclizations of 2-halo-N-(3-methyl-N-sulfonylindole)anilines provide spiro[indoline-3,3'-indolones] or spiro-3,3'-biindolines (derived from imine reduction), depending on the indole C2 substituent. Cyclizations of 2-haloanilide derivatives of 3-carboxy-N-sulfonyl-2,3-dihydropyrroles also presumably form spiro-imines as primary products. However, the lactam carbonyl group facilitates the ring-opening of these cyclic imines by a new pathway of hydration and retro-Claisen-type reaction, providing rearranged 2-(2'-formamidoethyl)oxindoles. Beilstein-Institut 2015-09-17 /pmc/articles/PMC4660904/ /pubmed/26664585 http://dx.doi.org/10.3762/bjoc.11.181 Text en Copyright © 2015, Zhang et al. https://creativecommons.org/licenses/by/2.0https://www.beilstein-journals.org/bjoc/termsThis is an Open Access article under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The license is subject to the Beilstein Journal of Organic Chemistry terms and conditions: (https://www.beilstein-journals.org/bjoc/terms)
spellingShingle Full Research Paper
Zhang, Hanmo
Hay, E Ben
Geib, Stephen J
Curran, Dennis P
Fates of imine intermediates in radical cyclizations of N-sulfonylindoles and ene-sulfonamides
title Fates of imine intermediates in radical cyclizations of N-sulfonylindoles and ene-sulfonamides
title_full Fates of imine intermediates in radical cyclizations of N-sulfonylindoles and ene-sulfonamides
title_fullStr Fates of imine intermediates in radical cyclizations of N-sulfonylindoles and ene-sulfonamides
title_full_unstemmed Fates of imine intermediates in radical cyclizations of N-sulfonylindoles and ene-sulfonamides
title_short Fates of imine intermediates in radical cyclizations of N-sulfonylindoles and ene-sulfonamides
title_sort fates of imine intermediates in radical cyclizations of n-sulfonylindoles and ene-sulfonamides
topic Full Research Paper
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4660904/
https://www.ncbi.nlm.nih.gov/pubmed/26664585
http://dx.doi.org/10.3762/bjoc.11.181
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