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Photochemical ring expansion reactions: synthesis of tetrahydrofuran derivatives and mechanism studies
The reaction mechanism of oxygen and sulfur ylide mediated rearrangements is even today a matter of debate. In this report, we describe ring expansion reactions of oxetane and thietane heterocycles that allow probing the underlying reaction mechanism under metal-free, photochemical conditions. This...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Royal Society of Chemistry
2019
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6968735/ https://www.ncbi.nlm.nih.gov/pubmed/32015819 http://dx.doi.org/10.1039/c9sc04069b |
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author | Jana, Sripati Yang, Zhen Pei, Chao Xu, Xinfang Koenigs, Rene M. |
author_facet | Jana, Sripati Yang, Zhen Pei, Chao Xu, Xinfang Koenigs, Rene M. |
author_sort | Jana, Sripati |
collection | PubMed |
description | The reaction mechanism of oxygen and sulfur ylide mediated rearrangements is even today a matter of debate. In this report, we describe ring expansion reactions of oxetane and thietane heterocycles that allow probing the underlying reaction mechanism under metal-free, photochemical conditions. This ring expansion proves highly efficient and allows the synthesis of tetrahydrofuran and thiolane heterocycles under mild and operationally simple reaction conditions. These studies reveal marked differences in the stereoselectivity of the ring expansion of oxygen or sulfur ylides, which were further investigated computationally. DFT calculations show that carbenes react under ylide formation and that the corresponding ring expansion reactions proceed via a diradical pathway. The different bond lengths in free oxygen or sulfur ylide intermediates cause the distinctive stereochemical outcome. |
format | Online Article Text |
id | pubmed-6968735 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2019 |
publisher | Royal Society of Chemistry |
record_format | MEDLINE/PubMed |
spelling | pubmed-69687352020-02-03 Photochemical ring expansion reactions: synthesis of tetrahydrofuran derivatives and mechanism studies Jana, Sripati Yang, Zhen Pei, Chao Xu, Xinfang Koenigs, Rene M. Chem Sci Chemistry The reaction mechanism of oxygen and sulfur ylide mediated rearrangements is even today a matter of debate. In this report, we describe ring expansion reactions of oxetane and thietane heterocycles that allow probing the underlying reaction mechanism under metal-free, photochemical conditions. This ring expansion proves highly efficient and allows the synthesis of tetrahydrofuran and thiolane heterocycles under mild and operationally simple reaction conditions. These studies reveal marked differences in the stereoselectivity of the ring expansion of oxygen or sulfur ylides, which were further investigated computationally. DFT calculations show that carbenes react under ylide formation and that the corresponding ring expansion reactions proceed via a diradical pathway. The different bond lengths in free oxygen or sulfur ylide intermediates cause the distinctive stereochemical outcome. Royal Society of Chemistry 2019-09-06 /pmc/articles/PMC6968735/ /pubmed/32015819 http://dx.doi.org/10.1039/c9sc04069b Text en This journal is © The Royal Society of Chemistry 2019 http://creativecommons.org/licenses/by-nc/3.0/ This article is freely available. This article is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported Licence (CC BY-NC 3.0) |
spellingShingle | Chemistry Jana, Sripati Yang, Zhen Pei, Chao Xu, Xinfang Koenigs, Rene M. Photochemical ring expansion reactions: synthesis of tetrahydrofuran derivatives and mechanism studies |
title | Photochemical ring expansion reactions: synthesis of tetrahydrofuran derivatives and mechanism studies
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title_full | Photochemical ring expansion reactions: synthesis of tetrahydrofuran derivatives and mechanism studies
|
title_fullStr | Photochemical ring expansion reactions: synthesis of tetrahydrofuran derivatives and mechanism studies
|
title_full_unstemmed | Photochemical ring expansion reactions: synthesis of tetrahydrofuran derivatives and mechanism studies
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title_short | Photochemical ring expansion reactions: synthesis of tetrahydrofuran derivatives and mechanism studies
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title_sort | photochemical ring expansion reactions: synthesis of tetrahydrofuran derivatives and mechanism studies |
topic | Chemistry |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6968735/ https://www.ncbi.nlm.nih.gov/pubmed/32015819 http://dx.doi.org/10.1039/c9sc04069b |
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