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SmI(2)-Catalyzed Intermolecular Coupling of Cyclopropyl Ketones and Alkynes: A Link between Ketone Conformation and Reactivity
[Image: see text] The archetypal single electron transfer reductant, samarium(II) diiodide (SmI(2), Kagan’s reagent), remains one of the most important reducing agents and mediators of radical chemistry after four decades of widespread use in synthesis. While the chemistry of SmI(2) is very often un...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Chemical
Society
2021
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8028054/ https://www.ncbi.nlm.nih.gov/pubmed/33629852 http://dx.doi.org/10.1021/jacs.1c01356 |
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author | Agasti, Soumitra Beattie, Nicholas A. McDouall, Joseph J. W. Procter, David J. |
author_facet | Agasti, Soumitra Beattie, Nicholas A. McDouall, Joseph J. W. Procter, David J. |
author_sort | Agasti, Soumitra |
collection | PubMed |
description | [Image: see text] The archetypal single electron transfer reductant, samarium(II) diiodide (SmI(2), Kagan’s reagent), remains one of the most important reducing agents and mediators of radical chemistry after four decades of widespread use in synthesis. While the chemistry of SmI(2) is very often unique, and thus the reagent is indispensable, it is almost invariably used in superstoichiometric amounts, thus raising issues of cost and waste. Of the few reports of the use of catalytic SmI(2), all require the use of superstoichiometric amounts of a metal coreductant to regenerate Sm(II). Here, we describe a SmI(2)-catalyzed intermolecular radical coupling of aryl cyclopropyl ketones and alkynes. The process shows broad substrate scope and delivers a library of decorated cyclopentenes with loadings of SmI(2) as low as 15 mol %. The radical relay strategy negates the need for a superstoichiometric coreductant and additives to regenerate SmI(2). Crucially, our study uncovers an intriguing link between ketone conformation and efficient cross-coupling and thus provides an insight into the mechanism of radical relays involving SmI(2). The study lays further groundwork for the future use of the classical reagent SmI(2) in contemporary radical catalysis. |
format | Online Article Text |
id | pubmed-8028054 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2021 |
publisher | American Chemical
Society |
record_format | MEDLINE/PubMed |
spelling | pubmed-80280542021-04-08 SmI(2)-Catalyzed Intermolecular Coupling of Cyclopropyl Ketones and Alkynes: A Link between Ketone Conformation and Reactivity Agasti, Soumitra Beattie, Nicholas A. McDouall, Joseph J. W. Procter, David J. J Am Chem Soc [Image: see text] The archetypal single electron transfer reductant, samarium(II) diiodide (SmI(2), Kagan’s reagent), remains one of the most important reducing agents and mediators of radical chemistry after four decades of widespread use in synthesis. While the chemistry of SmI(2) is very often unique, and thus the reagent is indispensable, it is almost invariably used in superstoichiometric amounts, thus raising issues of cost and waste. Of the few reports of the use of catalytic SmI(2), all require the use of superstoichiometric amounts of a metal coreductant to regenerate Sm(II). Here, we describe a SmI(2)-catalyzed intermolecular radical coupling of aryl cyclopropyl ketones and alkynes. The process shows broad substrate scope and delivers a library of decorated cyclopentenes with loadings of SmI(2) as low as 15 mol %. The radical relay strategy negates the need for a superstoichiometric coreductant and additives to regenerate SmI(2). Crucially, our study uncovers an intriguing link between ketone conformation and efficient cross-coupling and thus provides an insight into the mechanism of radical relays involving SmI(2). The study lays further groundwork for the future use of the classical reagent SmI(2) in contemporary radical catalysis. American Chemical Society 2021-02-25 2021-03-10 /pmc/articles/PMC8028054/ /pubmed/33629852 http://dx.doi.org/10.1021/jacs.1c01356 Text en © 2021 The Authors. Published by American Chemical Society Permits the broadest form of re-use including for commercial purposes, provided that author attribution and integrity are maintained (https://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Agasti, Soumitra Beattie, Nicholas A. McDouall, Joseph J. W. Procter, David J. SmI(2)-Catalyzed Intermolecular Coupling of Cyclopropyl Ketones and Alkynes: A Link between Ketone Conformation and Reactivity |
title | SmI(2)-Catalyzed Intermolecular Coupling
of Cyclopropyl Ketones and Alkynes: A Link between Ketone Conformation
and Reactivity |
title_full | SmI(2)-Catalyzed Intermolecular Coupling
of Cyclopropyl Ketones and Alkynes: A Link between Ketone Conformation
and Reactivity |
title_fullStr | SmI(2)-Catalyzed Intermolecular Coupling
of Cyclopropyl Ketones and Alkynes: A Link between Ketone Conformation
and Reactivity |
title_full_unstemmed | SmI(2)-Catalyzed Intermolecular Coupling
of Cyclopropyl Ketones and Alkynes: A Link between Ketone Conformation
and Reactivity |
title_short | SmI(2)-Catalyzed Intermolecular Coupling
of Cyclopropyl Ketones and Alkynes: A Link between Ketone Conformation
and Reactivity |
title_sort | smi(2)-catalyzed intermolecular coupling
of cyclopropyl ketones and alkynes: a link between ketone conformation
and reactivity |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8028054/ https://www.ncbi.nlm.nih.gov/pubmed/33629852 http://dx.doi.org/10.1021/jacs.1c01356 |
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