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The mechanism of directed Ni(ii)-catalyzed C–H iodination with molecular iodine
The density functional theory method is used to elucidate the elementary steps of Ni(ii)-catalyzed C(sp(2))–H iodination with I(2) and substrates bearing N,N′-bidentate directing centers, amide-oxazoline (AO) and 8-aminoquinoline (AQ). The relative stability of the lowest energy high- and low-spin e...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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Royal Society of Chemistry
2017
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5883947/ https://www.ncbi.nlm.nih.gov/pubmed/29675159 http://dx.doi.org/10.1039/c7sc04604a |
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author | Haines, Brandon E. Yu, Jin-Quan Musaev, Djamaladdin G. |
author_facet | Haines, Brandon E. Yu, Jin-Quan Musaev, Djamaladdin G. |
author_sort | Haines, Brandon E. |
collection | PubMed |
description | The density functional theory method is used to elucidate the elementary steps of Ni(ii)-catalyzed C(sp(2))–H iodination with I(2) and substrates bearing N,N′-bidentate directing centers, amide-oxazoline (AO) and 8-aminoquinoline (AQ). The relative stability of the lowest energy high- and low-spin electronic states of the catalyst and intermediates is found to be an important factor for all of the steps in the reaction. As a result, two-state reactivity for these systems is reported, where the reaction is initiated on the triplet surface and generates a high energy singlet nickelacycle. It is shown that the addition of Na(2)CO(3) base to the reaction mixture facilitates C–H activation. The presence of I(2) in the reaction provides the much needed driving force for the C–H activation and nickelacycle formation and ultimately reacts to form a new C–I bond through either a redox neutral electrophilic cleavage (EC) pathway or a one-electron reductive cleavage (REC) pathway. The previously proposed Ni(ii)/Ni(iv) and homolytic cleavage pathways are found to be higher in energy. The nature of the substrate is found to have a large impact on the relative stability of the lowest electronic states and on the stability of the nickelacycle resulting from C–H activation. |
format | Online Article Text |
id | pubmed-5883947 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2017 |
publisher | Royal Society of Chemistry |
record_format | MEDLINE/PubMed |
spelling | pubmed-58839472018-04-19 The mechanism of directed Ni(ii)-catalyzed C–H iodination with molecular iodine Haines, Brandon E. Yu, Jin-Quan Musaev, Djamaladdin G. Chem Sci Chemistry The density functional theory method is used to elucidate the elementary steps of Ni(ii)-catalyzed C(sp(2))–H iodination with I(2) and substrates bearing N,N′-bidentate directing centers, amide-oxazoline (AO) and 8-aminoquinoline (AQ). The relative stability of the lowest energy high- and low-spin electronic states of the catalyst and intermediates is found to be an important factor for all of the steps in the reaction. As a result, two-state reactivity for these systems is reported, where the reaction is initiated on the triplet surface and generates a high energy singlet nickelacycle. It is shown that the addition of Na(2)CO(3) base to the reaction mixture facilitates C–H activation. The presence of I(2) in the reaction provides the much needed driving force for the C–H activation and nickelacycle formation and ultimately reacts to form a new C–I bond through either a redox neutral electrophilic cleavage (EC) pathway or a one-electron reductive cleavage (REC) pathway. The previously proposed Ni(ii)/Ni(iv) and homolytic cleavage pathways are found to be higher in energy. The nature of the substrate is found to have a large impact on the relative stability of the lowest electronic states and on the stability of the nickelacycle resulting from C–H activation. Royal Society of Chemistry 2017-11-28 /pmc/articles/PMC5883947/ /pubmed/29675159 http://dx.doi.org/10.1039/c7sc04604a Text en This journal is © The Royal Society of Chemistry 2018 http://creativecommons.org/licenses/by/3.0/ This article is freely available. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence (CC BY 3.0) |
spellingShingle | Chemistry Haines, Brandon E. Yu, Jin-Quan Musaev, Djamaladdin G. The mechanism of directed Ni(ii)-catalyzed C–H iodination with molecular iodine |
title | The mechanism of directed Ni(ii)-catalyzed C–H iodination with molecular iodine
|
title_full | The mechanism of directed Ni(ii)-catalyzed C–H iodination with molecular iodine
|
title_fullStr | The mechanism of directed Ni(ii)-catalyzed C–H iodination with molecular iodine
|
title_full_unstemmed | The mechanism of directed Ni(ii)-catalyzed C–H iodination with molecular iodine
|
title_short | The mechanism of directed Ni(ii)-catalyzed C–H iodination with molecular iodine
|
title_sort | mechanism of directed ni(ii)-catalyzed c–h iodination with molecular iodine |
topic | Chemistry |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5883947/ https://www.ncbi.nlm.nih.gov/pubmed/29675159 http://dx.doi.org/10.1039/c7sc04604a |
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