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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...

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Autores principales: Haines, Brandon E., Yu, Jin-Quan, Musaev, Djamaladdin G.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Royal Society of Chemistry 2017
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.
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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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