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Radical chain monoalkylation of pyridines
The monoalkylation of N-methoxypyridinium salts with alkyl radicals generated from alkenes (via hydroboration with catecholborane), alkyl iodides (via iodine atom transfer) and xanthates is reported. The reaction proceeds under neutral conditions since no acid is needed to activate the heterocycle a...
Autores principales: | , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
The Royal Society of Chemistry
2021
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8635225/ https://www.ncbi.nlm.nih.gov/pubmed/34976357 http://dx.doi.org/10.1039/d1sc02748d |
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author | Rieder, Samuel Meléndez, Camilo Dénès, Fabrice Jangra, Harish Mulliri, Kleni Zipse, Hendrik Renaud, Philippe |
author_facet | Rieder, Samuel Meléndez, Camilo Dénès, Fabrice Jangra, Harish Mulliri, Kleni Zipse, Hendrik Renaud, Philippe |
author_sort | Rieder, Samuel |
collection | PubMed |
description | The monoalkylation of N-methoxypyridinium salts with alkyl radicals generated from alkenes (via hydroboration with catecholborane), alkyl iodides (via iodine atom transfer) and xanthates is reported. The reaction proceeds under neutral conditions since no acid is needed to activate the heterocycle and no external oxidant is required. A rate constant for the addition of a primary radical to N-methoxylepidinium >10(7) M(−1) s(−1) was experimentally determined. This rate constant is more than one order of magnitude larger than the one measured for the addition of primary alkyl radicals to protonated lepidine demonstrating the remarkable reactivity of methoxypyridinium salts towards radicals. The reaction has been used for the preparation of unique pyridinylated terpenoids and was extended to a three-component carbopyridinylation of electron-rich alkenes including enol esters, enol ethers and enamides. |
format | Online Article Text |
id | pubmed-8635225 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2021 |
publisher | The Royal Society of Chemistry |
record_format | MEDLINE/PubMed |
spelling | pubmed-86352252021-12-30 Radical chain monoalkylation of pyridines Rieder, Samuel Meléndez, Camilo Dénès, Fabrice Jangra, Harish Mulliri, Kleni Zipse, Hendrik Renaud, Philippe Chem Sci Chemistry The monoalkylation of N-methoxypyridinium salts with alkyl radicals generated from alkenes (via hydroboration with catecholborane), alkyl iodides (via iodine atom transfer) and xanthates is reported. The reaction proceeds under neutral conditions since no acid is needed to activate the heterocycle and no external oxidant is required. A rate constant for the addition of a primary radical to N-methoxylepidinium >10(7) M(−1) s(−1) was experimentally determined. This rate constant is more than one order of magnitude larger than the one measured for the addition of primary alkyl radicals to protonated lepidine demonstrating the remarkable reactivity of methoxypyridinium salts towards radicals. The reaction has been used for the preparation of unique pyridinylated terpenoids and was extended to a three-component carbopyridinylation of electron-rich alkenes including enol esters, enol ethers and enamides. The Royal Society of Chemistry 2021-11-03 /pmc/articles/PMC8635225/ /pubmed/34976357 http://dx.doi.org/10.1039/d1sc02748d Text en This journal is © The Royal Society of Chemistry https://creativecommons.org/licenses/by/3.0/ |
spellingShingle | Chemistry Rieder, Samuel Meléndez, Camilo Dénès, Fabrice Jangra, Harish Mulliri, Kleni Zipse, Hendrik Renaud, Philippe Radical chain monoalkylation of pyridines |
title | Radical chain monoalkylation of pyridines |
title_full | Radical chain monoalkylation of pyridines |
title_fullStr | Radical chain monoalkylation of pyridines |
title_full_unstemmed | Radical chain monoalkylation of pyridines |
title_short | Radical chain monoalkylation of pyridines |
title_sort | radical chain monoalkylation of pyridines |
topic | Chemistry |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8635225/ https://www.ncbi.nlm.nih.gov/pubmed/34976357 http://dx.doi.org/10.1039/d1sc02748d |
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