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Carbene-catalysed reductive coupling of nitrobenzyl bromides and activated ketones or imines via single-electron-transfer process

Benzyl bromides and related molecules are among the most common substrates in organic synthesis. They are typically used as electrophiles in nucleophilic substitution reactions. These molecules can also be activated via single-electron-transfer (SET) process for radical reactions. Representative rec...

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Autores principales: Li, Bao-Sheng, Wang, Yuhuang, Proctor, Rupert S. J., Zhang, Yuexia, Webster, Richard D., Yang, Song, Song, Baoan, Chi, Yonggui Robin
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5052654/
https://www.ncbi.nlm.nih.gov/pubmed/27671606
http://dx.doi.org/10.1038/ncomms12933
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author Li, Bao-Sheng
Wang, Yuhuang
Proctor, Rupert S. J.
Zhang, Yuexia
Webster, Richard D.
Yang, Song
Song, Baoan
Chi, Yonggui Robin
author_facet Li, Bao-Sheng
Wang, Yuhuang
Proctor, Rupert S. J.
Zhang, Yuexia
Webster, Richard D.
Yang, Song
Song, Baoan
Chi, Yonggui Robin
author_sort Li, Bao-Sheng
collection PubMed
description Benzyl bromides and related molecules are among the most common substrates in organic synthesis. They are typically used as electrophiles in nucleophilic substitution reactions. These molecules can also be activated via single-electron-transfer (SET) process for radical reactions. Representative recent progress includes α-carbon benzylation of ketones and aldehydes via photoredox catalysis. Here we disclose the generation of (nitro)benzyl radicals via N-heterocyclic carbene (NHC) catalysis under reductive conditions. The radical intermediates generated via NHC catalysis undergo formal 1,2-addition with ketones to eventually afford tertiary alcohol products. The overall process constitutes a formal polarity-inversion of benzyl bromide, allowing a direct coupling of two initially electrophilic carbons. Our study provides a new carbene-catalysed reaction mode that should enable unconventional transformation of (nitro)benzyl bromides under mild organocatalytic conditions.
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spelling pubmed-50526542016-10-21 Carbene-catalysed reductive coupling of nitrobenzyl bromides and activated ketones or imines via single-electron-transfer process Li, Bao-Sheng Wang, Yuhuang Proctor, Rupert S. J. Zhang, Yuexia Webster, Richard D. Yang, Song Song, Baoan Chi, Yonggui Robin Nat Commun Article Benzyl bromides and related molecules are among the most common substrates in organic synthesis. They are typically used as electrophiles in nucleophilic substitution reactions. These molecules can also be activated via single-electron-transfer (SET) process for radical reactions. Representative recent progress includes α-carbon benzylation of ketones and aldehydes via photoredox catalysis. Here we disclose the generation of (nitro)benzyl radicals via N-heterocyclic carbene (NHC) catalysis under reductive conditions. The radical intermediates generated via NHC catalysis undergo formal 1,2-addition with ketones to eventually afford tertiary alcohol products. The overall process constitutes a formal polarity-inversion of benzyl bromide, allowing a direct coupling of two initially electrophilic carbons. Our study provides a new carbene-catalysed reaction mode that should enable unconventional transformation of (nitro)benzyl bromides under mild organocatalytic conditions. Nature Publishing Group 2016-09-27 /pmc/articles/PMC5052654/ /pubmed/27671606 http://dx.doi.org/10.1038/ncomms12933 Text en Copyright © 2016, The Author(s) http://creativecommons.org/licenses/by/4.0/ This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/
spellingShingle Article
Li, Bao-Sheng
Wang, Yuhuang
Proctor, Rupert S. J.
Zhang, Yuexia
Webster, Richard D.
Yang, Song
Song, Baoan
Chi, Yonggui Robin
Carbene-catalysed reductive coupling of nitrobenzyl bromides and activated ketones or imines via single-electron-transfer process
title Carbene-catalysed reductive coupling of nitrobenzyl bromides and activated ketones or imines via single-electron-transfer process
title_full Carbene-catalysed reductive coupling of nitrobenzyl bromides and activated ketones or imines via single-electron-transfer process
title_fullStr Carbene-catalysed reductive coupling of nitrobenzyl bromides and activated ketones or imines via single-electron-transfer process
title_full_unstemmed Carbene-catalysed reductive coupling of nitrobenzyl bromides and activated ketones or imines via single-electron-transfer process
title_short Carbene-catalysed reductive coupling of nitrobenzyl bromides and activated ketones or imines via single-electron-transfer process
title_sort carbene-catalysed reductive coupling of nitrobenzyl bromides and activated ketones or imines via single-electron-transfer process
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5052654/
https://www.ncbi.nlm.nih.gov/pubmed/27671606
http://dx.doi.org/10.1038/ncomms12933
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