Learning From Vitamin B 12 -Mediated Reactions

Cobalt(III)−Carbon-Assisted Catalytic C−H Difluoroacylation of (Hetero)Arenes through Controlled-Potential Electrolysis

Md Jakir Hossain, Toshikazu Ono, Yoshio Yano, Yoshio Hisaeda

Research output: Contribution to journalArticle

Abstract

The synthesis of difluoromethylated (CF 2 R) (R=H, alkyl/aryl, CO 2 R, etc.) compounds has received considerable attention in recent years. In this study, the cobalt(III)−carbon-mediated catalytic C−H difluoroacylation of unactivated arenes and heteroarenes using BrCF 2 CO 2 Et is reported. This catalytic cycle is based on a valence change of the cobalt catalyst, a naturally derived vitamin B 12 derivative, driven by controlled-potential electrolysis at −0.8 V vs. Ag/AgCl under visible-light irradiation in dimethyl sulfoxide. A broad substrate scope is demonstrated, and two compounds were characterized according to their X-ray crystal structures. Mechanistic studies showed that the reaction proceeds through a radical pathway mediated by homolytic cleavage of the cobalt(III)–carbon bond. A turnover number of more than 100 was observed, owing to the inherent stability of the vitamin B 12 framework. This naturally derived catalytic system has potential applications in medicinal chemistry and materials science.

Original languageEnglish
JournalChemElectroChem
DOIs
Publication statusPublished - Jan 1 2019

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Vitamins
Vitamin B 12
Cobalt
Electrolysis
Carbon
Carbon Monoxide
Dimethyl sulfoxide
Materials science
Dimethyl Sulfoxide
Crystal structure
Irradiation
Derivatives
X rays
Catalysts
Substrates

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Electrochemistry

Cite this

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title = "Learning From Vitamin B 12 -Mediated Reactions: Cobalt(III)−Carbon-Assisted Catalytic C−H Difluoroacylation of (Hetero)Arenes through Controlled-Potential Electrolysis",
abstract = "The synthesis of difluoromethylated (CF 2 R) (R=H, alkyl/aryl, CO 2 R, etc.) compounds has received considerable attention in recent years. In this study, the cobalt(III)−carbon-mediated catalytic C−H difluoroacylation of unactivated arenes and heteroarenes using BrCF 2 CO 2 Et is reported. This catalytic cycle is based on a valence change of the cobalt catalyst, a naturally derived vitamin B 12 derivative, driven by controlled-potential electrolysis at −0.8 V vs. Ag/AgCl under visible-light irradiation in dimethyl sulfoxide. A broad substrate scope is demonstrated, and two compounds were characterized according to their X-ray crystal structures. Mechanistic studies showed that the reaction proceeds through a radical pathway mediated by homolytic cleavage of the cobalt(III)–carbon bond. A turnover number of more than 100 was observed, owing to the inherent stability of the vitamin B 12 framework. This naturally derived catalytic system has potential applications in medicinal chemistry and materials science.",
author = "Hossain, {Md Jakir} and Toshikazu Ono and Yoshio Yano and Yoshio Hisaeda",
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T2 - Cobalt(III)−Carbon-Assisted Catalytic C−H Difluoroacylation of (Hetero)Arenes through Controlled-Potential Electrolysis

AU - Hossain, Md Jakir

AU - Ono, Toshikazu

AU - Yano, Yoshio

AU - Hisaeda, Yoshio

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N2 - The synthesis of difluoromethylated (CF 2 R) (R=H, alkyl/aryl, CO 2 R, etc.) compounds has received considerable attention in recent years. In this study, the cobalt(III)−carbon-mediated catalytic C−H difluoroacylation of unactivated arenes and heteroarenes using BrCF 2 CO 2 Et is reported. This catalytic cycle is based on a valence change of the cobalt catalyst, a naturally derived vitamin B 12 derivative, driven by controlled-potential electrolysis at −0.8 V vs. Ag/AgCl under visible-light irradiation in dimethyl sulfoxide. A broad substrate scope is demonstrated, and two compounds were characterized according to their X-ray crystal structures. Mechanistic studies showed that the reaction proceeds through a radical pathway mediated by homolytic cleavage of the cobalt(III)–carbon bond. A turnover number of more than 100 was observed, owing to the inherent stability of the vitamin B 12 framework. This naturally derived catalytic system has potential applications in medicinal chemistry and materials science.

AB - The synthesis of difluoromethylated (CF 2 R) (R=H, alkyl/aryl, CO 2 R, etc.) compounds has received considerable attention in recent years. In this study, the cobalt(III)−carbon-mediated catalytic C−H difluoroacylation of unactivated arenes and heteroarenes using BrCF 2 CO 2 Et is reported. This catalytic cycle is based on a valence change of the cobalt catalyst, a naturally derived vitamin B 12 derivative, driven by controlled-potential electrolysis at −0.8 V vs. Ag/AgCl under visible-light irradiation in dimethyl sulfoxide. A broad substrate scope is demonstrated, and two compounds were characterized according to their X-ray crystal structures. Mechanistic studies showed that the reaction proceeds through a radical pathway mediated by homolytic cleavage of the cobalt(III)–carbon bond. A turnover number of more than 100 was observed, owing to the inherent stability of the vitamin B 12 framework. This naturally derived catalytic system has potential applications in medicinal chemistry and materials science.

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