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Distal Ruthenaelectro-Catalyzed meta-C-H Bromination with Aqueous HBr.

ABSTRACT: While electrochemical ortho-selective C-H activations are well established, distal C-H activations continue to be underdeveloped. In contrast, we herein describe the electrochemical meta-C-H functionalization. The remote C-H bromination was accomplished in an undivided cell by RuCl₃ ⋅3 H₂ O with aqueous HBr. The electrohalogenation proceeded under exogenous ligand- and electrolyte-free conditions. Notably, pyrazolylarenes were meta-selectively brominated at the benzenoid moiety, rather than on the electron-rich pyrazole ring for the first time. Mechanistic studies were suggestive of an initial ruthenacycle formation, and a subsequent ligand-to-ligand hydrogen transfer (LLHT) process to liberate the brominated product.

SUBMITTER: Wang Y

PROVIDER: S-EPMC9310730 | biostudies-literature | 2022 May

REPOSITORIES: biostudies-literature

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Distal Ruthenaelectro-Catalyzed meta-C-H Bromination with Aqueous HBr.

Wang Yulei Y Simon Hendrik H Chen Xinran X Lin Zhipeng Z Chen Shan S Ackermann Lutz L

Angewandte Chemie (International ed. in English) 20220316 20

While electrochemical ortho-selective C-H activations are well established, distal C-H activations continue to be underdeveloped. In contrast, we herein describe the electrochemical meta-C-H functionalization. The remote C-H bromination was accomplished in an undivided cell by RuCl3 ⋅3 H2 O with aqueous HBr. The electrohalogenation proceeded under exogenous ligand- and electrolyte-free conditions. Notably, pyrazolylarenes were meta-selectively brominated at the benzenoid mo ...[more]

PMID: 35172030

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