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