Redox-active ligand promoted electrophile addition at cobalt

Abstract

The reactivity of an electron-rich cobalt complex bearing an o-phenylenediamide ligand with electrophilic CF₃⁺ and F⁺ sources is reported. These reactions lead to generation of a Co(III)–CF₃ or Co(III)–F complex, promoted by redox-active ligand-to-substrate two-electron transfer. The rate of trifluoromethyl addition at cobalt correlates with the potential difference between the cobalt complex and the CF₃⁺ source. We present initial demonstrations of radical trifluoromethylation and nucleophilic fluorination of organic substrates, setting the stage for the development of electrocatalytic pathways for these bond-forming reactions.