Electrochemical C-H oxygenation and alcohol dehydrogenation involving Fe-oxo species using water as the oxygen source

Abstract

High-valent iron-oxo complexes are key intermediates in C-H functionalization reactions. Herein, we report the generation of a (TAML)Fe-oxo species (TAML = tetraamido macrocyclic ligand) via electrochemical proton-coupled oxidation of the corresponding (TAML)FeIII-OH2 complex. Cyclic voltammetry (CV) and spectroelectrochemical studies are used to elucidate the relevant (TAML)Fe redox processes and determine the predominant (TAML)Fe species present in solution during bulk electrolysis. Evidence for iron(iv) and iron(v) species is presented, and these species are used in the electrochemical oxygenation of benzylic C-H bonds and dehydrogenation of alcohols to ketones.