Electrochemical quinuclidine-mediated C-H activation: Intermediates and mechanism

The reaction mechanism of quinuclidine mediated C-H oxidation of unactivated C-H bonds has been elucidated. In-situ cathodically generated H2O2 was shown to diffuse to the anode where it is oxidized and participates in the ketonization reaction. Further oxidation of H2O2 to H2O, O2 and H+ leads to glassy carbon surface degradation. Oxidation of quinuclidine was shown be kinetic-diffusion control limited and shown to be irreversible at 0 and 1 M 1,1,1,3,3,3-hexafluoroisopropan-2-ol solutions, and quasi-reversible at 0.1 M. Competing side reactions of quinuclidine with hexafluroisopropanol and hydrogen peroxide were identified that lead to decreased reaction efficiency, which explains why quinuclidine needs to be used stoichiometrically.

Automated summary

The reaction mechanism of quinuclidine mediated C-H oxidation has been elucidated. It is shown that the oxidation is irreversible and is influenced by competing side reactions.