Anodic oxidation of organophosphorus compounds. Part 2. Formation of dialkyl arylphosphonates via arylation of trialkyl phosphites

Abstract

Anodic oxidation of trialkyl phosphites (1) has been investigated by cyclic voltammetry and controlled-potential electrolysis at a glassy-carbon electrode in acetonitrile. On electrolysis of (1) in the presence of an excess of various substituted benzenes, formation of trialkoxyarylphosphonium ion was recognized. The reaction sequence is suggested to be one-electron oxidation of (1), electrophilic attack of the resulting cation radical on the aromatic hydrocarbon, and a further one-electron transfer and loss of a proton. The phosphonium ion was converted, into the corresponding dialkyl arylphosphonate on treatment with sodium iodide.