Synthesis and One-Electron Oxidation Chemistry of Stable β,β-Dimesityl Enols with Heteroaryl Substituents

Abstract

Four novel stable enols (one characterized by X-ray crystal structure analysis) were synthesized and investigated under oxidative conditions to yield benzofurans. Depending on the donor qualities of the heteroaryl substituent the reaction following the one-electron oxidation could be stopped on the stage of the cyclohexadienyl cation whose lifetime was measured. Oxidation potentials were determined for the enols, the enolates and the α-carbonyl radicals. Oxidation of benzofurans yielded dimeric species or intramolecular cyclization products.