Electron transfer mechanism for periodic acid oxidation of aromatic substrates

Abstract

Oxidn. of phenolic ethers, e.g. $I (R = Me, R1 = H)$ with 1 equiv of $H_5IO$6 gave the iodinated product $I (R = Me, R1 = iodo)$. Use of 2 equiv of oxidant gave $I (R = CHO, R1 = iodo)$in which the side chain was oxidized. Oxidn. of binaphthyl II with either $H_5IO_6$ or ceric ammonium nitrate in MeOH gave the same cyclized product III. ESR signals were found for the $H_5IO_6$ oxidn. of 11 arom. substrates. The ESR data and addnl. chem. evidence suggest a radical cation mechanism for the oxidation