Iodane-mediated and electrochemical oxidative transformations of2-methoxy- and 2-methylphenols

Abstract

A series of 2-methoxy and 2-methylphenols have been submitted to oxygenative oxidation reactions using (1) the λ3-iodane DIB, (2) a non-explosive and non-moisture sensitive version of the λ5-iodane IBX, named SIBX for Stabilized IBX, and (3) anodic oxidation with the aim of identifying the best reaction conditions for preparing orthoquinonoid cyclohexadienone synthons. Both the use of DIB and anodic oxidation appeared equally valuable for making orthoquinone dimethyl ketals, but the λ3- and λ5-iodane reagents are more appropriate to induce ortho-oxygenation of 2-methylphenols. In particular, SIBX emerged as a useful reagent for mediating ortho-hydroxylation into dimerizing orthoquinols, a tactic that can be applied to the synthesis of natural bis(monoterpenoids) such as aquaticol.