IBS-Catalyzed Regioselective Oxidation of Phenols to 1,2-Quinones with Oxone<sup>®</sup>

Abstract

We have developed the first example of hypervalent iodine(V)-catalyzed regioselective oxidation of phenols to <em>o</em>-quinones. Various phenols could be oxidized to the corresponding <em>o</em>-quinones in good to excellent yields using catalytic amounts of sodium salts of 2-iodobenzenesulfonic acids (<em>pre</em>-IBSes) and stoichiometric amounts of Oxone^® as a co-oxidant under mild conditions. The reaction rate of IBS-catalyzed oxidation under nonaqueous conditions was further accelerated in the presence of an inorganic base such as potassium carbonate (K₂CO₃), a phase transfer catalyst such as tetrabutylammonium hydrogen sulfate (<em>n</em>Bu₄NHSO₄), and a dehydrating agent such as anhydrous sodium sulfate (Na₂SO₄).

Keywords

• xidation
• phenol
• &lt;em&gt;o&lt;/em&gt;-quinone
• 2-iodoxybenzenesulfonic acid (IBS)
• Oxone&lt;sup&gt;®&lt;/sup&gt;