Iodine-Mediated α-Sulfonyloxylation of Alkyl Aryl Ketones with Oxone® and Sulfonic Acids

Alkyl aryl ketones are converted into the corresponding α-sulfonyloxyketones, in moderate to excellent yields, via a novel procedure that utilizes Oxone^®, p-toluenesulfonic acid or methanesulfonic acid and molecular iodine in a mixture of acetonitrile and 2,2,2-trifluoroethanol. The yield is found to be dependent on the nature of the ketone. A mechanism is proposed in which the key intermediates are an α-iodoketone and a subsequently formed α-iodosylketone. The latter reacts with the sulfonic acid to afford the α-sulfonyloxyketone product.