To oxidize sulfides to sulfones, we often use the recipe in Blumenkopf T. 1986 Synthetic Communications 16 139-146. This paper uses a slight excess of Oxone in the presence of 4:3 methanol/water. Just today I found a protocol that uses one equivalent each of sodium periodate and potassium permanganate, Purrington ST and Glenn AG 1985 Organic Preparations and Procedures International 17(3):227-30. According to the authors the periodate oxidizes the sulfide to a sulfide, and the permanganate oxidizes the sulfide to a sulfone. A number of other functional groups are not affected, including alkenes, 1° alcohols, and amides. The solvent was a mixture of acetone and water, and the yields were moderate to excellent.