Highly chemoselective synthesis of aryl allylic sulfoxides through calcium hypobromite oxidation of aryl allylic sulfides

A highly chemoselective oxidation of widely substituted aryl allylic sulfides, prepared by allylation of arylthioethers with KF-Celite, to the corresponding aryl allylic sulfoxide was achieved by employing calcium hypobromite. Neither over-oxidation to sulfones nor halogenation of the aromatic rings was observed. The protocol may be successfully applied for the oxidation of substituted allylic systems (i.e., 2-haloallyl) that per se could interact with the oxidizing agent.