Activation of superoxide with boron trifluoride in dry acetonitrile can facilitate highly chemoselective and efficient oxidation of sulfides to corresponding sulfoxides at ice-water bath in excellent yields without any interference in the presence of ketone, olefin, ether, and hydroxyl functionalities. This new method also offers further advantages of a short reaction time, no overoxidation to sulfones, and none of complex catalysts and toxic metallic compounds used. A tetrafluorodiboronperoxide intermediate formed in situ from this new process is proposed.