Thioethers from carbocations

Chemoselective oxidation of 3-arylsul-fenylmethyl-A -cephem affords 3-meth-oxymethyl-A -cephem in an anodic substitution. From the two thioethers, the arylthio group is more easily oxididized to a radical cation, that then undergoes cleavage to a thiyl radical and a carbocation (Fig. 31) [152]. 

---