The first example of a singlet oxygen induced double bond migration during sulfide photooxidation. Experimental evidence for sulfone formation via a hydroperoxy sulfonium ylide.

The first example of the formation of a sulfone concomitant with double bond migration during photooxidation of a sulfide is reported. Evidence is presented which demonstrates that the double bond migration is not a result of a prior acid-catalyzed rearrangement of an unrearranged sulfone precursor. This unusual observation is used to argue that the sulfone is formed via rearrangement of a hydroperoxy sulfonium ylide intermediate.