[liuj975]

Could any nice guy tell me the mechanism of this reaction (attachment)?

[Doc Oc]

Take a look at this paper.  Although they use IBX and not BAIB, the concept remains the same.

http://pubs.acs.org/doi/abs/10.1021/ja012127%2B?journalCode=jacsat

[orgopete]

I expect this is written erroneously. I think it probably is 1) PhI(OAc)2 and 2) Zn. Otherwise I might think the zinc would reduce the iodonium salt. I don't think that is the reaction.

I think this is a two step process. First oxidation of the sulfur and reduction of the (oxidized) ketene thioacetal. Can you make a suggestion if that is the process?

Even if I am wrong (which could be), it may still be easier to understand the reaction if you drew it as a two step process.