[Babcock_Hall]

We have used Oxone for thioether oxidations in the past, but I am concerned that the acidity of this reagent may cause hydrolysis of our glycosididic bond (we have an acetyl-protected glycoside with a spacer between it and the sulfur).  I have seen mCPBA used in a 2005 paper for a very similar transformation; therefore, it would be my first choice.  I have also seen dimethyl dioxirane used in a similar reaction.  I have also read that Oxone can be buffered with borate (I can provide a reference if anyone is interested).  The other oxidants that might be tried are NaWO₄•2H₂O/H₂O₂ and KMnO₄.  My question is why doesn't mCPBA cause cleavage of the glycosidic bond.  Is it because the reaction is done under anhydrous conditions?

[Babcock_Hall]

The reference to buffering Oxone with borate to about pH 5 is Trost BM, Acemoglu M Tet Lett 1989 30 1495.  Right now my thoughts are to try mCPBA first; if that fails, I would try buffered Oxone second.

[Babcock_Hall]

We were successful in using mCPBA to convert a sulfide to a sulfone using mCPBA in the presence of a glycosidic bond.  Besides mCBPA, there is one other reagent in the literature that has been shown to be capable of this transformation, which IIRC is dimethyldioxirane.