Chemical Forums
Chemistry Forums for Students => Organic Chemistry Forum => Organic Chemistry Forum for Graduate Students and Professionals => Topic started by: Babcock_Hall on April 20, 2022, 11:21:17 AM
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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?
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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.
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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.