Glycosidic ether oxygens synthesis

Intramolecular activation of benzyl ethers can lead to unexpected but highly selective deprotection. In the example in Figure 2.12 [22], the proximity of the 2-oxygen to the allyl group led to its capture by the intermediate iodonium ion and loss of benzyl as benzyl iodide reductive elimination of the so-formed iodomethyl tetrahydrofuran completed the process which was used as a key step during a synthesis of mannosamine and glucosamine C-glycosides. 

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