Glycosylations nucleophilic substitution, aglycone carbon

In a different approach to the preparation of glycosides, the nucleophilic substitution takes place at the carbon atom of the aglycone rather than at the anomeric carbon (Scheme 4.53). In contrast to the methods discussed in Section 4.3, there is no scission of the glycosyl-oxygen bond in these reactions. Instead, the R-X bond is cleaved. 

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