Primary activation by Lewis acids

Thioglycosides and 4-pent-l-yl glycosides are inert to activation with Lewis acids. Consequently, all donors that can be activated by treatment with a suitable Lewis 

In summary, sulfides, selenides, or 4-penten-l-yl glycosides in combination with halides, trichloroacetates or sulfoxides, have been shown to be ideal building blocks 

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