Use of Iminoesters and Sulfonylchlorides

SCHEME 6.19 Chlorosulfate ester conversion of a secondary hydroxyl group to a chloride. 

SCHEME 6.21 Direct conversion of a primary hydroxyl group to a chloride using methanesulfonyl chloride. 

While further examples of these reactions are not presented here, these reactions (among others) were extensively cataloged by Larock [32] with respect to general organic chemistry. As such, it is important to note that while the literature may not frequently present these reactions in the context of carbohydrate chemistry, they are nonetheless extremely valuable tools for the introduction of halides to sugar ring systems. 

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