Chlorodeoxy sugars preparation

The Preparation of Chlorodeoxy Sugars by Reaction with Sulfuryl Chloride... 

J. K. N. Jones and his colleagues have extensively studied the reaction of sulfuryl chloride with carbohydrates.21-29 This work has elucidated the stereochemical principles involved in the various transformations, and has made available a convenient and effective procedure for the preparation of chlorodeoxy sugars. Several examples of the utility of such derivatives, obtained by way of a reaction with sulfuryl chloride, in the synthesis of other rare sugars are discussed in Section III (see p. 281). In the present Section, the studies on the reaction itself are surveyed. 

An investigation of the reduction of chlorodeoxy sugars with lithium aluminum hydride has been reported.68 In one experiment, 3-deuterio-l,2 5,6-di-0-isopropylidene-a-D-allofuranose (197) was prepared, and converted into 3-chloro-3-deoxy-3-deuterio- l,2 5,6-di-0-isopropyl-idene-a-D-glucofuranose (198) by treatment with triphenylphos-phine-carbon tetrachloride reduction with lithium aluminum hydride gave 3-deoxy-3-deuterio-1,2 5,6-di-O-isopropylidene-a-D-r/foo-hexofuranose (199), a result which established that the reduction must have occurred with, retention of configuration at C-3. 

The reaction of carbohydrates with sulfuryl chloride can form chlorosulfate groups initially, followed by Sn2 displacement of the liberated chloride ion. This provides another effective method for the preparation of chlorodeoxy sugars [34,53]. Those positions, where the steric and polar factors are favorable for a Sn2 reaction, are more susceptible to displacement. The chlorosulfates that have been substituted with a chloride can easily be cleaved by treatment with sodium iodide. 

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