Use of the anomeric centre as a nucleophilic species

The anomeric centre is, by virtue of the ring oxygen an electrophilic species, and is thus employed as such in numerous O-glycosidation strategies. However, the C-1 carbon can actually be converted to a nucleophilic centre, providing apowerfiil tool for C-glycoside synthesis. 

Further methods involving reductive lithiation exploit anomeric sulfones which also lead to the formation of (3-C-glycosides [20]. Since C-1-lithiation of carbohydrates traditionally results in l,2-(3-elimination, to afford the corresponding 

The method of Kessler can also be adapted to generate 3-glycosides. Sinay had previously shown that transmetallation of organostannanes to the organolithium species occurred with retention of stereochemistry and that the subsequent reaction with electrophiles was stereoselctive [22]. Kessler was able to generate 

In addition, the method can also be adapted to incorporate iV-acetyl groups at the C-2 position, a functionality which is frequently found in nature [23]. 

Round-bottomed flask with rubber septum plus magnetic stirrer bar 

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