Thioglycosides anomeric activation/deactivation

However, with thioglycosides there is an additional possibility to change the reactivity, namely through changing the alkyl (aryl) group of the anomeric thiol. This anomeric activation/deactivation prospect might be compared to the reactivity dif-... 

Thus, it seems that the concept of anomeric electronic activation-deactivation at the anomeric center taking precedence over armed-disarmed in the remainder of the pyranose ring might have reasonable validity, but, in many instances, the difference in reactivity of the p-nitrophenyl thioglycoside versus the p-acetamidophenyl thioglycoside is not enough to make this work (Scheme 1l).94... 

An alternative could be steric activation-deactivation at the anomeric centers of the donor and acceptor. An example using this concept is shown in Scheme 12. In the electronic activation-deactivation concept, deactivated p-nitrophenyl thioglycosides can, after functioning as glycosyl acceptors, be transformed into... 

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