Thioglycosides armed/disarmed concept

Transfer of the Armed-Disarmed Concept to Thioglycoside Glycosylation... 

The armed-disarmed concept is tranferrable to having thioglycosides both as donors and acceptors91,92 (Scheme 9). Anomeric activation can, in favorable instances, also be used for this purpose93 (Scheme 10). 

The armed-disarmed concept, although discovered with 0-pentenyl glycosides, has been found to be applicable to many other classes of glycosides such as thioglycosides [6], selenoglycosides [39], fluorides [40], phosphoroamidates [41], substituted thioformimidates [42], glycals [21], y-benzoxazolyl (SBox), and 5-thiazolinyl (STaz) [43, 44]. 

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... 

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