Revisiting the armed-disarmed concept: the importance of anomeric configuration in the activation of S-benzoxazolyl glycosides

The unexpectedly high reactivity of a (2-benzoxazolyl) per-O-benzoyl-beta-D-thioglucoside and related donors in reactions promoted by copper(II) trifluoromethanesulfonate is revealed, by comparison with the unreactive alpha-anomer, to be the result of neighboring group participation. Revision of the armed-disarmed concept for glycosyl donors is not required.