A complementary concept for superarming glycosyl donors through the use of common protecting groups was previously discovered with S-benzoxazolyl (SBox) glycosyl donors. As this strategy can be of benefit to existing oligosaccharide methodologies, it has now been expanded to encompass a wide array of common, stable glycosyl donors. The versatility of this developed technique has been further illustrated in application to a sequential chemoselective oligosaccharide synthesis, wherein a superarmed ethyl thioglycoside was incorporated into the conventional armed-disarmed strategy.

Traditional strategies for oligosaccharide synthesis often require extensive protecting and/or leaving group manipulations between each glycosylation step, thereby increasing the total number of synthetic steps while decreasing both the efficiency and yield. In contrast, expeditious strategies allow for the rapid chemical synthesis of complex carbohydrates by minimizing extraneous chemical manipulations. The armed–disarmed approach for chemoselective oligosaccharide synthesis is one such strategy that addresses these challenges. Herein, the significant improvements that have recently emerged in the area of chemoselective activation are discussed. These advancements have expanded the scope of the armed–disarmed methodology so that it can now be applied to a wider range of oligosaccharide sequences, in comparison to the original concept. Surveyed in this chapter are representative examples wherein these excellent innovations have already been applied to the synthesis of various oligosaccharides and glycoconjugates.

A novel glycosyl donor that combines the concepts of both conformational and electronic superarming has been synthesized. The reactivity and selectivity of the donor has been tested in competition experiments.

The profound effect of substituents at C-5 of glycosyl sialosides on their stereoselectivity is well-known although the exact nature of this effect is somewhat less understood. Presented herein is a comparative study of a range of novel sialyl donors with various O-substituents. It is demonstrated that O-substituents at C-4 and C-7 may also have a significant effect on the reactivity of sialyl donors and on the stereoselectivity of chemical sialylation.