Superarmed and Superdisarmed Building Blocks in Expeditious Oligosaccharide Synthesis

Abstract

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.

Conformationally superarmed S-ethyl glycosyl donors as effective building blocks for chemoselective oligosaccharide synthesis in one pot

“…5 Beyond the traditional scope of the armed-disarmed strategy, superarmed and superdisarmed building blocks have also been identified and studied. 6 Bols and co-workers developed an approach to superarm glycosyl donors by changing the equatorial-rich 4 C 1 conformation to an axial-rich conformation. 7 These conformational changes were induced by creating steric congestion with tert -butyldimethylsilyl (TBS) or related bulky protecting groups at the C-2, 3 and 4 positions of S -phenyl (SPh) glucosides, resulting in a skew-boat conformation.…”

Synthesis of an α-Amylase Inhibitor: Highly Stereoselective Glycosidation and Regioselective Manipulations of Hydroxyl Groups in Carbohydrate Derivatives

“…The C unit 14b can prepared from 19, the synthesis of which from diacetone-glucose (6) has been reported and applied in the first-generation method. 13 The synthesis of 19 from D-xylose (20) was attempted in pursuit of a more efficient method for the C unit (Scheme 3).…”

A study of silver (I) perchlorate as an effective promoter for chemical glycosylation with thioimidates and thioglycosides

“…The key findings of this study are summarized in Table 2. As a direct continuation of our preliminary work, we set up a series of experiments with 2-O-benzyl-3,4,6-tri-O-benzoyl-protected (superdisarmed) 43 thioimidoyl donors. First, we performed glycosylation of the secondary glycosyl acceptor 5 35 with SBox donor 1.…”