Synthesis of blood-group substances. Part 11. Synthesis of the trisaccharide O-α-D-galactopyranosyl-(1 → 3)-O-β-D-galactopyranosyl-(1 → 4)-2-acetamido-2-deoxy-D-glucopyranose

Targeted Glycosyl Donor Delivery for Site-Selective Glycosylation,1

“…4,5 The principle relies on the logistical deployment of "protecting groups" on the donor, and the effect can be engendered by electronic 6 or torsional 7 factors, the latter being elegantly demonstrated in recent reports from Crich and co-workers. 8 Glycosyl acceptors are the other partners in coupling reactions, and it is well-known that poly-hydroxyl substrates frequently display selectivity based on orientation, 9 hydrogen bonding, 10 etc. Both sets of selectivities are kinetically based.…”

“…The concept of armed/disarmed strategies for controlling oligosaccharide assembly, initially formulated in the context of n -pentenyl glycosides, was rapidly extended to other glycosyl donors and has become part of the fabric of synthetic carbohydrate chemistry. , The principle relies on the logistical deployment of “protecting groups” on the donor, and the effect can be engendered by electronic or torsional factors, the latter being elegantly demonstrated in recent reports from Crich and co-workers . Glycosyl acceptors are the other partners in coupling reactions, and it is well-known that poly-hydroxyl substrates frequently display selectivity based on orientation, hydrogen bonding, etc. Both sets of selectivities are kinetically based.…”

Formation of the Glycosidic Linkage

“…In this last regard, heavy metal salts other than those based on silver(I) have been of great use: the combination of mercury(II) bromide/mercury(II) oxide seems to offer the advantages of promotion (HgBr 2 , a synergistic effect) and acid acceptor (HgO). [99][100][101] Some examples of successful glycosidations under Koenigs-Knorr conditions follow: [102][103][104] A great deal of effort has been devoted to elucidating the mechanism of the Koenigs-Knorr reaction. [99][100][101] Some examples of successful glycosidations under Koenigs-Knorr conditions follow: [102][103][104] A great deal of effort has been devoted to elucidating the mechanism of the Koenigs-Knorr reaction.…”

Solid-Phase Synthesis of α-Gal Epitopes: On-Resin Analysis of Solid-Phase Oligosaccharide Synthesis with 19F NMR Spectroscopy

“…These saccharides are bound by human anti-Gal antibodies involved in hyperacute rejection of porcine organs in xenotransplantation . Derivatives of α-Gal epitopes have previously been prepared by chemoenzymatic and conventional solution-phase synthesis. − …”

“…45 Derivatives of R-Gal epitopes have previously been prepared by chemoenzymatic and conventional solution-phase synthesis. [45][46][47][48][49][50][51][52][53][54][55][56][57]…”