New Methods for the Synthesis of Glycosides and Oligosaccharides—Are There Alternatives to the Koenigs‐Knorr Method? [New Synthetic Methods (56)]

TLDR

Glycoproteins, glycolipids, and glycophospholipids are essential membrane components, and their oligosaccharide residues mediate intercellular recognition, immune reactions, and viral binding, prompting extensive research into glycoconjugate synthesis; the Koenigs‑Knorr method has been a major advance, but its disadvantages have spurred the search for alternatives. The article discusses new glycoside and oligosaccharide synthesis methods that clarify the molecular basis of glycoconjugate functions and derive new physiological principles. The discussion focuses on 1‑O‑alkylation, the trichloroacetimidate method, and activation via glycosylsulfonium salts and glycosyl fluorides.

Abstract

Abstract Glycoproteins, glycolipids, and glycophospholipids (glycoconjugates) are components of membranes. The oligosaccharide residue is responsible for intercellular recognition and interaction; it acts as a receptor for proteins, hormones, and viruses and governs immune reactions. These significant activities have stimulated interest in oligosaccharides and glycoconjugates. With their help it should be possible to clarify the molecular basis of these phenomena and to derive new principles of physiological activity. Major advances in the synthesis of oligosaccharides have been made by the use of the Koenigs‐Knorr method, in which glycosyl halides in the presence of heavy‐metal salts are employed to transfer the glycosyl group to nucleophiles. The disadvantages of this procedure have led to an intensive search for new methods. Such methods will be discussed in this article. Emphasis is placed on glycoside and saccharide formation by 1‐ O ‐alkylation, on the trichloroacetimidate method, and on activation through the formation of glycosylsulfonium salts and glycosyl fluorides.