Glycosylation agents

The efficiency of this approach could be demonstrated in a-fucosylation with donor 32a and the acceptors 19C and 33A-D (Table XXXIII). Thus, with the help of this inverse procedure, the versatile building blocks for syntheses of the Lea, Le, Ley, and H antigen determinants are readily accessible (176). Presumably, this procedure may become of general importance when reactive glycosylating agents are employed. Alternatively, the reactivity of the fucosyl donor could be decreased, as has been recently proven very successfully (177). 

As acylation of aldonolactones is related to -elimination reactions, the fully acylated aldonolactone derivatives are mentioned in Section IX (see also Sections VI and VIII). Only a few studies on selective acylation of aldonolactones have been described. The partially acylated derivatives have been employed as glycosylating agents or for the preparation of monometh-ylated sugars. 

With the development of novel, powerful, and selective glycosylating agents,35 exemplified by the introduction of glycosyl trichloroacetimidates36 to... 

Gildersleeve and coworkers have suggested that the formation of a sulfenate(IX) can be competitive with glycoside formation this has been confirmed by characterization of reaction products generated at low temperatures (-78°C).18 The sulfenate itself becomes a glycosylating agent at higher temperatures (-20-20°C). This is consistent with earlier reports that the activated sulfoxide appears to be extremely reactive at -78°C (oxycarbenium ion, V) and yet stable at room temperature (sulfenate, IX).1... 

Glycosides, synthesis of, 64, 2 Glycosylating agents, 68, 2 Glycosylation on polymer supports, 68, 2 Glycosylation, with sulfoxides and sulfinates, 64, 2... 

Stable Analogs of Clycosyl Phosphates, the Main Glycosylating Agents and Metabolic Regulators... 

N. K. Kochetkov, L. V. Backinowsky, and Y. E. Tsvetkov, Sugar thio-orthoesters as glycosylating agents, Tetrahedron Lett., 18 (1977) 3681-3684. 

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