Synthesis of Sialyl Glycosides

Regio- and a-Stereoselective Sialyl Glycoside Syntheses Using Thioglycosides of Sialic Acids in Acetonitrile 359 

Since 1965, a number of attempts for obtaining sialyl glycosides have been achieved [15,16], mainly by the classic Koenigs-Knorr method using Al-acetylneuraminyl halides 2 as glycosyl donors. However, the yield and stereoselectivity of the glycosides with sugar 

The use of 2-halo-3-(3-substituted neuraminyl derivatives 3 is an efficient approach for overcoming these difficulties [17,18] and, in fact, many attempts have been reported [15,19. However, additional multiple steps for preparation of glycosyl donor and removal of the C-3 substituent to arrive at the desired products are required, even though improvements in the yield and stereospecificity of the glycosides are achieved. 

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