Glycosidation Trichloroacetonitrile

Trichloroacetonitrile reacts with glycosidic hydroxy groups of protected sugars to form glycosyl trichloroacetimidates (R. R. Schmidt, 1980, 1984,1985,1986 B. Wegmann, 1988). The imidate is substituted by alcohols in the presence of trimethylsilyl trifluoromethanesulfonate... 

Glycosidation Allyl chloroformate, 9 Boron trifluoride etherate, 43 Silver(I) tetrafluoroborate, 273 Silver (I) trifluoromethanesulfonate, 274 Thallium zeolites, 296 Tin(II) trifluoromethanesulfonate, 301 Trichloroacetonitrile, 321 Grignard reactions and reactions of... 

Trichloroacetonitrile, 321 C-Glycosides Allyltrimethylsilane, 11 Organoaluminum reagents, 202 Silver(I) trifluoromethanesulfonate,... 

Among all the synthetic methods developed for glycosidic bond formation, the trichloroacetimidate method developed by Richard Schmidt and coworkers [18] is probably the most popular and widely used for the synthesis of complex oligosaccharides. Glycosyl trichloroacetimidates can be readily prepared by a base-catalyzed addition of the anomeric hydroxy group to trichloroacetonitrile. The stereochemistry can be influenced by the addition of different bases the use of K2C03 favors formation... 

Carbohydrate trichloroacetimidates have become very useful derivatives for the activation of the carbohydrate moiety. The carbohydrate can be readily transferred to form many types of glycosides [78]. Glycosides are readily formed by reaction of the hemiacetal hydroxyl with trichloroacetonitrile under base catalysis conditions. The p-anomer is rapidly and preferentially formed first as a favored kinetic product. Under base catalyzed conditions, however, it is slowly anomerized to give the a-anomer, which is the more stable thermodynamic product, due to the anomeric effect (reaction 4.63). Thus, either the a- or the P-anomer can be isolated in pure form and in high yield, depending on the length of time that the reaction is allowed to proceed. 

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