Schmidts trichloroacetimidate glycosidation

Lewis acid-promoted glycosidation of trichloroacetimidates with alcohols or phenols. 

Name Reactions A Collection of Detailed Mechanisms and Synthetic Applications, DOI 10.1007/978-3-319-03979-4 245, Springer International Publishing Switzerland 2014 

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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... 

Schmidt, R. and Kinzy, W. (1994) Anomeric-oxygen activation for glycoside synthesis the trichloroacetimidate method. Adv. Carbohydr. Chem. Biochem. 50,21. 

Scheme 8.2 Control of anomeric selectivity in glycosidations via Schmidt s trichloroacetimidate method.

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... 

Both assembly of the methyl glycoside 66 (see Scheme 29) and coupling of the appropriately protected trichloroacetimidate derivative 96 with the calicheami-cinone y precursor97 [222] (Scheme 37) using Schmidt s protocol [170c] were... 

Urban, F J, Moore, B S, Breitenbach, R, Synthesis of tigogenyl 3-0-cellobioside heptaacetate and glycoside tetraacetate via Schmidt s trichloroacetimidate method some new observations. Tetrahedron Lett., 31, 4421-4424, 1990. 

Abdel-Rahman, A A H, Winterfeld, G A, Takhi, M, Schmidt, R R, Trichloroacetimidate as a leaving group in the Ferrier rearrangement highly stereoselective synthesis of pseudogalactal glycosides, Eur. J. Org. Chem., 713-717, 2002. 

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