Activated glycosyl donor

Friedel-Crafts coupling of an aromatic compound with an activated glycosyl donor is a classic, standard method for C-aryl glycoside synthesis [1,2]. Early interests were primarily centered at C-nucleoside synthesis, so that data were accumulated for the ribofuranosyl series with degradable aromatics to construct the nucleic base (Scheme 2) [5]. Equation (1)... 

Boons G-J, Grice P, Leslie R, Ley SV, Yeung LL. Dispiroketals in synthesis 5. A new opportunity for oligosaccharide synthesis using differentially activated glycosyl donors and acceptors. Tetrahedron Lett. 1993 34 8523-8526. 

Davis, B G, Wood, S D, Maughan, MAT, Towards an unprotected self-activating glycosyl donor system bromobutyl glycosides. Can. J. Chem., 80, 555-558, 2002. 

A new type of latent-active glycosyl donors, 2 -carboxybenxyl glycosides and their benzyl esters, have been recently introduced [62-64]. The active carboxylic acids are readily available from the latent benzyl esters by catalytic hydrogenation in the presence of ammonium acetate. In an example [62] shown in Scheme 5.24 the latent mannoside (136) was glycosylated with the active donor (135) to provide exclusively the p-linked disaccharide (137) in excellent yield. The latent... 

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