Glycosyl groups, removal

Nashed and Anderson [155] prepared an isomer of the blood-group B (type 2) tetrasaccharide with lactosamine substituted at the 4 -position with an a-D-galactosyl residue and at the 2 -position with an a-L-fucosyl residue. For this purpose, the lactosamine derivative (331), prepared via (330), was a-glycosylated with tetrabenzyl-galactosyl bromide in the presence of silver carbonate and silver triflate and the benzoyl group removed from the product so that the 2 -position could be fucosylated with the bromide (302) in the presence of bromide ion. If the fucose residue was added first to the lactosamine derivative (332), then the product (333) [which was converted into the trisaccharide of the blood group H (type 2)] would not react with the tetrabenzyl-galactosyl bromide. 

Pleuss, N, Kunz, H, A-Glycosyl amides removal of the anomeric protecting group and conversion into glycosyl donors, Angew. Chem. Int. Ed., 42, 3174-3176, 2003. 

Alkali fusion of bergenin results in the complete removal of the glycosyl group, with the formation of 4-0-methylgaIlic acid. ... 

The use of Fmoc-hydrmylamine 108 under similar conditions is also feasible for this glycosylation. After removal of the N-Fmoc group, glycosylo5Q amines 109 were readily prepared (Scheme 22). ... 

This ester was designed as a protective group for the 2-position in glycosyl donors. It has the stability of the benzoate during glycosylation, but has the ease of removal of the chloroacetate. It is readily introduced through the acid chloride... 

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