Abstract tert-Butyldimethylsilyl 2-azido-4, 6-O-benzylideneglucopyranoside 5 proved to be a versatile starting material for the synthesis of the Le x antigen family. 3-O-Fucosylation of 5, ensuing reductive benzylidene ring cleavage, and then 4-O-galactosylation afforded Le x trisaccharide building block 12 which was readily converted into trisaccharide donor 14α, β and into trisaccharide 3c-O-acceptor 16. Their reaction in acetonitrile as solvent at low ...
