[Synthesis of determinant oligosaccharides of the ABH (type 1) blood group antigen and Leb tetrasaccharide from a common precursor].

Synthesis of blood group ABH (type 1) determinant oligosaccharides and Leb tetrasaccharide has been performed using the same trisaccharide precursor-benzyl 2-acetamido-4,6-O-benzylidene-[4,6-O-benzylidene-2-O-[2-O-benzyl-3,4-di- O- (4-nitrobenzoyl)-alpha-L-fucopyranosyl]-beta-D-galactopyranosyl]-2-deoxy - alpha-D-glucopyranoside. A- and B-determinants were prepared by alpha-galactosaminylation and alpha-galactosylation of the title trisaccharide, respectively. Leb-determinant was synthesized by a series of simple blocking and deblocking steps followed by alpha-fucosylation.