Synthesis of blood group pentasaccharides ALey, BLey and related tri- and tetrasaccharides

Pentasaccharides GalNAcα1-3(Fucα1-2)Galβ1-4(Fucα1-3)-GlcNAc (ALe^y) and Galα1-3(Fucα1-2)Galβ1-4(Fucα1-3)-GlcNAc (BLe^y), as well as forms GalNAcα1-3Galβ1-4(Fucα1-3)GlcNAc and GalNAcα1-3Galβ1-4GlcNAc were synthesized as molecular tools for studying natural antibodies directed against blood group A and B antigens.