Synthesis of N-acetyllactosamine based branched hexasaccharide

The protected spacer-armed branched tri-N-acetyllactosamine has been synthesized as a building block for the synthesis of biantennary ABH blood group antigens. The key synthetic step is the simultaneous glycosylation of the 3′- and 6′-OH groups of an N-acetyllactosamine glycosyl acceptor by N-Troc-lactosamine trichloroacetimidate.