Solid-Phase Synthesis of Lactose-Containing Oligosaccharides

The new lactosyl donor 8, bearing an Fmoc-protected hydroxy group, has been prepared from lactose for the solid-phase synthesis of lactose-containing oligosaccharides. In addition to the preparation of 3b-O-fucosyllactoside 1 (with donor 4), use of this new building block has permitted the syntheses of 3b-O-mannosyllactoside 2 and of human milk oligosaccharide lacto-N-tetraoside 3, with known donors 5 and 6, respectively. These successful, high-yielding syntheses demonstrate the usefulness of Fmoc-protected O-glycosyl trichloroacetimidate 8 for the solid-phase construction of oligosaccharides, by an ester-type linker strategy.