Chapter 6

Conclusion

An orthogonal glycosylation strategy was developed by combined use of phenylthioglycosides and glycosyl fluorides both as donors and acceptors. Using this strategy, chito-oligosaccharide and branched blood group tetrasaccharide were synthesized in a highly efficient manner, respectively. [12, 20] A single building block was used to constract chito-heptaose derivative. Also, extra manipulations required during the synthesis, such as temporary protection of the anomeric position and subsequent conversion into donor are thus eliminated. Synthesis of a branched oligosaccharide with four different types of glycosidic linkages was achieved using four suitably protected monosaccharide units in shortest steps possible (seven steps, 38% overall yield).