Synthesis of 4,5-disubstituted-3-deoxy-d-manno-octulosonic acid (Kdo) derivatives

In this study, a new synthetic approach to 4,5-branched Kdo trisaccharides based on the common acceptor Kdo(α2-4)Kdo was developed. The synthesis of three types of 4,5-branched trisaccharides, Hep(α1-5)[Kdo(α2-4)]Kdo, Man(α1-5)[Kdo(α2-4)]Kdo, and GalNAc(α1-5)[Kdo(α2-4)]Kdo, was achieved in good yield and high α-selectivity.