Synthesis of Allyl 3-Deoxy-d-manno-2-octulopyranosidic Acid 4-Phosphates and 5-Phosphates

Allyl glycosides (ketosides) of pyranosidic 3-deoxy-D-manno-2-octulosonic acid (Kdo), phosphorylated at either positions 4 or 5 were synthesized with the aim to study the biological properties of phosphorylated Kdo. The alpha- and beta-allyl glycosides prepared from a pyranosidic fluoride of diisopropylidene Kdo were protected at the 7- and 8-positions, and then O-phosphorylated at the 4- or 5-position by the phosphoramidite procedure. Separation of the positional isomers followed by deprotection afforded four compounds in pure states.