Convergent synthesis of a fully phosphorylated GPI anchor of the CD52 antigen

A fully phosphorylated GPI anchor (1) of the CD52 antigen was synthesized by a highly convergent strategy. After a trimannose and a phospholipidated pseudodisaccharide were prepared separately, they were coupled together to form the GPI core, which was then phosphorylated to introduce two phosphoethanolamine moieties in one step to afford CD52 GPI in its fully protected form. Finally, global deprotection of the product resulted in 1.