Synthesis of α-S-glycosphingolipids based on uronic acids.

The synthesis of S-glycosphingolipids based on uronic acids is described. These compounds are analogous to the highly immunostimulatory antigens isolated from the cell walls of bacteria of the Sphingomonas family. Key to the synthetic route is a stereoselective anomerization to give α-glycosyl thiol precursors. A route to a sphinganine precursor from pseudoephedrine glycinamide is also described.