Synthesis of phosphatidylinositol mannosides (PIMs)

Two strategies towards the synthesis of phosphatidylinositol mannosides (PIMs) were elaborated which permit selective access to the O-1-, O-2-, and the O-6 position of the myo-inositol residue. Starting materials are 1,2:5,6- and 1,2:4,5-di-O-cyclohexylidene-DL-myo-inositol, respectively. In the latter case, the required assignment to the D- or L-series is based on the transformation of one enantiomer into known (-)-liriodentritol. The efficiency and potential versatility of the two approaches is exemplified in the synthesis of PIMs (D)-1a and its pseudoenantiomer (L)-1b, both having myristoyl residues as part of the phosphatidyl moiety.