Synthesis of Serine-Linked Phosphatidylinositol Mannosides (PIMs)

The 6‐O‐allyl group of inositol mannoside (D)‐6 was used for the generation of O‐linked serine residues via a sequence of dihydroxylation, selective 3′′‐O‐protection, introduction of the 2′′‐amino group, deprotection, and oxidation of the 3′′‐position. Attachment of the phosphatidyl residue to 1‐O of the inositol moiety and complete deprotection furnished target molecules (D)‐1 and (D)‐2. Alternatively, instead of introduction of a 6‐O‐allyl group, 2′′,3′′‐dihydroxy propanylation of the 6‐O‐position of the inositol moiety using a silyl‐protected cyclic sulfate of glycerol was possible. Thus, target molecule (L)‐3 was obtained. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)