Synthesis of oligosaccharides of biological importance

Syntheses of a variant of myo-inositol-containing compounds are discussed and described, including glycan phosphatidylinositol structures found on various cell surfaces and believed to play important roles in the life cycles of tropical parasites (Trypanosoma and Leishmania) and in the action of insulin, and phosphatidyl inositol phosphates, known signal substances in a number of biological events. The resolution of myo-inositol is performed using camphor acetals and the phosphohester linkages are introduced using H-phosphonates. myo-Inositol appears widely in Nature, most frequently as phosphorylated or phospholipid derivatives, but 0-methyl and glycosyl inositols have also been identified and synthesized (ref. 1 and 2). The discovery that inositol derivatives containing phosphates, phospholipids, glycans or glycan hund prciteins are involved or act as "second messengers" in various cell regulation systems, has dramatically increased the interests in these compounds (ref. 3 and 4). Most eukaryotic cells utilize glycosyl phosphatidylinositols (GPIs) to anchor proteins to the cell membrane. Partial structural data, accumulated for over 100 GPI membrane-anchored proteins from a variety of organisms, have led to the proposal of the generalized anchor structure depicted in Fig. 1.