Synthesis of 1 and 2a is described using a block synthetic strategy. Compound 4 was used as precursor for the two mannose derivatives which, coupled together, forms the dimannoside building block. Thioglycoside 7 was coupled to 8 yielding inositol phosphoglycan 9a, which was selectively deprotected and reacted with 2,3,4,6-tetra-O-benzyl-a-D-glucopyranos-1-yl H- phosphonate to form the protected target molecule 12. Deprotection of 12 by acidic deacetalisation/desilylation and subsequent catalytic hydrogenolysis resulted in cleavage of the anomeric phosphodiester to produce 1. Debenzylation with sodium in liquid ammonia followed by acidic deacetalisation/desilylation gave the target compound 2a. (C) 2000 Published by Elsevier Science Ltd.

Total synthesis of the core heptasaccharyl myo-inositol, Galp(a1-6)Galp(a1-3)Galf(ß1-3)[Glcp(a1-PO4-6)Manp](a1-3)Manp(a1-4)GlcN p(a1-6)Ins-1-PO4, and the corresponding hexasaccharyl myo-inositol, Galp(a1-6)Galp(a1-3)Galf(ß1-3)Manp(a1-3)Manp(a1-4)GlcNp(a1-6)Ins-1-PO4 , found in the lipophosphoglycans of Leishmania parasites are described. The target molecules contain synthetic challenges such as an unusual internal galactofuranosyl residue and an anomeric phosphodiester. The synthesis was accomplished using a convergent block synthetic strategy. Four building blocks, a trigalactoside, a dimannoside, a glucosyl inositolphosphate, and a glucosyl-a-1-H-phosphonate, all appropriately protected, were used. The trigalactoside was linked to the dimannoside followed by glycosylation with the glucosyl inositolphosphate to produce the fully protected hexasaccharyl myo-inositol. Subsequent oxidative coupling of the glucosyl-H-phosphonate formed the anomeric phosphodiester linkage to produce the protected heptasaccharyl myo-inositol. Both the assembly order of the subunits and sequence of deprotection were essential for the successful synthesis of these complex molecules. The deprotection was accomplished by deacetylation and clevage of benzyl ethers with sodium in liquid ammonia, followed by acidic deacetalization/desilylation to produce the target molecules.

Short synthetic routes to protected derivatives of 2-amino-2-deoxy-a-D-glucopyranosyl-(1?6)-D-myo-inositol are described. Various 2-azido-2-deoxy-glucosyl donors were synthesized, starting from D-glucal or glucosamine hydrochloride. Derivatives of 1,2- and 2,3- D-myo-inositol-camphanylidene acetals were prepared to function as glycosyl acceptors. The subsequent glycosylations produced useful building blocks for the synthesis of GPI-anchor substances. © 2002 Elsevier Science Ltd. All rights reserved.

Synthesis of three galactoglycerolipids (3-O-(ß-D-galactopyranosyl)-1-O-hexadecyl-2-O-palmitoyl-sn-glycerol, 3-O-(a-D-galactopyranosyl-(1?4)-ß-D-galactopyranosyl)-1-O- hexadecyl-2-O-palmitoyl-sn-glycerol, 3-O-(a-D-galactopyranosyl-(1?4)-ß-D-galactopyranosyl)-1-O- hexadecyl-sn-glycerol), and the corresponding glycerolipid (1-O-hexadecyl-2-O-palmitoyl-sn-glycerol) is described. The first two compounds were recently identified in the human colon carcinoma cell line HT29. The three-carbon synthon (S)-glycidol was used for construction of the glycerol moiety. Glycosylation of (S)-glycidol with protected galactosyl and digalactosyl donors produced galactosyl and digalactosyl glycidols. Lewis acid catalyzed opening of the epoxide produced protected galactosyl and digalactosyl glycerolipids. Deprotection, or palmitoylation followed by deprotection, yielded the target compounds. The corresponding glycerolipid was synthesized analogously and an oxidation-reduction procedure for tritiation was developed. The synthesized compounds will be used in studies of the role of galactosyl glycerolipids in differentiation and colon cancer development. © 2002 Elsevier Science Ltd. All rights reserved.

New efficient routes to enantiopure phospholipids, starting from (S)-glycidol, are described. Lysophosphatidic acids and phosphatidic acids were obtained in good overall yields from (S)-glycidol, in only three and four steps, respectively. Moreover, the strategy can also be used to produce phosphatidylcholines in three steps. Using dialkylphosphoramidites, (S)-glycidol was phosphorylated to give (R)-1-O-glycidyl dialkyl phosphates. Regiospecific epoxide opening, using hexadecanol or cesium palmitate, followed by phosphate deprotection, provided lysophosphatidic acids. 2-O-Esterification prior to phosphate deprotection provided 1,2-O-diacyl and 1-O-alkyl-2-O-acyl phosphatidic acids. Phosphorylation of (S)-glycidol using phosphorus oxychloride followed by in situ treatment with choline tosylate produced (R)-glycidyl phosphocholine. Subsequent nucleophilic opening of the epoxide using cesium palmitate produced 1-O palmitoyl-sn-glycero-3-phosphocholine, which has been used in syntheses of phosphatidylcholines.