Synthesis of S-and C-galactofuranosides via galactofuranosyl iodides

MARINO C.; BALDONI L.

Madrid

Simposio; XXVI International Symposium of Carbohydrates; 2012

The important role of carbohydrates and glycoconjugates in biochemical processes has promoted the development of glycomimetics as tools for studying these processes and as potential therapeutic agents. These analogs, in which one or more oxygen atoms of the sugar have been replaced by a carbon, sulfur, or other heteroatoms, are very similar to the natural substrates in most of their biological properties and conformations but also present some useful differences.1 For example, they can interact with the active site of glycosidases, but be resistant to the hydrolysis. Our interest in the D-Galf glycobiology led us to study the synthesis of compounds 5 and 6, as galactofuranosyl mimetics. 1-Thioglycopyranoses are valuable building blocks for the construction of thiodisaccharides. However, the synthesis of galactofuranosyl analogues such as 3 or 5 was not described. On the other hand, the synthesis of C-galactofuranosides, as 4 and 6 was scarcely reported. In our laboratory we developed an O-galactofuranosylation methodology from the persilyl precursor 1, via the iodide 2.2 This methodology, with slight modifications, was suitable for the preparation of 3 and 4. We studied the potential of 3 as glycosyl donor, by Michael addition to an enone. Compounds 4 and 6 are also useful for their potential for conjugation reactions.