Stereoselective glycosidations and application to the mycobacterial arabinogalactan by gold iii catalysis

Abstract

Glycoconjugates are important for variety of intracellular and extracellular biological events Synthesis of glycoconjugates is still a formidable task in spite of various developments over the last one century Activation of propargyl glycosides with catalytic amount of gold III salts has emerged as a new efficient and powerful alternative and it has been widely used to synthesize wide spectrum of glycosides In addition stereoselective glycosidation is more challenging and locking of C1 C2 positions as orthoesters is one of the best options Propargyl 1 2 orthoesters are investigated for the synthesis of glycomonomers such as glyco acrylates acrylamides 1 6 anhydro sugars and aminooxyglycosides These methodologies have been gauged with a diverse panel of substrates and found the products of the glycosidation are pure enough to undergo polymerizations easily Salient features of these methods are i catalytic ii easy purification and iii high yielding In yet another effort propargyl 1 2 orthoesters are exploited for the stereoselective synthesis of 1 2 trans furanosides under gold catalysis repertoire Resulting 1 2 trans furanosides were shown to undergo epimerisation at C 2 position by oxido reduction to afford 1 2 cis glycosides in a bio inspired manner Identified protocols were effectively utilized for the synthesis of pentadodecafuranosyl arabinogalactan of Mycobacterium tuberculosis cell wall Details of the research work carried out over the last five years will be presented in the thesis newline newline