title: Influence of Steric Crowding on Diastereoselective Arabinofuranosylations.
abstract: The occurrence of arabinofuranosides on the cell surface of Mycobacterium tuberculosis (Mtb) and their significance in controlling disease spurred interest in developing strategies for their diastereoselective synthesis. Mtb uses enzymes to achieve diastereoselectivity through noncovalent interactions. Of the two possible glycosidic linkages, chemically, 1,2-trans linkage is relatively easy to synthesize by taking advantage of neighboring group participation, whereas synthesis of the 1,2-cis linkage is notoriously difficult. In this article, stereochemical effects on the diastereoselectivity of arabinofuranosidation are investigated with thiopyridyl, imidate, and thiotolyl donors as well as differently crowded glycosyl acceptors; subtle differences in the stereochemical environment of the acceptors were observed to alter the diastereoselectivity of the furanoside formation. Results from this endeavor suggest that 1,2-cis arabinofuranosides can be synthesized conveniently by conducting the reaction at lower temperature on sterically demanding and less reactive substrates.
authors.affiliation: †Department of Chemistry, Indian Institute of Science Education and Research, Pune 411 008, India.
authors.forename: Maidul
authors.initials: M
authors.lastname: Islam
authors.affiliation: ‡Centre for Molecular Modelling, Indian Institute of Chemical Technology, Hyderabad 500 007, India.
authors.forename: Gaddamanugu
authors.initials: G
authors.lastname: Gayatri
authors.affiliation: †Department of Chemistry, Indian Institute of Science Education and Research, Pune 411 008, India.
authors.forename: Srinivas
authors.initials: S
authors.lastname: Hotha
mesh_terms: D001089:Arabinose / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000737:chemistry*; D015394:Molecular Structure; D009169:Mycobacterium tuberculosis / Q000737:chemistry / Q000166:cytology; D013237:Stereoisomerism
chemical_list: D001089:Arabinose