Stereoselective synthesis of α-linked 2-deoxysaccharides and furanosaccharides by use of 2-deoxy 2-pyridyl-1-thio pyrano- and furanosides as donors and methyl iodide as an activator
A practical and highly stereoselective glycosidation methodology is described, where anomeric mixture of 2-deoxy 2-pyridyl-1-thiopyranoside donors (1–3, 27) have been coupled with several sugar alcohols (4–8,29,31) on activation by methyl iodide to obtain axiallylinked2-deoxysaccharides (9–17,30,32,33). Application of this method for the synthesis of disaccharide fragment 28 of avermectin is also