β-Arabinofuranosylation Using 5-O-(2-Quinolinecarbonyl) Substituted Ethyl Thioglycoside Donors

A new beta-stereoselective D- and L-arabinofuranosylation method has been developed employing 5-O-(2-quinolinecarbonyl) substituted arabinosyl ethyl thioglycosides as glycosyl donors. The approach allows a wide range of acceptor substrates to be used; the beta-selectivity is good-to-excellent. Stereoselective synthesis of a mannose-capped octasaccharide portion from a mycobacterial cell wall polysaccharide was then carried out to demonstrate the utility of this methodology.