Synthesis of 2-Amino-2-deoxy-1,3-dithioidoglycosides via Organocatalytic Relay Glycosylation of 3-O-Acetyl-2-nitrogalactals.

Idose-type glycosides have numerous biological activities and have been widely used as anticoagulant drugs and anti-infection drugs. Thioglycosides have enhanced stability for acid-mediated or enzymatic hydrolysis, and have a wide range of applications in glycobiology and drug development. Herein, we describe an efficient method for site-selective and stereoselective synthesis of potential bioactive 2-amino-2-deoxy-1,3-dithioidoglycosides via organocatalysis sequential C3-Ferrier rearrangement and Michael addition of 3-O-acetyl-2-nitrogalactals. Both stepwise and one-pot protocols were carried out and work well. This unique thio-glycosylation protocol highlighted the various advantages, including (i) mild reaction conditions; (ii) excellent site-selectivity and stereoselectivity, good to excellent yields; (iii) broad substrate scopes; (iv) being atom-economic and environmentally friendly; (v) the reactions can be scaled up. [ABSTRACT FROM AUTHOR]