Copper (I) Catalyzed Homo- and Heterocoupling of Mono and Disaccharide Deoxy Sugar Based Terminal Alkynes to Synthesize Mimic Glycoconjugates

In this communication, we have reported a productive and cost-effective catalytic system containing copper (I) iodide (CuI) and 4-dimethyl aminopyridine (DMAP), used for the first time in homo- and heterocoupling of stereoselective alpha-2-deoxy monosaccharide propargyl glycosides and alpha-2-deoxy disaccharide propargyl glycosides respectively in acetonitrile (MeCN) afforded the mimic oligosaccharide based conjugated 1,3-diyne derivatives upto 96 % yield under aerobic condition at room temperature. The results proved that the symmetrical homo coupling are exclusively favoured following the Glaser-Hay reaction and on other hand we have successfully synthesized the unsymmetrical heterocoupled deoxy sugar based mimic oligosaccharide products in good to excellent yield. This reaction involved mild conditions, a wide substrate scope, and excellent functional group compatibility as well as less reaction time. In this article, a library of nine novel stereoselective deoxy sugar derived symmetrical and unsymmetrical coupled products have been synthesized and structures were determined by the H-1, C-13 & 2D NMR spectroscopy.