Copper mediated iodoacetoxylation and glycosylation: effective and convenient approaches for the stereoselective synthesis of 2-deoxy-2-iodo glycosides

Copper(II) triflate catalyzed stereoselective glycosylation of 2-iodo-glycosyl acetate donor is reported. Anomeric activation of 2-deoxy-1-O-acetyl sugar employing Cu(OTf)2 found to be an attractive as well effective alternative reagent to the most frequently used triflic acid (TfOH) source such as TMSOTf or TBSOTf. Scope of the reaction was explored for various aglycones. This protocol involves simple reaction operation, employs less expensive and non-toxic reagent system, and enables the stereoselective preparation of 2-deoxy-2-iodo-glycosides. Furthermore, CuI/NaIO4 in the presence of AcOH at ambient temperature promoted the regioselective iodoacetoxylation of various glycals to access 2-iodo-glycosyl acetates.