An efficient and convenient method for the synthesis of 2-deoxy-2-iodo-O-glycosides from tri-O-acetyl-D-glucal with various alcohols by using I(2)-Cu(OAc)(2) is described. The 21 examples of corresponding glycosides were obtained in high yields, with good anomeric selectivity.
The observation of convertible formation between 2-deoxy-2-iodo-O-glycosides and 2,3-unsaturated glycoside was described. The selective formation of 2-deoxy-2-iodo-O-glycosides was found from the reaction of D-glucal with iodine in the excess alcohol acceptor or the addition of ceric ammonium nitrate as additive while the addition of a stoichiometric amount of alcohol in solvent favored 2,3-unsaturated glycosides formation.