Summary Method of producing a free nucleoside compound by reacting a a glycoside donor preferably a 1-halogen derivative, or 1-0-acyl, 1-o-alkyl, or an imidate preferably a trichloromethyl derivative, or a thio-alkyl derivative of a blocked monosaccharide or oligosaccharide preferably ribose and 2-desoxyribose derivatives with a protected nucleoside base, in a suitable anhydrous solvent and in the presence of a catalyst, and removing the protecting groups from said blocked nucleoside compound, wherein said catalyst is selected from the group comprising salts of an aliphatic sulphonic acid and/or salts of a optionally substituted aromatic sulphonic acid.
