The reaction of 1,2-O-isopropylidene-3-O-propyl-alpha-D-glucofuranose (I) with 4-chlorobenzyl chloride (II) by means of KOH in hot dioxane gives 1',2-O-iso-propylidene-3-O-propyl-5,6-di-O-(4-chlorobenzyl)-alpha-D-glucofuranose (III), which is then hydrolyzed with ethanolic HCl.