The original Fischer glycal synthesis was the reductive elimination with zinc of a glycosyl halide. This glycosyl halide was formed from a monosaccharide starting material. Some other synthetic routes include:
*Ring-closing metathesis 
*Reaction of thioglycosides with lithium napthalenide.
*Mesylation of the anomeric hydroxyl and formation of the anomeric palladium complex, which undergoes beta-elimination
A general example of each synthetic route is given below (drawn with first discussed synthesis bottom right, moving clockwise):