A simple and efficient method to label l-fucose

This letter reports a new labeling method of fucoidan and more precisely of its monomer, l-fucose. We studied the coupling processes of new aryliodide precursors to l-fucose in order to prepare the next step, that is, the fucoidan radiolabeling. The use of precursors containing hydrazide and hydroxylamines is an alternative procedure avoiding the use of toxic borohydride or organic borane used for reductive amination. These coupling reactions are efficient and stereoselective. They provide stable products.