Synthesis of α-l-Fucose-l-¹⁴ C (6-Deoxy-l-galactose-l-¹⁴ C)

α-l-Fucose-l-¹⁴ C was synthesized in a radiochemical yield of 30 percent. The synthesis involved degradation of nonradioactive l'fuconic acid to 5-deoxy-l-lyxose and synthesis from this of α-l-fucose-l-^l4 C by use of ¹⁴C-labeled cyanide in the cyanohydrin reaction. The resulting epimeric, ¹⁴C-labeled aldonic acids were separated as either the barium or the sodium salts. Both salts of l-fuconic acid crystallize more readily than the corresponding salts of the epimeric 6-deoxy-l-talonic acid. The preparation of barium l-fuconate by the electrolytic oxidation of l-fucose in the presence of barium carbonate and barium bromide is described.