A new deoxygenation of kanamycin A leading to 3', 4'-dideoxykanamycin A and 4'-deoxykanamycin A is described. The key stage in the syntheses involves the formation of the 3', 4'-anhydro-4'-epi derivative (5) followed by its conversion to the 3'Δ and 4'-deoxy derivative through the iodohydrin. Compound 5 was prepared by the treatment of 2', 3', 2"-tri-O-benzoyl-4", 6"-O-cyclohexylidene-4'-O-methylsulfonyl-tetra-N-tert-butyloxycar-bonylkanamycin A (4) with sodium methoxide.