Fluorination of vinorelbine bitartrate (I) with SbF5 and NBS, NCS, Br2 or Ca(OCl)2 (1), with SbF5 and CCl4 (2, 3) or with SbF5 and CHCl3 (3), all in anhydrous HF, gives directly vinflunine (1). Alternatively, fluorination of vinblastine (II) or 3',4'-anhydrovinblastine (III) with SbF5 and CHCl3, 2,2-dichloropropane, CBr4, BBr3 or CH2Br2 in anhydrous HF yields 4'-deoxy-20',20'-difluorovinblastine (IV), which is submitted to a C'-ring contraction by treatment with trifluoroacetic acid and NBS in CH2Cl2, then neutralization with NaHCO3 and finally hydrolysis in THF/H2O/CH2Cl2, optionally in the presence of AgBF4 (4).