PdCl2 (MeCN) 2 in combination with dppp proved to be a powerful and efficient catalyst for the coupling of sterically hindered N-arylsulfonylhydrazones with aryl halides, thus providing a flexible and convergent access to tetrasubstituted olefins related to iso-combretastatin A4 in good yields. This new protocol has been applied successfully to the formal synthesis of biphenylisopropylidene 4-pyridine CYP17 inhibitor, 12b, of biological interest.
