Regioselective halogenation and palladium-catalysed couplings on 5,15-diphenylporphyrin

5,15-Diphenylporphyrin was regiospecifically halogenated in high yield to g ive 5-iodo-15-bromo-10.20-diphenylporphyrin, which was then subjected to He ck and Stille-type coupling reactions to form unsymmetrically substituted p orphyrins. The regioselectivity of the iodination of diphenylporphyrins and subsequent formation of amphiphilic porphyrins via palladium-based methodo logy was also studied. The utility of this method for the synthesis of phot odynamic sensitisers has been demonstrated on AR4-2J rat pancreatic carcino ma cells. Copyright (C) 2000 John Wiley & Sons, Ltd.