Synthesis of 21-oxoporphyrin building blocks and energy donor appended systems

A series of 21-oxoporphyrin building blocks bearing iodo- and ethynyl functional groups were synthesized and characterized. A boron–dipyrrin unit appended 21-oxoporphyrin was constructed using the building blocks under mild palladium coupling conditions which exhibited efficient energy transfer from boron–dipyrrin to 21-oxoporphyrin.