Regioselective [3+4] cycloaddition of an azomethine ylide to meso–meso, β–β, β′–β′ triply linked diporphyrins

Thermal reaction of meso–meso, β–β, β′–β′ triply linked diporphyrins with an azomethine ylide produced seven-membered cycloadducts via formal [3+4] cycloaddition at the bay-area. Bischlorin structures of the cycloadducts are characterized on the basis of spectroscopic data and confirmed by single crystal X-ray diffraction analysis. Interestingly, the stability of the cycloadducts depends on the central metal ions in the porphyrin core.