Synthesis of pyrrolidine-fused [34]- and [36]octaphyrins via 1,3-dipolar cycloaddition

The utility of expanded porphyrins as a dipolarophile in cycloaddition reactions has been investigated. The 1,3-dipolar cycloaddition of mesooctakis(pentafluorophenyl)[36]octaphyrin(1.1.1.1.1.1.1.1) with an azomethine ylide provides mono- and bis-pyrrolidine-fused octaphyrins regio- and stereoselectively. Treatment of the cycloadduct with MnO2 afforded [34]octaphyrin quantitatively.