Photochemical and oxidative cyclisation of tetraphenylpyrroles

The photochemical and oxidative cyclodehydrogenation reactions of tetraphenylpyrroles act in a complementary fashion for the cyclisation of N -ethyl and N -benzyl derivatives. In the case of the former, a doubly cyclised product was isolated from cyclisation with solid FeCl 3 , while the latter gives a rearranged 3 H -pyrrole upon irradiation. The cyclisation of tetraphenylpyrroles under complementary conditions allows controlled cyclisation giving products dependent on N -substitution, with both tandem rearrangement and halogenation being observed.