Stepwise Preparation of meso-Tetraphenyl- and meso-Tetrakis(4-trifluoromethylphenyl)bacteriodilactones and their Zinc(II) and Palladium(II) Complexes

Abstract

While the direct, one-step conversion of meso-tetrakis(pentafluorophenyl)porphyrin to its corresponding bacteriodilactone is well established, no such reaction has been achieved for meso-tetraphenyl or meso-tetrakis(4-trifluoromethylphenyl)porphyrin. Thus, we describe two stepwise oxidation approaches of these porphyrins toward the corresponding bacteriodilactones, as mixtures of two inseparable regioisomers. As shown by 1H NMR spectroscopy, the ratio of the two isomers is oxidant-dependent. Their ZnII and PdII complexes were formed by metal ion insertion into the free bases. Some of the free base dilactones and their metal complexes were also characterized crystallographically, demonstrating the planarity of the macrocycle. This report makes these intriguing porphyrinoids synthetically accessible for further study.