The Chemistry of Pyrrolic Compounds. LXIII. Synthetic Studies of Petroporphyrins With Fused Six-Membered Ring Systems

Abstract

Several approaches to the synthesis of porphyrins bearing fused six- membered ring systems were explored with the aim of obtaining the petroporphyrin (4a). This was ultimately achieved by an intramolecular cyclization of a porphyrin with a propanoyl chloride side chain in the presence of stannic chloride. Methylation of the intermediate ketone with CH₃Li and reduction of the resultant alcohol with NaBH₃CN/Znl₂ furnished (4a).