An easy synthetic approach to pyridoporphyrins by domino reactions

beta-Amino-meso-tetraarylporphyrins react with cyclic enol ethers to yield pyrido[2,3-b]porphyrins bearing two vicinal hydroxyalkyl groups. These reactions are catalyzed by lanthanum triflate and occur under mild conditions. Esterification of the hydroxyalkyl groups with succinic anhydride and dodecanoyl chloride afforded the corresponding esters in almost quantitative yields. The crystal structure of the most hydrophobic derivative 7 was determined, and it shows that these porphyrinic macrocycles form one-dimensional supramolecular tapes in the solid state.