Synthesis and chemistry of new benzoporphyrins

M. Graça H. Vicente, University of California, Davis
Laurent Jaquinod, University of California, Davis
Richard G. Khoury, University of California, Davis
Acacia Y. Madrona, University of California, Davis
Kevin M. Smith, University of California, Davis

Abstract

Benzoporphyrins 5 and 6 are the major products obtained from the cycloaddition reactions of β-fused metallopyrroloporphyrins 1 and 2 with dimethyl acetylenedicarboxylate. In the presence of excess dienophile a bis- adduct is also obtained which undergoes retro-Diels-Alder reaction to produce 5. Benzoporphyrin 5 was converted into the first reported β-fused benzochlorins 9-11, and the free-base benzoporphyrin 12 was regioselectively brominated to afford 13. Exhaustive bromination also yields hexabromobenzoporphyrin 14.