Direct arylation of meso-formyl porphyrin.

Palladium-catalyzed direct arylation of meso-formyl Ni(II) porphyrin with aryl bromides provided β-monoarylated meso-formyl porphyrins. In spite of the existence of the meso-formyl group, the reactions proceeded regioselectively at the β-position adjacent to the formyl group. β-Arylated formyl porphyrin was converted to a tetraline-fused porphyrin by reduction and subsequent acid-catalyzed cyclization and to a meso-meso vinylene-bridged diporphyrin by McMurry coupling (see scheme).