Synthesis of directly fused porphyrin dimers through Fe(OTf)3-mediated oxidative coupling.

An efficient and general Fe(OTf)3-mediated oxidative coupling method was developed for the synthesis of doubly or triply linked porphyrin dimers. Besides the central metal and peripheral substituent, regioselectivity of the oxidative coupling was found to be closely relevant to the onset oxidation potential of the porphyrin substrate, and the reactant with higher E(onset(ox)) tends to generate meso-β doubly fused porphyrin dimer.