Synthesis of N-Heterocycle-Ligated Porphyrins Using Iodobenzene Diacetate Enabled Regioselective Cross-Dehydrogenation of Porphyrins and NH-Heteroaromatics

Preparation of diverse <i>meso</i>-functionalized porphyrins involves iodine(III)- and copper triflate-promoted dehydrogenative coupling of <i>meso</i>-free porphyrins and appropriate NH-free heterocycles. Reaction conditions involving the stable and recyclable iodobenzene diacetate reagent are compatible with a range of NH-free heterocycles (acridone, phenoxazine and phenothiazine, carbazole, β-carbolin triazoles, imidazole, pyrazole, indazole, and tetrazole) and porphyrins to access diversely functionalized A₃B, A₂BC, and A₂B₂ porphyrins in moderate to good yields. The prepared heterocycle-appended porphyrins exhibit modestly red-shifted Soret and Q bands in the absorption spectra.