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

Abstract

Preparation of diverse meso-functionalized porphyrins involves iodine(III)- and copper triflate-promoted dehydrogenative coupling of meso-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.