Synthesis of 8,12-Dibromocorrole and Its Transformation to Antiaromatic 8,10-Fused Iminoisocorrole with a Polarized Resonance Contribution

8,12-Dibromo-5,15-bis(pentafluorophenyl)corrole and its Ag(III) complex were prepared via intramolecular oxidative coupling of a 8,12-dibromobilane precursor. The Ag(III) complex was allowed for further transformation via Suzuki coupling reaction. Thus, 2-aminophenyl group was coupled at one of the beta-positions, and subsequent demetalation followed by oxidation with MnO2 afforded 8,10-fused iminoisocorrole in good yields. The iminoisocorrole exhibited weak antiaromaticity due to the C(+)-N(-) polarized resonance contribution as evidenced by H-1 NMR spectrum, UV/vis absorption spectra, cyclic voltammetry, and theoretical calculations.

Automated summary

The 8,12-Dibromo-5,15-bis(pentafluorophenyl)corrole and its Ag(III) complex were prepared through intramolecular oxidative coupling, and further transformed via Suzuki coupling reaction to yield the 8,10-fused iminoisocorrole. The iminoisocorrole exhibited weak antiaromaticity due to the C(+)-N(-) polarized resonance contribution, as confirmed by various spectroscopic techniques and theoretical calculations.