Reductive demetalation of copper corroles: first simple route to free-base beta-octabromocorroles

Although the chemistry of corroles has grown spectacularly in recent years, the field has been marred by the lack of convenient protocols for demetalation of metallocorroles. Reported herein is a superior procedure for demetalating copper corroles with concentrated H2SO4 and 5-200 equiv FeCl2 or SnCl2. The yields obtained with this reductive procedure are generally substantially better than with CHCl3/H2SO4, CH2Cl2/H2SO4, or H2SO4 alone. With an oxidation-prone metallo-corrole such as Cu[T(p-OMeP)C], the reductive protocol was essential for obtaining any measurable yield of the free base at all. Free-base beta-octabromo-meso-triarylcorroles were also obtained in pure form, in good yields, and with relative ease via this procedure. Copyright (c) 2008 Society of Porphyrins & Phthalocyanines.