Functionalization of β-Alkylcorrole Using Ag(I) Salts

To date, the coordination chemistry of β-alkylcorroles is significantly less developed than that of their triaryl analogues. To address this gap, we investigated the seemingly straightforward synthesis of silver complexes of β-alkylcorroles, employing a procedure previously reported for Ag(III) insertion into meso-triarylcorroles. However, when AgOAc was used as the silver source in pyridine, the reaction resulted in the formation of oxidation products, specifically oxocorroles. In acetonitrile, a broader distribution of products was observed, yielding compounds in addition to oxocorroles. Characterization through UV-vis spectroscopy, 1H NMR, mass spectrometry, and single-crystal X-ray crystallography revealed the formation of an acetate-functionalized oxocorrole, along with a second species resulting from simultaneous silver insertion and acetate incorporation at the meso-position. Substituting AgOAc with AgNO2 demonstrated a marked time dependence: rapid and complete meso nitration occurred within minutes, while extended reaction times also facilitated silver insertion into the preformed trinitrocorrole free base. The use of silver salts with non-nucleophilic anions (e.g., AgPF6 and AgNO3) did not yield either metalation or meso-functionalization. These results suggest that the coordination of the silver ion into the corrole core is almost permitted only after peripheral substitution, highlighting the distinct reactivity of alkylcorroles compared to their triaryl counterparts.