The β-nitration reaction carried out on the corrole macrocycle has been shown to be extremely regioselective, although the reduced symmetry of the macrocycle could potentially lead to a huge number of possible regioisomers. We recently reported that the careful use of AgNO 2/ NaNO 2 as a nitrating system enabled the achievement in good yields of mono- and dinitro-derivatives on both corrole free base and its copper complex, proving to be an efficient and cost-effective method. In this work, we present a detailed study of the scope of this method using TtBuCorrH 3 as a model corrole. A further increase of the oxidant pushes the nitration up to the functionalization of three β-pyrrolic positions, although concomitant decomposition of the macrocycle is also observed. The application of the proven nitration method with a five-fold excess of both silver and sodium nitrites with respect to corrole, afforded the 2,3,17-( NO 2)3- TtBuPCorrCu as the main product, in 25% yield, together with traces of another compound identified by X-ray crystallographic analysis as the 3,8,17-( NO 2)3- TtBuPCorrCu isomer. In light of these recent results, we also reinvestigated the characterization of the nitration products obtained from bis-substitution reactions, allowing among others the identification of the copper 3,8-( NO 2)2 corrolate.
Herein, we report on the mechanochemical reaction of pyrrole and substituted benzaldehyde precursors to produce freebase corroles and demonstrate the one-pot mechanochemical synthesis of 5,10,15-Tris(4-[Formula: see text]-butylphenyl)corrole (H[Formula: see text]-buPhC), in which both, the condensation and oxidation reactions steps, took place in the ball mill. Moreover, we could achieve the mechanochemical synthesis of copper corroles with decent overall yields of 10–12%. With the mechanochemical approach we could shift the EcoScale obtained from common synthesis procedures to significant more positive values and the E-factor for the mechanochemical copper insertion was lowered by factor of 3.0.