The Application of Hangman Fe(IV) Corrole in the Baeyer-Villiger Oxidation Reaction

A series of new hangman iron corroles with different electronic structure and pending aldehyde group were prepared and used as catalyst in Baeyer-Villiger (B-V) oxidation reactions. The results show that hangman iron corroles exhibit faster reaction rates and higher epsilon-caprolactone yields as compared to triaryl iron 5,10,15-tri(pentafluorophenyl) corrole (Fe(tpfc)Cl). With the increase in the electron-withdrawing ability of the meso-position substituents of hangman iron corrole, the yield of caprolactone also increases. Under optimal conditions, the best hangman iron corrole bearing two pentafluorophenyl groups (FePXC) may give a yield of 97% at only 0.07 mol% catalyst loading. The turnover number (TON) of the FePXC catalyst could be up to 2100 in a gram-scale test of oxidation of cyclohexanone. This work demonstrates the good potential of hangman corroles in B-V oxidation.