Oxidation of 2-methylpyrroles with perchlorinated iron(III) metalloporphyrin catalysts: a versatile synthesis of symmetric and asymmetric dipyrromethanes

A variety of substituted 2-methylpyrroles (3-8) were oxidized using the met alloporphyrin catalysts iron(III) meso-tetra(2, 6-dichloro-3-sulphonatophen yl)-beta-octachloroporphyrin chloride 1 and iron(III) meso-tetra(2,6-dichlo rophenyl)-beta-octachloroporphyrin chloride 2 under very mild conditions. T reatment of the resulting allylic alcohols 3a-8a with alpha-free pyrroles 9 and 10 resulted in a very efficient synthesis of the corresponding dipyrro methanes 3b-8b and 3c-8c. Furthermore, the above allylic alcohols when trea ted with furfurylamine produced the novel (2-furylmethyl)-2-pyrrolylmethyla mines 3d-8d.