Novel preparation of 2,5-diarylpyrroles from aromatic nitriles with 3-arylpropylmagnesium bromides, 1,3-diiodo-5,5-dimethylhydantoin, and tBuOK

Treatment of aromatic nitriles with 3-arylpropylmagnesium bromides under warming conditions and then water, followed by the reaction with DIH at room temperature under irradiation with a LED lamp and then with tBuOK gave 2,5-diarylpyrroles in moderate yields. The key step of the present method is the formation of N-iodo-2,5-diaryl-4,5-dihydropyrroles by the reaction of the formed imines with DIH, which proceeds through the 1,5-H shift of iminyl radical, 5-exo-tet cyclization by the imine group, and N-iodination of the formed 2,5-diaryldihydropyrroles. © 2022 Elsevier Science. All rights reserved.