Intermolecular ‘oxidative’ aromatic substitution reactions of the imidazol-5-yl radical mediated by the ‘reductant’ Bu3SnH

The reactivity of the imidazol-5-yl in comparison to the imidazol-2-yl and phenyl radical under the reductive conditions of Bu3SnH, in intermolecular substitution reactions onto various aromatic substrates is reported. The directing effect of the hetero atom or methyl substituent in aromatic substrates was found to be more important than the polarity of the attacking σ-radical in determining the major product isomer.