Oxidative nucleophilic substitution of hydrogen in nitroarenes

Article abstract of DOI:10.1002/chem.19970031217

Carbanions of 2-phenylpropionitrile were found to add to nitroarenes in liquid ammonia to form σ(H) adducts, which were oxidized with KMnO₄ to yield products of oxidative nucleophilic substitution of hydrogen (ONSH) in the position para to the nitro group. Treatment of the carbanion-nitroarene system with methyl iodide at -70°C indicated that the addition proceeds almost to completion. Thus, for the first time, the persistence of σ(H) adducts, formed between free anions and mononitroarenes, has been demonstrated. It was also shown that KMnO₄, oxidizes σ(H) adducts to nitrobenzene faster than it does carbanions. This selective ONSH in the para positions of nitroarenes is a general process. However, some substituents hinder or inhibit the oxidation step.