On the Mechanism of Reductive Cleavage of the Carbon-Nitrogen Bond of Aliphatic Nitro Compounds with Tributyltin Hydride

Article abstract of DOI:10.1246/bcsj.61.3629

Denitrohydrogenation reaction of aliphatic nitro compounds with tributyltin hydride (Bu3SnH) is accelerated in the presence of radical initiators.ESR and electrochemical measurements reveal that the reductive cleavage of the carbon-nitrogen bond proceeds not via anion radicals of nitro compounds such as S_RN1 reaction but via β-scission of (tributylstannyloxy)nitroxyl radicals.The relative reactivities of tin radicals toward substituted α-nitrocumenes, α-nitroethylbenzenes, and α-nitropropiophenones exhibits excellent Hammett correlations with positive ρ values.This tendency has also been found in the reaction of benzyl halides with tin radical.These results suggest that the carbon-nitrogen bond breaking from nitroxyl radical intermediates should take place in rate-determining step for the reaction.