The capacity of an α-nitroalkyl radical for hydrogen abstraction

Photochemical decomposition of 2-iodo-2-nitroadamantane in several hydrogen donating solvents, gives rise to formation of α-nitroalkyl radicals. Such ambident radicals can abstract hydrogen from the solvent via oxygen, resulting in a nitronic acid which decomposes exlusively into adamantanone. Alternately the abstraction can take place via carbon to give 2-nitroadamantane. The product distribution is strongly influenced by electron-withdrawing substituents in the hydrogen donor. The oxidation products derived from the solvent have been detected. All the experiments point towards a minor stabilisation of a carbon radical by a nitro group. INDO-calculations on the nitromethyl radical are in good agreement with this lack of stabilization.