"Ambident Reactivity of the Nitrite Ion Revisited"A. A. Tishkov, U. Schmidhammer, S. Roth, E. Riedle, and H. Mayr
Angewandte Chemie, Int. Ed. 44, 4623-4626 (2005)
The rationalization of the ambident reactivity of NO2- by the Salem-Klopman model has to be revised. In SN1 type reactions carbocations give kinetically controlled product mixtures only when these reactions proceed without activation energy (diffusion control). Activation controlled SN1 alkylations are reversible and lead to the formation of the thermodynamically more stable nitro compounds. The regioselectivities of methylations of the nitrite ion (SN2) are almost independent of the hardness of the methylation agent.
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