Evidence from15N nuclear polarization on the mechanism of addition of nitrogen dioxide to alkenes

Abstract

Nitrogen dioxide reacts with 2-ethyl-1-butene and 2-methyl-2-pentene in n-hexane as solvent to give mainly the corresponding dinitro compounds and nitro alcohols (believed to be derived from nitronitrites during the separation process). When 15N-labelled nitrogen dioxide is used, the products show strong 15N nuclear polarization: the signal from the first nitro group to be introduced into the alkene shows enhanced absorption and, in the dinitro compounds, the signal from the second nitro group is in emission. The results indicate that both the dinitro compounds and the nitronitrites are formed by the reaction of the alkenes with two successive nitrogen dioxide molecules. The results do not, however, exclude the possible contributions of other reaction paths.

Side-Chain Nitration of Styrene and Para-Substituted Derivatives with a Combination of Nitrogen Dioxide and Ozone

“…The reversible nature of this addition reaction has been confirmed by 1 H-NMR monitoring using 2,3-dimethyl-2-butene as a substrate and benzene, ether, or n -hexane as the solvent . The mechanism of the addition of nitrogen dioxide to alkenes has been studied extensively by kinetic , and spectroscopic means , path a ) .…”

“…The mechanism of the addition of nitrogen dioxide to alkenes has been studied extensively by kinetic , and spectroscopic means , path a ) . However, different modes of addition may also be operative under certain conditions, since the kinetic order of the reaction becomes higher in [NO 2 ].…”

Nitration of styrenes by dinitrogen pentoxide in dichloromethane

“…The addition of NO, to alkenes has been suggested to occur in this way and it has been shown that the observations are in accord with Kaptein's rules. 5 The radical route to 1 can be explained similarly, because the second addition of the NO, can occur through the oxygen to generate nitrite or the nitrogen. The p-nitro nitrite was not observed but would be expected to be oxidised rapidly to the p-nitro nitrate under the conditions.…”