Nitrogen dioxide reactions with alkenes

Much evidence has been accumulated that the ozone-olefin reaction has a predominant role in aerosol formation from alkenes, cyclic olefins, diolefins, and other unsaturated compounds. Free radicals are formed in the reaction and can react further, along with nitric oxide and nitrogen dioxide, either with the various intermediates or with the olefin itself (see the recent review by Pitts and Finlayson ). 

Pokholok T. V., Pariiskii G. B. Formation of spin-labeled maeromoleeules in reactions of elastomers with nitrogen dioxide. Polymer Science, Ser A 1997 39 (7) 765-71. Giamalva D. H., Kenion G. B., Chureh D. F., Pryor W. A. Rates and mechanisms of reactionof nitrogen dioxide with alkenes in solution. J. Am. Chem. Soc. 1987 (109) 7059-63. 

Park J. S. B., Walton J. C. Reactions of nitric oxide and nitrogen dioxide with functionalised alkenes and dienes. J. Chem. Soc., Perkin Trans. 2 1997 2579-83. 

The reaction is akin to the Ritter reaction, with activation achieved by nitration, rather than proton-ation, and the products accordingly retain the nitro group. Additions to 1-phenylcyclohexene (59%) and to franr-stilbene (72%) are stereospecific (trans) cfr-stilbene gives the expected tfireo product (39%) plus some erythro (6%). Reactions of nitrogen dioxide with alkenes are very complex and rarely use-ful. A recent mechanistic paper gives many key references. " Addition of NjOs is occasionally usefiil, as with dicyclopentadiene (Scheme 49). ... 

The reaction of alkenes with nitric oxide (NO), a mixture of nitric oxide and oxygen, or dinitrogen trioxide leads to /i-nitroso nitro compounds ( / -nitrosites or pseudo-nitrosites), which can convert to nitroso dimers79. Nitroalkenes are common byproducts in these reactions. The formation of /i-nitroso nitro compounds in the reaction between alkenes and nitric oxide is explained by the presence of nitrogen dioxide and dinitrogen trioxide in the nitric oxide. The reaction may be initiated by the attack of the N02 radical on the alkene to give a /i-nitroalkyl radical which then couples with nitric oxide. 

The reactivity of alkanes and cycloalkanes are very low. Alkenes and alkynes containing double and triple bonds are reactive. The addition reactions follow Markovnikov rule. Conjugated dienes undergo Diels-Alder reactions. The substances that may react violently with unsaturated hydrocarbons are halogens, strong oxidizers, and nitrogen dioxide. Alkynes may form acetylides with certain metals. 

Some of the possible ways in which sulphur dioxide may react in the atmosphere are as follows (1) photochemical reactions, (2) photochemical and chemical reactions in the presence of nitrogen oxides and/or hydrocarbons, particularly alkenes (olefins), (3) chemical processes in water droplets, particularly those containing metal salts and ammonia, and (4) reactions on solid particles in the atmosphere. Bearing in mind that the atmosphere is a highly dynamic system with great variations in temperature, composition, humidity, and intensity of sunlight it is understandable that different processes may predominate under various atmospheric conditions. 

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