Alkenes nitrous oxide

The oxidation of alkenes by nitrous oxide on silver at 350°C has been studied from the viewpoint of structure effects on rate by Belousov, Mulik, and Rubanik (J40), and very good correlations of Type B have been found with ionization potentials and with the rate of oxidation by atomic oxygen (series 110 and 111). 

Nitroso compounds are formed during the addition of nitrous oxide," " dinitrogen trioxide, and nitrosyl halides to alkenes, and in some cases, from incomplete oxidation of amines with peroxyacids like peroxyacetic acid. Quenching of carbanions with nitrosyl halides is also a route to nitroso compounds. A full discussion on this subject is beyond the scope of this work and so the readers are directed to the work of Boyer. ... 

Reaction with a cyclic amine in the presence of a base and at ambient temperature forms alkene. Thus, nitrosyl chloride reacts with aziridine to form ethylene and nitrous oxide ... 

Studies in this field are just beginning, and the number of publications hardly exceeds a dozen. The most interesting results were obtained by the research groups of Yamada [160-162], Neumann [163,164] and Kozhevnikov [165, 166], Using various type catalysts (Ru porphyrene complexes, polyoxometalates, supported metals), the authors conducted selective oxidations of various types. These include epoxidation of alkenes, oxidation of alcohols, oxidation of alkylaromatics, oxidation and aromatiza-tion of dihydroanthracenes, and some other reactions. The experiments were typically conducted at 373—423 K under 1.0 MPa pressure of nitrous oxide. 

The ability of nitrous oxide to forma 1,3-dipole (Section 7.2) seems to be of critical importance for the reaction with alkenes. The oxygen transfer proceeds via the 1,3-dipolar cycloaddition mechanism, assuming intermediate formation of a 1,2,3-oxadiazoline complex, the decomposition of which leads to a carbonyl compound ... 

Ben-Daniel, R Weiner, L. and Neumann, R. (2002) Activation of nitrous oxide and selective epoxidation of alkenes catalyzed by the manganese-substituted polyoxometalate, [Mnnl2ZnW... 

The addition of ozone (O3) to alkenes to give a primary ozonide (molozonide), which rearranges to an ozonide and eventually leads, on reduction, to carbonyl compounds (aldehydes and/or ketones), has already been mentioned and the reaction itself is shown in Scheme 6.11. However, it is important to recognize that this is only one example of a 4th- 2n electrocyclic addition and that orbital overlap for many sets of these reactions dictates their courses as well. Thus, to show the similarity of some of these dipolar 3 -f 2 addition reactions Equations 6.53-6.56 are provided. Although any alkene might be used as an example, (Z)-2-butene is used in each to emphasize that aU of them occur with retention of stereochemistry and, in the first (Equation 6.53), the reaction with ozone to form the primary ozonide (molozonide) is presented again (i.e., see Scheme 6.11). In a similar way, with a suitable azide, R-N3, readily prepared from an alkyl halide (Chapter 7), the same alkene forms a triazoline (Equation 6.54) and with nitrous oxide (N2O) the heterocycle (Chapter 13) cis -4,5-dimethyl-A -l,2,3-oxadiazoline (ds-4,5-dihydro-4,5-dimethyl-l,2,3-oxadiazole) (Equation 6.55). Finally, with a nitrile oxide, such as the oxide derived from ethanenitrile (acetonitrile [CH3ON]), the same alkene yields a different heterocycle, the dihydroisoxazole, 3,4,5-trimethyl-4,5-dihydroisoxazole (Equation 6.56). 

Treatment of an aziridine with nitrosyl chloride, S-nitro-TV-nitrosocarbazole or methyl nitrite leads to the formation of an alkene and nitrous oxide (equation 76) " an intermediate iV-nitroso derivative was isolated at low temperatures. The deamination of cis-and frflBJ-2,3-dimethylaziridine gave the corresponding ds- and fra J-2-butenes with complete stereospecificity in each case. The reaction was found to be first order with respect to the A nitroso intermediate and the transition state was suggested to involve simultaneous cleavage of both C—bonds. A similar decomposition... 

Nitrous oxide (N2O) is an interesting oxidant for the selective oxidation of organic substrates since it contains 36 wt. % oxygen, and the by-product of an oxidation reaction is molecular nitrogen. These advantages are difficult to realize since N2O is generally considered to be scarcely reactive. Nevertheless, [Mn ZnW(ZnW9 034)2] catalyzed the selective epoxidation of alkenes under 1 atm N2O in fluo-robenzene at 150°C, with up to 25% yield. 

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