Ozonolysis of cis- and trans-stilbene in the presence of benzaldehyde-18O

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Triphenylphosphine has been found to reduce "0 labelled ozonides of styrene, stilbene, p-methylstyrene, and triphenylethylene by a very selective attack on the peroxidic oxygen atonls of the ozonides. The presence of an electron withdraning phenyl group attached to a C atoll1 of the ozonide ring enhances the attack on the peroxidic oxygen adjacent to this C atom, \?;hereas the presence of an electron releasing methyl group enhances the attack on the other peroxidic oxqgen atom.La reduction, par la tripl~Cnylphospl~ine, des ozonides ~L I styrene, stilbene, p-methylstyrene et du triphinylethylene, marques par 180 dans la position ether, iuontre que I'attaque a lieu tres selective~nent sur les oxygenes peroxpdiques. Le groupe phenyle, relie a un atome de carbone du noyau ozonique, favorise l'attaque siir l'atome d'oxygene peroxydique voisin a cet atome de carbone. Le groupe niethyle exerce une influence contraire.

“…Thc preparation of the IsO labelled ozonides, and the deter~nination of the " 0 content of the ozonides by mass spectrometry, have been described elsewhere (4)(5)(6).…”

Section: Methodsmentioning

confidence: 99%

“…The preparation of the 180 labelled ozoilides of styrene, stilbene, P-methylstyrene, and triphenylethylene has been described previously (4)(5)(6), and the exclusive location of the oxygen isotope in the ether position has been established (5, 6)' by mass spectrometry.…”

mentioning

confidence: 99%

On the reduction of the ozonides of selected phenylethylenes by triphenylphosphine

Carles¹,

Fliszár²

1969

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“…The experimental basis for this proposal is their reported finding that ozonolysis of several olefins in a large excess of propionaldehyde (l), cyclohexanone (I), or pinacolone (3) resulted in reduction of the initial ozonide (to aldehydes and/or ketones) and Baeyer-Villiger oxidation of the added aldehyde or ketone (to propionic acid, 6-hexanolactone, and t-butyl acetate, from the above three, respectively). Since it had previously been shown that ozonolysis of an olefin in the presence of only 1 mol of added aldehyde gave cross ozonides (4,5 ) and since the earlier Story-Murray mechanism (4) accounts for this via attack of the aldehyde on a 1,2,3-trioxolane (e.g. 2) intermediate, Story (2,3) felt that some other species, a precursor to the trioxolane and/or ozonolysis products, was the oxidant which was reduced by the excess aldehyde or ketone.…”

mentioning

confidence: 99%

Mechanism of Ozonolysis. The Initial Ozonide. Lack of Evidence for "Unified Concept" Involving Staudinger Molozonide

Bailey¹,

Thomas²,

Fischer³

et al. 1973

Contrary to previous reports cyclohexanone and pinacolone are not oxidized to the corresponding Baeyer–Villiger oxidation products during ozonolysis of ethylidenecyclohexane in their presence. Addition of propionaldehyde to a solution of the 1,2,3-trioxolane initial ozonide of trans-1,2-di-t-butylethylene resulted in oxidation of the aldehyde to propionic acid and reduction of the 1,2,3-trioxolane to pivaldehyde. Thus, there is no necessity for the four-membered Staudinger molozonide as an ozonolysis intermediate, as recently proposed by Story.

“…To explain different cis-trans ozonide ratios in cross ozonides from cis and trans olefins, a mechanism has been proposed involving a carbonyl -primary ozoilide interaction step (3). Recently, refinements have been added to the Criegee n~echanisrn by advocating the formation of syn and arzti zwitterions which combine stereospecifically with aldehydes or ketones io yield ozonides (4).Two schoois have studled ozonide r i~~g formation using isotopic oxygen (36,5,6). Incorporation of the label nil both the ether and peroxid~c oxygens or aliphatic ozo~iides was interpreted to mean simultaneous operation of the Criegee mechanism and a regenerative carbonyl -primary ozonide interaction as shown :…”

mentioning

confidence: 99%

“…Two schoois have studled ozonide r i~~g formation using isotopic oxygen (36,5,6). Incorporation of the label nil both the ether and peroxid~c oxygens or aliphatic ozo~iides was interpreted to mean simultaneous operation of the Criegee mechanism and a regenerative carbonyl -primary ozonide interaction as shown :…”

mentioning

confidence: 99%

Reactions of ozonides. VIII. An examination of the possibility of reversible ozonide formation using ¹⁴C labelling

Kerur¹,

Diaper²

1969

Carboxyl-14G-10-formyldecanoic acid was made by 14C02 carbonation of 10-undecenylmagnesium bromide and ozonolysis of the product. Attempts were made to equilibrate its methyl ester with CHz / \ @R(CM2)gCOOMe and CH2 GH(CH2)8COOMe in various solvents. Little in-'0-0' corporation of label in the re-isolated ozonide was found, and it was concluded that under normal ozonolysis conditions the formation of ring ozonide is essentially irreversible. Slight incorporation in chloroform is explicable either by reversal of the Criegee n~echanism of ozonide formation or by reversal of the recently suggested regenerative carbonyl -primary ozonide reactions.Canadian Journal of Chemistry, 47, 43 (1969) A recent interest in the mechanism of formation of ozonides from oiefins has been sparled by a close examillation of the stereochemistry of the reaction. The Criegee mechanism (I) accommodates stereospecificity by invoking a solvent cage which must be penetrated in crossozonide formation (2). To explain different cis-trans ozonide ratios in cross ozonides from cis and trans olefins, a mechanism has been proposed involving a carbonyl -primary ozoilide interaction step (3). Recently, refinements have been added to the Criegee n~echanisrn by advocating the formation of syn and arzti zwitterions which combine stereospecifically with aldehydes or ketones io yield ozonides (4).Two schoois have studled ozonide r i~~g formation using isotopic oxygen (36,5,6). Incorporation of the label nil both the ether and peroxid~c oxygens or aliphatic ozo~iides was interpreted to mean simultaneous operation of the Criegee mechanism and a regenerative carbonyl -primary ozonide interaction as shown :In the aromatic 180 study, peroxide irtcorporatlon was very nearly negligible and the label it was pointed out that the same seven-membered appeared in the ether oxygen. This silpports the intermediate can give ether-labelled ozonide by Criegee mechanism, but does not exciude a C-O fi$sion of the primary ozonide as shown interactions of the type shown above, because below rather than 0-0 fission as shown above:Can. J. Chem. Downloaded from www.nrcresearchpress.com by 34.217.195.47 on 05/12/18For personal use only.