Quantitative investigation of the ozonolysis reaction. IX. On the mechanism of ozonide formation

Abstract

The ozonide cis-trans ratios, for both normal and cross-ozonides, have been examined, in a number of cases, in pentane and in benzene solutions. In benzene, at 25 "C, almost invariant cis-trails ratios are observed, regardless of the geometry and initial concentration of olefin. In pentane, these ratios have been found to depend, both at -78 and 25 "C, on the geometry and the initial concentration of the olefin when 1,2-disubstituted ethylenes with bulky substituents are ozonized. However, the crossozonide cis-trmu ratios obtained from trisubstituted ethylenes do not depend on the initial olefin concentration. A tentative mechanistic proposal is suggested in terms of transitory zwitterion-oletin adducts.

Oxygen-18 tracer use in ozonolysis mechanism studies. Results using the triphenylphosphine reduction method

“…Solid material was removed from the reaction mixture by suction filtration through a sintered glass Buchner funnel and was washed with 40 ml of methylene chloride. Solvent was removed from the combined solutions by rotary evaporation to give the crude product as a dark maroon oil, which upon crystallization from 60 ml of anhydrous methanol afforded 4.06 g (70%) of diphenyldiazomethane as long, fine needles, mp [28][29][30] °C (lit.43 mp 35 °C).…”

Etude quantitative des réactions d'ozonolyse. XIII. Sur la structure du zwitterion de Criegee

“…Ce rtsultat est interprttt par Story et al en faveur du mtcanisme, rCsumt dans le schtma 1, propost par ces auteurs (8). Un autre mtcanisme a cependant t t t rtcemment envisagt, capable d'expliquer l'incorporation d'oxygtne aldthydique en position peroxyde dans l'ozonide final (9).…”

Spectrométrie de masse des peroxydes organiques. III. Ozonides des styrènes substitués dans le noyau

“…De plus, la connaissance des fragments ioniques issus des ozonides, en spectromCtrie de masse, permet la comparaison et la discussion, sur une base experimentale, des divers mtcanismes qui ont Ct C proposCs pour la formation des ozonides (2,3). Ainsi, par exemple, il a Ctt montrt (2, 4) que l'ozonolyse, dans le tetrachlorure de carbone et le pentane, des stilbines cis et trans, du P-mCthylstyrene, du styrene, et du triphCnyltthyline, en presence de benzaldkhyde-"0, conduit i une incorporation de l'oxygene aldChydique uniquement en position Cther des ozonides formCs.…”