1871-52-9Relevant articles and documents
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Cope,Hochstein
, p. 2515,2519 (1950)
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Nefedov,Agavelyan
, (1971)
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Cope et al.
, p. 4867,4871 (1952)
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Akhtar,I.A.,Fray,G.I.
, p. 2802 - 2804 (1971)
Fragmentation Patterns in the Gas-Phase Pyrolysis of Some Bi- and Tri-cyclic Sulfolanes Related to the 8-Thiabicyclonon-3-ene 8,8-Dioxide Ring System
Aitken, R. Alan,Cadogen, J. I. G.,Gosney, Ian,Newlands, Stephen
, p. 2301 - 2308 (2007/10/02)
Depending upon the degree of ring strain, the thermal breakdown of cis-8-thiabicyclonon-3-ene 8,8-dioxide 5 and related ring systems in the gas phase follows widely differing pathways.Decomposition of 5 occurs only under forcing conditions, resulting in complete fragmentation of the sulfolane ring to give a benzene and toluene, while pyrolysis of the 2,5-bridged analogues 6-8 proceeds by a retro-Diels-Alder reaction at much lower temperatures to give 1,3-dienes and the decomposition products of 3-sulfolene, buta-1,3-diene and SO2.Epoxidation of the double bond in the compounds results in a marked change in their thermal fragmentation behaviour; only SO2 is lost to produce novel divinyl epoxides.The corresponding N-ethoxycarbonylaziridines, formed by photolysis of the unsaturated sulfones in ethyl azidoformate, undergo extensive decomposition on pyrolysis and do not yield any useful products.The saturated sulfone 28 gives an expected octa-1,7-diene upon flash vacuum pyrolysis (FVP), but only under relatively severe conditions.Three isomeric diene sulfones 30-32 have also been examined and show a varied pattern of reactivity under FVP conditions.
STRAINED CYCLOALKENYNES
Meier, Herbert,Hanold, Norbert,Molz, Thomas,Bissinger, Hans Joachim,Kolshorn, Heinz,Zountsas, Johannes
, p. 1711 - 1720 (2007/10/02)
Presently known strained cycloalkynes with one, two or three additional cis- or trans-configurated double bonds are summarized in Table 3.The main topics of the article are the geometrical ring strain, the preparation or in situ generation of these compounds by fragmentation of the corresponding 1,2,3-selendiazoles, and the thermal isomerisation processes performed at room temperature or in flash pyrolysis experiments at 440-640 deg C.