- An Experimental Approach to the C8H10 Hypersurface. Kinetic and Thermochemical Investigations on a Formally Forbidden Ground-state <2? + 2?) Cycloaddition
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The C8H10 hydrocarbons 1, 3, 4, and 6 have been thermolyzed in a static system and the Arrhenius parameters have been obtained.Calorimetric measurements have been carried out to determine the heats of formation.From these data an experimental energy hypersurface is constructed which shows the following remarkable features: 1) The ground-state energy of endo-1 is higher than that of exo-4 by 8 kcal/mol. 2) The predominant reaction pathway of endo-1 is the formally forbidden 6 and 4->3 are the same, the reaction yielding 6 is faster due to a sizeably higher A factor. 4) The tetracycle 3 chooses the microscopic reverse pathway, i.e. its thermolysis proceeds via exo-4 to give the diene 6.
- Hassenrueck, Karin,Martin, Hans-Dieter,Mayer, Bernhard,Urbanek, Thomas,Zirwes, Thomas,et al.
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p. 177 - 186
(2007/10/02)
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- Chemistry of 2-Carbenabicyclooctadiene
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Pyrolytic decomposition of the lithium or potassium salt of the tosylhydrazone of bicycloocta-3,6-dien-2-one (11) or photolysis of the lithium salt of 11 results in the formation of bicycloocta-2,6-diene (12), tricyclo2,7>oct-3-ene (13), tetracyclo2,8.04,6>octane (14), semibullvalene (15), 5-ethynyl-1,3-cyclohexadiene (16), and endo-6-ethynylbicyclohex-2-ene (17).The formation of the C8H8 fraction (15-17) is ascribed to insertion and rearrangement reactions of singlet 2-carbenabicyclooctadiene, whereas the formation ofthe C8H10 fraction (12-14) appears to be the result of hydrogen abstraction reactions of the corresponding triplet carbene or closely related species.
- Freeman, Peter K.,Swenson, Karl E.
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p. 2033 - 2039
(2007/10/02)
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