
%0 Journal Article
%A Rye, AR 
%A Wege, D 
%T Preparation and thermolysis of <I>exo</I>-and <I>endo</I>-Tricyclo[6,2,1,0<sup>2,7</sup>] undeca-3,5,9-triene
%J Australian Journal of Chemistry
%D 1974/09/01
%V 27
%N 9
%P 1943-1959
%K 
%R https://doi.org/10.1071/CH9741943
%U https://www.publish.csiro.au/paper/CH9741943 
%X Syntheses of exo- and endo-tricyclo[6,2,1,02,7]undeca-3,5,9-triene, (3) and (4) respectively, are described. Both trienes undergo ready &#960;4s+ &#960;28 cycloreversion to yield cyclopentadiene and benzene at 40-60ºC, the exo-triene (3) being slightly more reactive. At 60ºC, for (3) k = 2.29x 10-3 s-1, &#916;H? = 104.1 ± 4.2kJ mol-1, &#916;S? =14.6 ± 1.6 mol-1 K-1, while for (4) k = 5.25 x 10-3s-1, &#916;H? =ll5.0 ± 3.3 kJ mol-1, &#916;S? = 34.3 ± 13.0 J mol-1 K-1 .  The cycloreversion of (3) and (4) are believed to be concerted reactions. The related dienes exo- and endo-tricyclo[6,2,1,02,7]undeca-3,5-diene, (25) and (28) respectively, have also been prepared, and are stable up to 200ºC. At 300ºC, interconversion between (25) and (28) occurs, apparently via bicyclo[6,2,1]undeca-2,4,6-triene. The relationship of the trienes (3) and (4) to the recently described bicyclo[6,2,l]undeca-2,4,6,9-tetraene is discussed. 
