77884-76-5Relevant academic research and scientific papers
REACTIONS OF CYCLO-OCTATETRAENE AND ITS DERIVATIVES-IX. CYCLOPENTADIENONE ADDUCTS OF TRICYCLO2,5>DECA-3,7-DIENES AND TRICYCLO2,5>NONA-3,7-DIENES
Akhtar, Iqbal A.,Atkins, Richard J.,Fray, Gordon I.,Geen Graham R.,King, Trevor J.
, p. 3033 - 3042 (2007/10/02)
Tetracyclo2,9.03,8>tetradeca-4,6,11-trienes 5 are produced from tricyclo2,5>deca-3,7-dienes 1 by reaction with cyclopentadienones 2 (or equiv) followed by thermal decarbonylation.With tetraphenylcyclopentadienone, however, the product 5e rearranges under the conditions required for its formation to give the dihydrosemibullvalene 11.The rearrangement evidently proceeds via the cyclo-octa-1,3,5-triene 14, the ring-opening 5e-14 being facilitated by a phenyl-conjugation effect, uncovered in another series of experiments involving the reaction of cyclopentadienone s with the tricyclo2,5>nona-3,7-diene 16.Thus the tetraphenylcyclohexa-1,3-diene 18c undergoes ring-opening in refluxing xylene to afford the cyclo-octa-1,3,5-triene 21a, whereas the dimethyldiphenyl-analogue 18b resists valence isomerisation under these conditions.
PERICYCLIC TRANSFORMATIONS OF TETRACYCLO2,903,8>TRIDECA-4,6,11-TRIENES, AND FORMATION OF DIHYDROSEMIBULLVALENES BY THERMAL INTRAMOLECULAR?4a+?2a>CYCLOADDITION IN SUBSTITUTED CYCLOOCTATRIENES
Lay, W. P.,Mackenzie, K.,Miller, A. S.,Williams-Smith, D. L.
, p. 3021 - 3031 (2007/10/02)
Cyclopentadienones react with certain cyclobutene dienophiles to give the anticipated carbonyl bridge adducts; these, on relatively mild thermolysis, yield dihydrosemibullvalene derivatives by a novel sequence including cheletropic loss of carbon monoxide, electrocyclic ring opening of immediate substituted bicyclooctadienes, and intramolecular ?4a + ?2a>cycloaddition of the derived cyclooctatrienes.Other pericyclic reactions of compounds related to those of the title compounds are also discussed.
