Cyclohepta-1,3,5-triene

Compounds. Part VI. 3.4.5.6-Dibenz-cyclohepta-1.3.5-triene. J. chem. Soc. [London] 1947, 746. 

Taking advantage of the rich chemistry of transition-metal-catalyzed cycloisomerization of 1,6-enynes, the electron-rich, conformationally blocked cyclohepta-1,3, 5-triene has been envisioned as a 6-% nucleophilic component [59]. Thus, cycloisomerization of l-(pent-4-ynyl)cyclohepta-l,3,5-trienes in the presence of catalytic amounts of platinum(II) chloride led to a formal intramolecular [64-2] cycloaddition in good to excellent yields [60]. These reactions are conducted at room temperature in toluene as the solvent. A heteroatom in the tether between the unsaturated subunits is tolerated, although in these cases other catalytic pathways were also observed. A mechanism involving cationic intermediates resulting from the nucleophilic attack of the triene on the metal-alkyne moiety has been proposed (Scheme 8.38). The occurrence of ionic intermediates was supported with... 

Literature values of Ahydf are numerous and accurate. There are about 500 known enthalpies of hydrogenation, many of which have an experimental uncertainty of 1 kJ mol" or less. For example, measurements of Ahyd (cyclohepta-1,3,5-triene) using three different techniques in experiments almost a half-century apart, have an arithmetic mean experimental uncertainty and a range, when corrected for solvent effects and temperature differences, of 1.1 kJ mol". This level of accuracy is important now that advances in computational methods are such that the old standard thermochemical accuracy of I kcal mol" (4.2 kJ mol" ) no longer suffices. 

Daino, Y, Hagiwara, S., Hakushi, X, Inoue, Y, and Tai, A., Photochemistry of cyclohepta-1,3-diene and cyclohepta-1,3,5-triene. Photochemical formation and chemical reactivity of the strained trans-isomer,. Chem. Soc., Perkin Trans. 2, 275-282, 1989. 

C12H14 7-(l-ethyl-prop-2-ynyl)-cyclohepta-1,3,5-triene 130652-39-0... 

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