Cycloheptatetraene and Its Simple Derivatives

Chapman et al. [229] observed the IR spectrum of 10 in an argon matrix at -258 °C in 1988. Photolysing (7 470 nm) p-tolyldiazomethane, they generated the respective triplet carbene, which was converted to 10 on further irradiation (7 416 nm). Analogously, from m-tolyldiazomethane, a mixture of 10 and 4-methyl- 

The results of the gas-phase pyrolysis of the sodium salts of 2- and 4-methyltro- 

Diphenylcarbene also undergoes a ring expansion of the above kind. When it was generated in the gas phase at 350°C/3Torr, small quantities of tetraphenylethylene, the triphenylheptafulvene 563 and the diphenylheptafulvalene 564 were formed in addition to fluorene (565), which was obtained in 29% yield. As illustrated in 

Dimers with a 1,2-bismethylenecyclobutane structure were obtained from 585 [240], 590 [238], 591 [241], 592 [242], 593 [243] and from the pinene derivative 597 [244]. The interception of 592 by 1,3-diphenylisobenzofuran (DPIBF) afforded two diastereomeric [4+ 2]-cycloadducts [245], Bicyclo[5.1.0]octa-3,4-diene (594) was generated by /3-elimination and trapped by sodium pyrrolidide because of the question of the extent to which the corresponding bicyclooctyne is formed in addition to 594 [184], Liberated by /3-elimination from ll,ll-dichloro-l,6-methano[10]annulene in 

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