trans-2-Cycloheptenone¹

Interpretation of Some Organic Photochemistry

“…The even more strained trans-2-cycloheptenone is formed on irradiation of the cis-isomer at low temperature (26,27). The even more strained trans-2-cycloheptenone is formed on irradiation of the cis-isomer at low temperature (26,27).…”

Ultra‐fast Laser Spectroscopy of Visual Pigments

“…That the rhodopsin analog having a 7-membered retinal displayed a CD spectrum similar to that of rhodopsin (Akita et al, 1980), while that having a 5-membered retinal has a negligible CD at the aband (Fukada et al, 1984) supports these aspects. Furthermore, there have been several reports that cis-trans photoisomerization from a cis configuration fixed by a 6-or 7-membered ring to a highly twisted trans configuration takes place in a transient state (Bonneau et al, 1976;Dauben et al, 1979;Corey et al, 1965;Eaton and Lin 1965;Liu, 1967;Inoue et al, 1985). Therefore, it is reasonable to speculate that the photochemical reaction of 5-membered rhodopsin should be different from that of 7-membered rhodopsin.…”

Photoannelation Reactions of 3‐(Alk‐1‐ynyl)cyclohept‐2‐en‐1‐ones

“…This is most probably due to the fact that the more flexible cyclohept-2-enones a) undergo efficient (Z) ! (E) photoisomerization [3] [4], and b) exhibit lower E T values than the corresponding smaller cycloenones. The only established cyclobutane forming reaction of cyclohept-2-enones is photodimerization to afford tricyclo[7.5.0.0 2,8 ]tetradecanediones.…”