5259-71-2Relevant articles and documents
Discontinuous pressure effect upon enantiodifferentiating photosensitized isomerization of cyclooctene
Kaneda, Masayuki,Asaoka, Sadayuki,Ikeda, Haruhiko,Mori, Tadashi,Wada, Takehiko,Inoue, Yoshihisa
, p. 1272 - 1273 (2007/10/03)
A hydrostatic pressure of up to 750 MPa induced discontinuous changes in the enantiomeric excess of the (E)-isomer obtained in the enantiodifferentiating photoisomerization of (Z)-cyclooctene and (Z,Z)-cycloocta-1,5-diene, sensitized by chiral benzene-1,2,4,5-tetracarboxylates; indicating a switching of the enantiodifferentiation mechanism, which is attributable to dramatic conformational changes of chiral alkoxycarbonyl auxiliaries at a specific pressure.
Photoelimination of nitrogen from cyclic azo alkanes. An exceptionally labile and an exceptionally reluctant diazabicyclo[2.2.2]octene
Turro, Nicholas J.,Liu, Jonq-Min,Martin, Hans-Dieter,Kunze, Michael
, p. 1299 - 1302 (2007/10/02)
The photochemistry of an unusually reactive diazabicyclo[2.2.2]octene has been found to be extremely solvent and temperature dependent; an exceptionally stable diazabicyclo[2.2.2]octene has been found to undergo a novel fragmentation as a result of vapor phase photoexcitation.
Singlet photosensitization of simple alkenes. Part 2. Photochemical transformation of cyclo-octa-1,5-dienes sensitized by aromatic ester
Goto, Seizi,Takamuku, Setsuo,Sakurai, Hiroshi,Inoue, Yoshihisa,Hakushi, Tadao
, p. 1678 - 1682 (2007/10/02)
Irradiation of an oxygen-free pentane solution of cis,cis- or cis,trans-cyclo-octa-1,5-diene, (1cc) or (1ct), in the presence of methyl benzoate as sensitizer gave the cis,trans-isomer and tricyclo[3.3.0.0 2,6]octane. However, the tricyclo-octane was not an immediate product from (1cc), but was formed via (1ct). Kinetic evidence and energetic considerations indicate a non-vertical singlet sensitization mechanism involving a singlet exciplex, which in turn falls apart leaving a twisted, excited singlet of the cyclo-octadiene. Two exciplexes, Ex1 and Ex 2, and therefore two twisted singlet cyclo-octadienes, C, 1p and t,1p, are postulated in order to rationalize the different reactivity of (1cc) and (1ct). No evidence for transannular interaction between the two double bonds was found from the quenching rate constants. Correlations between the quenching rate constants and the oxidation potentials of the cyclo-octadienes and cyclo-octenes suggest charge-transfer character for the exciplex. Asymmetric cis-trans photoisomerization sensitized by a chiral aromatic ester also supports the involvement of exciplex with a fairly rigid structure.