セイタイ トウカセイ キンセキガイコウ デ カッセイカ サレル コウシュヨウセイ ブンシ ノ ゴウセイ ト キノウ

One-way geometrical isomerization around a C=C bond of 1,1-diaryl-2-t-butylethene is achieved upon photoirradiation of cyanoaromatics as a light-absorbing sensitizer. In the thermochemical view, there is no difference between both E and Z isomers of the ethene. In view of the structural resemblance of the ethene to some commercially available antitumor pharmaceuticals, the reaction seems to be of interest to examine extensively. Tuning of wavelength of the light would be possible because the reaction is basically a photocatalytic reaction. Key intermediate is a putative distonic cation radical of which is a unique one having a spatially separated radical and ionic centers on the molecular framework. Generation of such an intermediate is due to the presence of a p-electron donating substituent on an aromatic ring and a bulky t-butyl group. Molecular oxygen interacts as superoxide with the C=C bond of the cation radical in a [supra + antara] manner to give a decomposition product, i.e. a benzophenone derivative and pivalaldehyde, via a dioxetane and competitively, one geometrical isomer of the ethene is afforded by splitting oxygen before making two bonds with the ethene cation radical and superoxide