Irradiation of an acetonitrile solution of cis 1-methyl-2-phenylcyclopentane (1 b cis); 1, 4- dicyanobenzene (2), an electron-accepting photosensitizer; and 2, 4, 6-collidine (3), a nonnucleophilic base, leads to configurational isomerization of the cyclopentane; the photostationary state lies> 99% in favour of the trans isomer. The mechanism proposed for this reaction involves formation of the radical cation of 1 b cis by photoinduced electron ...
