Electron-transfer induced intramolecular [2+2] cycloaddition of 2,6-diarylhepta-1,6-dienes

Article abstract of DOI:10.1016/S0040-4039(00)76711-6

Intramolecular [2+2] cycloaddition of 2,6-diaryl-1,6-heptadienes 1a-c to bicycloheptanes 2 can be induced by electron-transfer photosensitization with 9,10-dicyanoanthracene. A stepwise mechanism involving cyclic 1,4-cation radical 3 has been proposed based on the trapping experiments.