Redox-photosensitized aminations of 1,2-benzo-1,3-cycloalkadienes, arylcyclopropanes, and quadricyclane with ammonia.
1,2,4-Triphenylbenzene and 2,2'-methylenedioxy-1,1'-binaphthalene successfully photosensitized the aminations of 1,2-benzo-1,3-cycloalkadienes, arylcyclopropanes, and quadricyclane with ammonia and primary amines in the presence of m- or p-dicyanobenzene, which gave the 4-amino-1,2-benzocycloalkenes, 3-amino-1-arylpropanes, and 7-amino-5-(p-cyanophenyl)bicyclo[2.2.1]hept-2-ene, respectively. A key pathway for the photosensitized amination is the hole transfer from the cation radicals of the sensitizers that were generated by photoinduced electron transfer to the electron acceptors to the substrates. Therefore, it was found that the relationships in oxidation potentials between the sensitizers and the substrates and the positive charge distribution of the cation radicals of the substrates were important factors for the efficient amination.