| Popis: |
Irradiation of an acetonitrile-methanol (4:1) solution containing 1-cyanonaphthalene and allyltrimethylsilane (1) through Pyrex filter (>280 nm) regioselectively gave 3-cyano-4,5-benzotricyclo[4.2.1.0 3,8 ]-4-nonene. The photoreaction of 2-cyanonaphthalene, 1-cyano-2-methylnaphthalene, 1-cyano-4-methylnaphthalene, 1,5- and 2,3-dicyanonaphthalenes with 1 gave the corresponding benzotricyclic compounds also in a regioselective manner. However, the photoreaction of 2,3-disubstituted 1,4-dicyanonaphthalenes with 1 gave no benzotricyclic compounds, but only the allyl substitution and reductive allylation products. These photoreactions were initiated by photoinduced electron transfer from 1 to the excited singlet states of mono- and dicyanonaphthalenes. The reductive allylation products from the former cyanonaphthalenes afforded the benzotricyclic compounds by an intramolecular (2 π +2 π ) photocycloaddition in good yields. The regioselectivity in the allylation reaction is discussed on the basis of the results of MO calculations of the radical anions of mono- and dicyanonaphthalenes. |
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