Photochemical Reaction between 1,4-Naphthalenedicarbonitrile and α-Substituted Benzylic Derivatives

Article abstract of DOI:10.1021/ja00197a041

The photochemical reaction of 1,4-naphthalenedicarbonitrile (NDN) with benzylic derivatives of the general formula PhCHRX (R = H, Ph; X = H, C, O, S, Si, Sn-bonded substituents) has been investigated.The competition between C-H and C-X bond cleavage in the photochemically created radical cation PhCHRX(.+) is revealed by the different chemical products formed, viz. 5,11-methanodibenzocyclooctenes (2), from proton transfer and coupling of the radicals within the cage, and 2-benzyl- (3) and 1-benzyl-1,2-dihydronaphthalenes (4), as well as 4-benzyl-1-naphthalenenitriles (5), from the reaction between the radical anion NDN(.-) and the neutral radicals PhCHR(.) or PhCRX(.).With the alcohols, the hydroxylic proton is easily transferred.Measurement of reaction quantum yield and fluoroscence quenching and thermochemical calculations support the mechanism proposed.