Photochemical Reaction of 1,4-Naphthalenedicarbonitrile with Alkylbenzenes and Bibenzyls

Article abstract of DOI:10.1021/ja00274a044

The photochemical reaction of 1,4-naphthalenedicarbonitrile with some alkylbenzenes and bibenzyls has been examined.A unitary mechanistic picture is formulated on the basis of product study, deuteration experiments, and fluorescence and reaction quantum yield measurements.Proton transfer within the singlet radical ion pair followed by in-cage cycloaddition of the two radicals yields stereoselectively 5,11-methanodibenzo cyclooctene derivatives (8).Reaction of benzyl radicals (formed by protolysis or, for radical cations having no benzylic proton, by C-C bond cleavage) with unprotonated NDN^.- leads, again stereoselectively, to 2-benzyl-1,2-dihydronaphtalenes (9).Escape of the donor radical cation and following C-H or C-C bond cleavage leads to a different product, thus, benzyl radicals are trapped by NDN to yield substitution products (11) or recombine.Benzyl cations are trapped by nucleophiles.