title: Efficient unimolecular deprotonation of aniline radical cations.
abstract: [reaction: see text] Deprotonation of the radical cations of aromatic amines, such as anilines, generally occurs much more slowly than other fragmentation reactions. Here we report a stereoelectronic effect involving twisting of the anilino group out of the plane of the benzene ring that results in a significantly increased rate of reactivity toward deprotonation. Quantitative studies of the rate constants for deprotonation as a function of aniline radical cation pKa (Brønsted plots) demonstrate that the effect is not simply due to a change in the reaction thermodynamics. By combining this stereoelectronic effect with covalent attachment of carboxylate as a base, aniline radical cations that undergo unimolecular deprotonation with rate constants as high as 10(8) s(-1), even in unfavorable protic media, are described.
authors.affiliation: Department of Chemistry, University of Rochester, Rochester, New York 14627-0216, USA.
authors.forename: Gary W
authors.initials: GW
authors.lastname: Dombrowski
authors.forename: Joseph P
authors.initials: JP
authors.lastname: Dinnocenzo
authors.forename: Paul A
authors.initials: PA
authors.lastname: Zielinski
authors.forename: Samir
authors.initials: S
authors.lastname: Farid
authors.forename: Zofia M
authors.initials: ZM
authors.lastname: Wosinska
authors.forename: Ian R
authors.initials: IR
authors.lastname: Gould