| Abstract
| - Irradiation of 4-chloroaniline or of its N,N-dimethyl derivative in polar solvents generates thecorresponding triplet phenyl cations. These are trapped by alkenes yielding arylated products inmedium to good yields. B3LYP calculations show that the triplet cation slides with negligibleactivation energy to a bonded adduct with ethylene, whereas it forms only a marginally stabilizedCT complex with water (chosen as a representative σ nucleophile). The structure of the final productsdepends on the preferred path from the adduct cation with the alkene. In the case of aryl olefins,this deprotonates to stilbene derivatives, while, from 2,3-dimethyl-2-butene and allytrimethylsilane,allylanilines are obtained by elimination of an electrofugal group in γ. In the case of mono- anddisubstituted alkenes the cation adds chloride rather than eliminating and β-chloroalkylanilinesare obtained. The regio- and sterochemistry of the addition across the alkene are best understoodwith a phenonium ion structure for the adduct. The nucleophile entering in β can be varied underconditions in which the adduct cation is trapped more efficiently than the starting phenyl cation.Thus, β-methoxyalkylanilines are formed when the irradiation is carried out in methanol.β-Iodoalkylanilines are obtained in acetonitrile containing iodide and unsubstituted alkylanilinesin the presence of sodium borohydride. A case of intramolecular nucleophilic trapping is foundwith 4-pentenoic acid. The reaction is a wide-scope ionic analogue of the radicalic Meerwin arylationof olefins.
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