title: Phenonium ions from the addition of phenyl cations to alkenes. Photochemical synthesis of (rearranged) aminoalkylanilines from haloanilines in the presence of alkenes and amines.
abstract: beta-Aminoalkylanilines are smoothly obtained by irradiation of 4-chloro- and 4-fluoroanilines (as well as the N,N-dimethyl derivatives) in the presence of alkenes (1-hexene, cyclohexene) and amines (butylamine, piperidine) in polar, protic solvents such as trifluoroethanol (yield 40-75%). The reaction involves photoheterolysis of the haloaniline, addition of the resulting phenyl cation to the alkene and trapping of the phenonium cation by amine. A fraction (up to ca. 20%) of aminoalkylanilines resulting from Wagner-Meerwein rearrangement of the phenonium cation is obtained in some cases. Reduction and direct trapping of the phenyl cation by the amine compete with the above three-component synthesis in a less stabilizing solvent such as acetonitrile, but not in CF(3)CH(2)OH.
authors.affiliation: Department Organic Chemistry, University of Pavia, Via Taramelli 10, 27100 Pavia, Italy.
authors.forename: Benedetta
authors.initials: B
authors.lastname: Guizzardi
authors.forename: Mariella
authors.initials: M
authors.lastname: Mella
authors.forename: Maurizio
authors.initials: M
authors.lastname: Fagnoni
authors.forename: Angelo
authors.initials: A
authors.lastname: Albini