The development of strong covalent interactions in inner sphere electron transfer reactions between cation radicals and neutral molecules

The cation radical Diels-Alder reactions of a series of meta and para subst ituted aryl cis-prop-1-enyl ethers with 2,3-dimethylbuta-1,3-diene catalyze d by tris(4-bromophenyl)aminium hexachloroantimonate have been studied mech anistically. The reactions are found to occur primarily via an indirect rou te involving cation radical cyclo-butanation followed by cation radical vin ylcyclobutane rearrangement. Kinetic studies reveal that the ionization of these ethers to the corresponding cation radicals occurs by an inner sphere mechanism.