Reactions of cerium(IV) ammonium nitrate with aromatic compounds in acetonitrile. Part 1. The mechanism of side-chain substitution

Abstract

Benzene, alkylbenzenes, and phenolic ethers react with cerium(IV) ammonium nitrate in acetonitrile to give nitrocompounds and (if α-hydrogen atoms are present) also the products of side-chain substitution. With many substrates, the major products of side-chain substitution are benzyl nitrates but compounds which can give rise to particularly stable benzyl cations give mainly products from reaction with the solvent. Relative rates of side-chain substitution have been determined by the competition method: the results indicate reaction via a radical cation and the isotope effect k_H/k_D= 2.3 observed in reactions with [²H₁₀]-p-xylene suggests that proton loss from this radical cation is, at least partly, rate-determining.