Cycloaddition of Enamine and Iminium Ion Intermediates Formed in the Reaction of N -Arylpyrrolidines with T-HYDRO

Abstract

The reaction of N-arylpyrrolidine derivatives with 70% aqueous tert-butyl hydroperoxide (T-HYDRO) in the presence of NaOAc·3H2O gives tetracyclic amines in 59-78% yields via cycloaddition of the corresponding iminium ion and enamine intermediates formed in situ in cyclohexane solvent. The iminium ion intermediate reacts with t-BuOK in methanol to give the corresponding cyclic amides in 85-88% yields or undergoes alkylation to give the corresponding nitromethyl product in 74-79% yields using t-BuOK and nitromethane in methanol.