An unusual ring closure reaction with formation of pyrrolidin-2,5-dione derivatives
Abstract
Mild oxidation of amidine (1) bearing two sterically crowded phenol moieties leads to the formation of the dispirocyclohexadienone derivative (6) of pyrrolidin-2,5-dione N-arylamine through an intramolecular ring closure recombination of the intermediate biradical (4).