Unprecedented carbon-carbon bond cleavage in nucleophilic aziridine ring opening reaction, efficient ring transformation of aziridines to imidazolidin-4-ones.

N-Styryl-3-aryl-1-methylaziridine-2-carboxamides, which were readily obtained from the cross coupling reaction between 3-aryl-1-methylaziridine-2-carboxamides and 1-aryl-2-bromoethenes catalyzed by CuI/N,N-dimethylglycine in the presence of Cs(2)CO(3), underwent a base-mediated intramolecular nucleophilic aziridine ring opening reaction effectively via the carbon-carbon bond cleavage of aziridine to afford the ring expanded imidazolidin-4-one products in good yields.