An efficient synthesis of quinolones using N-phenyl(triphenylphosphoranylidene)ethenimine

Abstract The acylphosphoranes 5 formed in a highly selective and sequential manner from the reaction of N-substituted anthranilic acids 1 and N-phenyl(triphenylphosphoranylidene)ethenimine 2 undergo intramolecular Wittig cyclization on the imide carbonyl to afford the pyrrolo- and pyrido[1,2-a]quinolones 6 in moderate to good yields.