A novel heterotricyclic assembly through intramolecular imino Diels–Alder reaction: synthesis of pyrrolo[3,4-b]quinolines

The synthesis of a series of hexahydropyrrolo[3,4-b]quinolines has been achieved in excellent yields by the reaction of aldimines derived from aromatic amines and N-prenylated aliphatic aldehydes in acetonitrile with InCl3 as a catalyst in a short duration of time.