Sulphur ylide-mediated cyclopropanation and subsequent spirocyclopropane rearrangement reactions

A formal (2 + 1) annulation and three-component (1 + 1 + 1) cascade cyclisation via sulphur ylide cyclopropanation under mild conditions is described, with the spiro-cyclopropyl iminoindoline moiety transformed into pyrrolo[3,4- c ]quinoline through a novel rearrangement process.