Metalation–cyclisation sequence on N-(o-halobenzyl)pyrroles. Synthesis of pyrrolo[1,2-b]isoquinolones

Parham-type cyclisation of N-(o-halobenzyl)pyrroles has been investigated. Aryllithiums generated from metalation of N-(o-iodobenzyl)pyrroles undergo intramolecular cyclisation to give pyrrolo[1,2-b]isoquinolinones in moderate to good yields, if the N,N-diethylcarbamoyl group is used as internal electrophile and the aromatic ring is activated.