Metal-free benzannulation of 1,7-diynes toward unexpected 1-aroyl-2-naphthaldehydes and their application in fused aza-heterocyclic synthesis

Ai-Fang Wang, Peng Zhou, Yi-Long Zhu, Wen-Juan Hao,* Guigen Li, Shu-Jiang Tu,* and Bo Jiang*

A novel I₂-mediated benzannulation of 1,7-diynes involved 1,4-oxo-migration has been established, providing a range of unexpected 1-aroyl-2-naphthaldehydes with a 1,4-dicarbonyl unit. The resulting 1-aroyl-2-naphthaldehydes have been successfully applied in the synthesis of benzo[e]isoindol-3-ones and benzo[e]benzo[4,5]imidazo[2,1-a]isoindoles using aromatic amines and benzene-1,2-diamines as nucleophiles, respectively. The mechanisms for forming these compounds were proposed.

Chem. Commun. 2017, 53, 3369-3372