Anionic aza 8π-electrocyclization as an unprecedented pathway 7-: DFT study on the mechanism of base-catalyzed benzofuroazepine synthesis cyclization of (2-alkynylbenzyl)oxy nitriles.

DFT calculations are used to disclose the mechanism of Brønsted base-mediated cyclization of (2-alkynylbenzyl)oxy nitriles for the synthesis of benzofuroazepines. In 2015, the synthesis of substituted benzofuroazepines was reported by Zeni a stepwise mechanism known as 7-. However, DFT calculations revealed that the anionic aza 8π-electrocyclization is more favorable than the proposed 7- mechanism.