Novel synthesis of azepine derivatives via copper-mediated cyclization of 2-aza-hepta-2,4-dien-6-ynyl anions. Intramolecular addition of organocopper centers to the C-C triple bond

Abstract

Deprotonation of alkynyl imines 1 with LDA at low temperature and subsequent transmetalation with copper thiophenolate gives the annulated azepines 11a-i in 41-73% yield after aqueous workup. The key step of the reaction is a copper-mediated intramolecular nucleophilic attack at the triple bond. [reaction: see text]