A new approach to 10-arylated 5H-dibenzo[b,f]azepines using syn-selective hydrohalogenation of ethynylaniline

Abstract

A new synthetic method for 10-arylated dibenzo[b,f]azepines was developed. The pseudo-intramolecular hydrohalogenation of 2-(2′-bromophenyl)ethynylaniline, which proceeded in a syn-selective manner without forming any detectable over-addition product, was a crucial step. All attempts of subsequent arylation via Suzuki–Miyaura cross coupling and construction of a seven membered ring via Ullmann-type intramolecular coupling were unsuccessful because of dehydrohalogenation or other side reactions. This problem was overcome by the N-acetylation of the amino group, which facilitated the abovementioned coupling reactions to afford the desired 10-arylated dibenzoazepines.