Direct Access to Halogenated Fused Imidazo[1,5‐<i>a</i>]<i>N</i>‐heteroaromatics through Copper‐Promoted Double Oxidative C–H Amination and Halogenation

Abstract

An aerobic copper‐promoted double oxidative C–H amination and halogenation tandem reaction of 2‐methylazarenes with aliphatic amines or amino acids has been developed. The reaction uses copper salts as catalysts as well as halogen sources, and molecular oxygen as the sole oxidant. This protocol is operationally simple, and gives direct access to functionalised fused imidazoles in a one‐pot operation with good functional‐group tolerance. The synthetic utility of the products has been tested in a Suzuki cross‐coupling reaction, which proceeded in good yield.