An efficient synthesis of (NH)-phenanthridinones via ligand-free copper-catalyzed annulation

Abstract

An efficient and concise procedure for the ligand-free copper-catalyzed cascade reaction of C–O and C–N bond coupling was developed, which afforded various (NH)-phenanthridinones in moderate to good yields with tolerance of a wide variety of substrates. This method could be useful for the syntheses of natural alkaloids.