Cobalt-catalyzed synthesis of N-containing heterocycles via cyclization of ortho-substituted anilines with CO2/H2

Abstract

The CO₂-involved synthesis of chemicals is of great significance from the green and sustainable chemistry viewpoint. Herein, we report a non-noble metal catalytic system composed of CoF₂, CsF and P(CH₂CH₂PPh₂)₃ (denoted as PP₃) for the synthesis of N-containing heterocycles from ortho-substituted anilines and CO₂/H₂. Mechanism investigation indicates that [Co(PP₃)H(CO₂)]⁺ is a catalytically active intermediate under working conditions; and CsF plays important roles in activating ortho-substituted anilines via hydrogen bond interactions, thus promoting the formation of the final products. This catalytic system is highly efficient, and allows a wide scope of ortho-substituted anilines, together with excellent functional group tolerance, affording various N-containing heterocycles in good to excellent yields.