Mesoporous nitrogen-doped carbon for copper-mediated Ullmann-type C–O/–N/–S cross-coupling reactions

Abstract

Copper-driven Ullmann-type cross-coupling reactions are regarded as one of the most important methods for the C–O, C–N, C–S and some other bonds formation. Herein, we report that mesoporous nitrogen-doped carbon materials with high nitrogen content function as novel, active and recyclable N-type heterogeneous promoters for copper-catalyzed cross-couplings. By using CuI as the catalyst and a mesoporous nitrogen-doped carbon material as the promoter, the Ullmann-type coupling reactions of various aryl halides with phenols, amines, imidazol, and thiophenols at 100 °C gave the corresponding products in good yields. Inspired by the efficiency of mesoporous nitrogen-doped carbon material as a promoter, nitrogen-doped carbon supported CuO nanoparticles are prepared and successfully employed as efficient heterogeneous catalysts in the C–O cross-coupling reactions. Furthermore, the nitrogen-doped carbon material supported CuO can be simply recycled by centrifugation and reused at least four times with trace copper leaching. The mesoporous nitrogen-doped carbon materials as heterogeneous promoters or copper-based catalyst supports may represent a promising catalyst system in modern Ullmann chemistry, which indeed could lead to improved processing steps.