Formal arylation of NH3 to produce diphenylamines over supported Pd catalysts

In the presence of supported Pd nanoparticle catalysts, e.g., Pd/Al2O3, various diphenylamines could be synthesized through acceptorless formal arylation using NH3 or its surrogates, e.g., urea, as nitrogen sources and cyclohexanones as arylation sources. The observed catalysis was truly heterogeneous, and the catalyst was reusable with retention of its high catalytic performance.