CuI/4-Hydro-L-proline as a More Effective Catalytic System for Coupling of Aryl Bromides with N-Boc Hydrazine and Aqueous Ammonia

CuI/4-hydroxy-L-proline-catalyzed coupling of aryl bromides and N-Boc hydrazine takes place in DMSO at 80 degrees C to give N-aryl hydrazides. When aryl iodides are employed, this reaction completes at 50 degrees C and no ligand is required. Under the catalysis of CuI/4-hydroxy-L-proline, the coupling reaction of aqueous ammonia with aryl bromides proceeds smoothly at 50 degrees C to afford primary arylamines. In this case K2CO3 is found as a better base than Cs2CO3. These processes allow assembly of N-aryl hydrazides and primary arylamines that bear a wide range of functional groups including hydroxyl, amine, trifluoromethyl, ester, nitro, and ketone.