Copper-Catalyzed Synthesis Of Primary Arylamines Via Cascade Reaction Of Aryl Halides With Amidine Hydrochlorides

Compounds containing primary arylamines are widely found in natural products, medicines and dyes, and they are usually synthesized through Ullmann cross-coupling reactions. These reactions have recently attracted much attention because of advantages of copper catalysts, such as readily available, inexpensive, low toxicity and air-stability, and their efficiency highly relies on the ligands of copper catalysts. In this thesis, copper-catalyzed synthesis of primary arylamines via cascade reaction of aryl halides with amidine hydrochlorides, and some results were obtained as follows:We have developed an efficient method for synthesis of primary arylamines from aryl halides using acetamidine hydrochlorides as the ammonia surrogates. The protocol uses10mol%Cul as the catalyst,20mol%L-proline as the ligand, CS2CO3as the base and DMF as the solvent. The procedure underwent the sequential coupling of aryl halides with acetamidine hydrochlorides and hydrolysis of intermediates to the target products.The experimental results showed that the catalyst system could promote all examined substrates (aryl halides and amines). Reactivity order for aryl halides is iodides> bromides> chlorides, the reactivity of aryl halides is:acetamidine> butyramidine> benzamidine. Aryl halides containing electron-withdrawing group gave better yields than ones containing electron-donating group, but a higher yield also can be reached with increase of amidine hydrochlorides and temperature. In summary, we have developed an efficient method for synthesis of arylamines.