Cu/Mn-Catalyzed C–N Cross-Coupling Reaction of Aryl Chlorides and Amines Promoted by a Polyamidoamine Dendrimer.

A bimetallic catalytic combination of Mn(OAc)2 and Cu(OAc)2 was found to be significantly effective for the Buchwald-type C–N cross-coupling of aryl chlorides and amines. The reaction was markedly affected by the presence of a poly(amidoamine) dendrimer as a promoter that also possesses the advantages of being stable, nontoxic, biocompatible, nonimmunogenic, and acting as a soluble support for the transition-metal complex. Although, manganese is cheap and environmentally benign, it has not been fully exploited, due to its low intrinsic catalytic activity. Here, the catalytic potential of manganese was drastically increased by the presence of another metal salt, Cu(OAc)2. In the bimetallic composition, Mn significantly influenced the activity and selectivity, and played a vital role in catalysis. We have developed a novel, green, and economical procedure for Buchwald-type C–N cross-coupling of aryl chlorides and amines. This coupling method works under aerobic and solvent-free conditions and gives excellent yields of value-added N-arylated or N-alkylated products. [ABSTRACT FROM AUTHOR]