Nickel-catalysed selective N-arylation or N,N′-diarylation of secondary diamines

The selective synthesis of N-aryl or N,N′-diaryl piperazines and trimethylene(bis)piperidines from the corresponding diamines and aryl chlorides using a catalyst combination of Ni(0) associated to 2,2′-bipyridine is described. The Ni/2,2′-bipyridine catalyst is also effective for the sequential arylation of piperazine. The preparation of novel and unsymmetrical 1,4-diaryl piperazines is reported.