A mechanistic study of the simple sequential N-arylation of piperazine suggests that in an electron-withdrawing group (EWG) containing N-arylated piperazines, hydrogen bonding of the secondary amine hydrogen is important for its non-metal catalyzed conversion to N, N′- diaryl piperazines. A combination of synthetic experiments, molecular modeling, and NMR studies were carried out to test this hypothesis.
