Cu(I) mediated one-pot synthesis of azobenzenes from bis-Boc aryl hydrazines and aryl halides

N,N'-bis-Boc aryl hydrazines underwent Cu(I) catalyzed couplings with aryl halides to provide N,N'-bis-Boc diaryl hydrazines. The resulting N,N'-bis-Boc diaryl hydrazines are readily oxidized to the azobenzenes in the presence of Cu(I) and a base. A prolonged heating of the initial coupling reactions directly provides the corresponding azobenzenes in one pot. (C) 2003 Elsevier Ltd. All rights reserved.