AMVN-initiated expedient synthesis of biaryls by the coupling reaction of unactivated arenes and heteroarenes with aryl iodidesElectronic supplementary information (ESI) available: NMR (1H, 13C, and 13C-DEPT-135) spectra of biaryls 1-40 and EPR spectra of the reaction mixture. See DOI: 10.1039/c3nj01105d

The role of radical initiators AMVN and AIBN has been studied in the potassium tert -butoxide mediated biaryl coupling reaction of aryl iodides with unactivated arenes. Radical initiator AMVN promoted carbon-carbon bond formation expeditiously from aryl iodide having various groups such as amino, methoxy, fluoro, methyl, and trifluoromethyl and arenes in the presence of potassium tert -butoxide (4 equiv.) at 110 °C in 2-5 h. Substituted arenes such as toluene, xylene, anisole, and fluorobenzene also proceeded to form biaryls under AMVN-initiated reaction conditions. Moreover naphthalene, pyridine, pyrimidine, and pyridazine also coupled with aryl iodides and produced biaryls in 41-82% yields. It seems that AMVN initiates the formation of the aryl radical, which enters the radical chain reaction. The generated aryl radical may combine with the arene leading to a biaryl radical, which upon protonation gives the biphenyl radical anion and tert -butanol. The biphenyl radical anion finally reacts with the aryl iodide generating the aryl radical and thus completes the radical chain reaction with concomitant release of biphenyl. A transition metal free carbon-carbon bond forming reaction for the synthesis of biaryls and heterobiaryls has been presented in this work.