1: 4,4'-dibromo biphenyl With magnesium in tetrahydrofuran 2: With boric acid trimethyl ester in tetrahydrofuran T=-78 - 20°C; 3: ethylene glycol in toluene Heating; Further stages.;

n-butyllithium in tetrahydrofuran to soln. 4,4'-dibromobiphenyl in THF at -78°C n-BuLi was added, stirred for 1.5 h, B(OEt)3 was added, stirred for 1 h at -78°C andfor 2 h at room temp., concd. in vacuo, dissolved in ethylene glycol - toluene, refluxed for 2 days; react. mixt. was cooled to room temp., glycol layer was extd. with toluene, toluene fraction was concd. in vacuo, recrystn. from CH2Cl2-hexane (1:5), washing with hexane and drying in vacuo;

1.1: n-butyl lithium / hexane; tetrahydrofuran / -78 - 20 °C 1.2: hexane; tetrahydrofuran / 16 h / 20 °C 2.1: 2.9 g / toluene / 15 h / Heating View Scheme

in toluene 15 h; Heating;