General procedure for the synthesis of 2-(4-bromophenyl)thiophene from p-bromoiodobenzene and 2-thiophene boronic acid pinacol ester: 1-bromo-4-iodobenzene (2.0 g, 7.07 mmol), 4,4,5,5-tetramethyl-2-(thiophen-2-yl)-1,3,2-dioxaborolane (2.97 g, 14.1 mmol), Pd(PPh3)4 ( 408 mg, 0.35 mmol) and Na2CO3 (1.49 g, 14.1 mmol) were dissolved in a solvent mixture of toluene (40 mL), THF (15 mL) and H2O (15 mL). The reaction mixture was heated to reflux. Upon completion of the reaction (monitored by TLC), the solvent was removed by distillation under reduced pressure, extracted by addition of H2O (30 mL) and CH2Cl2 (40 mL), the organic layer was separated and dried over anhydrous MgSO4. The crude product was purified by silica gel fast column chromatography to afford 2-(4-bromophenyl)thiophene (1.26 g, 74.6% yield). The spectral data of the obtained product were consistent with the values reported in the literature.1H NMR (400 MHz, CDCl3): δ 7.48 (d, J = 3.6 Hz, 4H), 7.29 (d, J = 4.4 Hz, 2H), 7.07 (dt, J = 1.4, 4.4 Hz, 1H).
