The freshly prepared LDA solution (prepared by the addition ofn-BuLi (2.5 M in hexanes, 100 mmol, 40 mL) and diisopropylamine(11.1 g, 110 mmol) in 50 mL of anhydrous THF (78 C to roomtemperature)) was added drop wise to a solution of 3-bromothiophene (16.30 g, 100 mmol) in anhydrous THF (100 mL)at 78 C under nitrogen atmosphere. The reaction mixture wasstirred for 1 h at 78 C and CuCl2 (14.11 g, 105 mmol)was added inone portion. The reaction mixture was allowed towarm up to roomtemperature and treated with aqueous HCl. The organic phaseseparated was collected and the aqueous phase was extracted withdiethyl ether several times. The combined organic phase was driedover anhydrous Na2SO4 and the solution was filtered, concentratedand the residue was purified by silica gel column chromatography(hexane eluent) to afford a the required compound as white solid(yield 85%).1H NMR (500 MHz, CDCl3, d ppm): 7.08 (d, J 5.0 Hz, 2H), 7.40(d, J 5.0 Hz, 2H).
