Double Direct C–H\nBond Arylation of Thiophenes\nwith Aryl Chlorides Catalyzed by the <i>N</i>‑Heterocyclic\nCarbene-PdCl<sub>2</sub>‑1-methylimidazole Complex

With\nthe combination of the <i>N</i>-heterocyclic\ncarbene-PdCl<sub>2</sub>-1-methylimidazole complex and Cu<sub>2</sub>O, we succeeded\nin the first example of double direct C–H bond arylation reactions\nbetween thiophenes and aryl chlorides, giving the desired 2,5-diarylated\nthiophenes in moderate to high yields under suitable conditions, consistent\nwith the density functional theory calculations.