Into a 50-mL sealed tube (1 atm) purged and maintained with an inert atmosphere of nitrogen, was placed methyl 5-methyl-3-(((trifluoro methyl)sulfonyl)oxy)thiophene-2-carboxylate (1.7 g, 5.59 mmol), (4-ethylphenyl)boronic acid (1.0 g, 6.69 mmol), K3PO4 (3.84 g, 18.1 mmol), Pd(PPh3)4 (157 mg, 0.136 mmol), 1,4-dioxane (40 mL). The resulting solution was stirred overnight at 80° C. in an oil bath. The reaction progress was monitored by TLC/LCMS (ethyl acetate/petroleum ether=1:6). The solids were filtered out and washed by 20 mL ethyl acetate. Collected the organic phases and concentrated under vacuum. The residue was applied onto a silica gel column with ethyl acetate/petroleum ether (1:10). This resulted in 1.46 g (100%) of methyl 3-(4-ethylphenyl)-5-methylthiophene-2-carboxylate as light yellow oil.
