Into a 50-mL round-bottom flask purged and maintained with an inert atmosphere of nitrogen, was placed methyl 3-(trifluoromethyl)-1H-pyrrole-2-carboxylate and methyl 3-(perfluoroethyl)-1H-pyrrole-2-carboxylate (300 mg, 1.55 mmol, 1.00 equiv), (4-chlorophenyl)boronic acid (727 mg, 4.65 mmol, 3.00 equiv), Cu(AcO)2 (562 mg, 2.00 equiv), pyridine (491 mg, 6.21 mmol, 4.00 equiv) and dichloromethane (20 mL). The resulting solution was stirred for 2d at 20° C. The solids were filtered out. The resulting residue was applied onto a silica gel column with ethyl acetate/petroleum ether (1:15) to yield methyl 1-(4-chlorophenyl)-3-(trifluoromethyl)-1H-pyrrole-2-carboxylate and methyl 1-(4-chlorophenyl)-3-(perfluoroethyl)-1H-pyrrole-2-carboxylate as yellow oil.
