Synthesis of 2-arylpyrroles via catalytic dehydrogenation of 2-aryl-1-pyrrolines in the presence of palladium-supported on alumina

Different 2-aryl-1-pyrrolines, obtained by cyclisation reaction of 4-chlorobutyronitrile with aryl Grignard reagents, were dehydrogenated in the presence of a commercial palladium-supported on alumina catalyst (Pd/Al2O3), giving rise to the corresponding 2-arylpyrroles in moderate to high yields and selectivities.