Palladium-catalyzed direct arylation using free NH2 substituted thiophene derivatives with inhibition of amination type reaction

The palladium-catalyzed direct arylation at C2 or CS of free NH2 substituted thiophene derivatives was found to proceed in moderate to high yields using a variety of aryl halides. The choice of potassium acetate as the base was found to be crucial to inhibit the amination reaction and to promote the direct arylation. (C) 2012 Elsevier Ltd. All rights reserved.