Palladium‐ and Copper‐Mediated Direct C‐2 Arylation of Azoles — Including Free (NH)‐Imidazole, ‐Benzimidazole and ‐Indole — Under Base‐Free and Ligandless Conditions

Abstract

AbstractThe first palladium‐ and copper‐mediated C‐2 arylations of thiazole, oxazole, N‐methylimidazole and N‐arylimidazoles, as well as of free (NH)‐imidazole, ‐benzimidazole and ‐indole, with aryl iodides under ligandless and base‐free conditions are described. Complete selectivity has been achieved under these unprecedented conditions, which allow the use of substrates containing base‐sensitive groups, such the NH groups of imidazole, benzimidazole or indole, without their prior protection. No N‐arylation products were detected in the arylation of free (NH)‐imidazole, ‐benzimidazole and ‐indole. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)