New hetero-bimetallic Pd-Cu catalysts for the one-pot indole synthesis via the Sonogashira reaction

For the first time the one-pot indole synthesis catalyzed by new heterogeneous bimetallic [Pd-Cu] catalysts is described. Based on a domino reaction, 2-phenylindole was synthesized via the Sonogashira C-C coupling reaction with up to 100% yield in short reaction times. In all cases, a complete selectivity towards the indole compound is observed. The heterogeneous catalysts, while being deactivated during the extraction procedure in air, remain highly active and selective when used in a continuous manner. (C) 2003 Elsevier B.V. All rights reserved.