Polystyrene-supported palladium(II) ethylenediamine complex: A highly active and recyclable catalyst for the synthesis of 2-benzylimidazo[2,1-<i>b</i>]pyridines through heteroannulation of acetylenic compounds
The polymer-supported palladium(II) ethylenediamine [PS-en-Pd(II)] complex is a highly active catalyst for the heterocyclization that takes place during the Sonogashira reaction between an aryliodide and 2-amino-1-(2-propynyl)pyridinium bromide. This heterogeneous palladium catalyst can readily be recovered from the reaction medium by simple filtration and reused without a significant loss in its
The reaction of 2-amino-1-(2-propynyl)pyridinium bromide with various iodobenzenes, catalyzed by Pd-Cu, leads to the formation of 2-benzylimidazo[1,2-a]pyridines. (C) 2008 Elsevier Ltd. All rights reserved.