An efficient synthesis of 4H-chromene, 4H-pyran, and oxepine derivatives via one-pot three-component tandem reactions

A new and efficient method has been developed for the synthesis of highly functionalized 2-amino-4H-pyran, 2-amino-4H-chromene, 2-amino-oxepine, and 2-hydroxy-oxepine derivatives through one-pot, three-component tandem reactions of structurally diverse 1,3-diketones, dialkyl acetylenedi-carboxylates, and malononitrile or ethyl cyanoacetate in the presence of a catalytic amount of Na2CO3 in ethanol. This efficient technique has the advantages of giving products in good to high yields, in short reaction times, and with a simple isolation procedure. (C) 2012 Elsevier Ltd. All rights reserved.