Aluminum chloride–catalyzed C-alkylation of pyrrole and indole with chalcone and bis-chalcone derivatives

<p>The AlCl₃-catalyzed alkylation of pyrrole (<b>2</b>) with chalcone (<b>1a–i</b>) at a ratio of 8:1 in the presence of 10 mol% AlCl₃ gave the solely 2-alkyl pyrroles (<b>3a–i</b>) at room temperature for 12 in good yields. The same reaction was performed with pyrrole (<b>2</b>) and chalcone at a ratio of 1:3 in CH₃CN at rt for 3 h to achieve 2,5-dialkyl pyrroles (<b>4a–f</b>). In addition, the reaction of the pyrrole (<b>2</b>) and indole (<b>7</b>) on 1,4-phenylene bis-chalcones (<b>5a–g</b>) at the ratio of 8:1 at rt for 24 h gave the double-addition products <b>6a–g</b> and <b>8a–g</b> in good yields, respectively. The structure of the products was confirmed by ¹H and ¹³C NMR spectroscopy and elemental analysis.