Lewis Acid Mediated Aminobenzannulation Reactions of δ-Ketoalkynes: Synthesis of 1-Aminocarbazoles and 9-Aminopyrido[1,2-<i>a</i>]indoles
作者:Diego Facoetti、Giorgio Abbiati、Elisabetta Rossi
DOI:10.1002/ejoc.200900039
日期:2009.6
2-Acyl-N-propargylindoles 1 and 2-acyl-3-propargylindoles 5 undergo aminobenzannulation reactions with pyrrolidine in the presence of an appropriate Lewis acid to give 9-aminopyrido[1,2-a]indoles 6 and 1-aminocarbazoles 7, respectively. The selection of the appropriate Lewis acid, TiCl4 or GaCl3 for 1 and InCl3 for 5, allows the domino process involving the initial formation of an enamine intermediate
2-酰基-N-炔丙基吲哚1和2-酰基-3-炔丙基吲哚5在适当的路易斯酸存在下与吡咯烷发生氨基苯并化反应,得到9-氨基吡啶并[1,2-a]吲哚6和1-氨基咔唑7,分别。选择合适的路易斯酸,TiCl4 或 GaCl3 为 1,InCl3 为 5,允许多米诺骨牌过程涉及初始形成烯胺中间体,然后区域选择性 6-exo-dig 分子内亲核攻击不饱和的亲核末端系统(烯氨基部分的β-碳)连接到碳-碳三键。此外,还报告了有关反应机理和两种催化剂作用的几个特征,以及反应炔烃的电子性质。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)