Improved Synthesis of Pyrroles and Indolesvia Lewis Acid-Catalyzed Mukaiyama–Michael-Type Addition/Heterocyclization of Enolsilyl Derivatives on 1,2-Diaza-1,3-Butadienes. Role of the Catalyst in the Reaction Mechanism
作者:Orazio A. Attanasi、Gianfranco Favi、Paolino Filippone、Samuele Lillini、Fabio Mantellini、Domenico Spinelli、Marco Stenta
DOI:10.1002/adsc.200600362
日期:2007.4.2
The Mukaiyama–Michael-type addition of various silyl ketene acetals or silyl enol ethers on some 1,2-diaza-1,3-butadienes proceeds at room temperature in the presence of catalytic amounts of Lewis acid affording by heterocyclization 1-aminopyrrol-2-ones and 1-aminopyrroles, respectively. 1-Aminoindoles have been also obtained by the same addition of 2-(trimethylsilyloxy)-1,3-cyclohexadiene on some
在一些1,2-二氮杂1,3-丁二烯上在某些催化量的路易斯酸存在下,在一些1,2-二氮杂1,3-丁二烯上进行Mukaiyama-Michael型加成反应,得到各种甲硅烷基乙烯酮缩醛或甲硅烷基烯醇醚,这些反应是由杂环化1-aminopyrrol-2 -一和1-氨基吡咯。通过在一些1,2-二氮杂-1,3-丁二烯上同样添加2-(三甲基甲硅烷氧基)-1,3-环己二烯并随后进行芳构化,也获得了1-氨基吲哚。机理研究表明,路易斯酸对烯丙基甲硅烷基衍生物的配位及其在1,2-二氮杂-1,3-丁二烯的偶氮-烯体系上的1,4-加成反应。甲硅烷基从肼基向酰胺氮的迁移,其酸性裂解和最终的内部杂环化产生最终产物。基于NMR研究和从头算 计算中,给出了甲硅烷基保护基团迁移的合理解释。