Herein we present an investigation into the scope and mechanism for the synthesis of cyclopentyl and heterocyclic fused pyridones from the corresponding enyne amides. In the presence of a secondary amine, cyclization proceeds smoothly to form 5,6-bicyclic pyridones in 12–90% yield. The cyclization fails with enyne amides of six-membered and larger ring systems. The ring closure reaction is catalytic
在此,我们对从相应的烯炔酰胺合成环戊基和杂环稠合
吡啶酮的范围和机制进行了研究。在仲胺的存在下,环化顺利进行,以 12-90% 的产率形成 5,6-双环
吡啶酮。六元和更大环系统的烯炔酰胺环化失败。闭环反应对于仲胺而言本质上是催化性的,并且通过胺的顺序1,6-加成、
亚胺中间体的6-外-
三环闭环以及随后的仲胺的消除进行。计算表明,对于六元和更大的系统,烯炔和酰胺之间的共轭减少,从而为此类烯炔酰胺无法形成稠合
吡啶酮提供了解释。