Synthesis of substituted β-carbolines via gold(III)-catalyzed cycloisomerization of N-propargylamides
作者:Guido Verniest、Dylan England、Norbert De Kimpe、Albert Padwa
DOI:10.1016/j.tet.2009.10.033
日期:2010.2
Indole-substituted N-propargylamides undergo a gold(III)-catalyzed cyclization to give oxazoles or beta-carbolinones, depending on the Substitution pattern at the amide nitrogen. Secondary amides furnished oxazoles via a 5-exo-dig cyclization, while tertiary indole-2-carboxamides cycloisomerized to give 2,9-dihydro-beta-carbolin-1-ones upon treatment with catalytic amounts of gold(III) chloride. An optimized procedure was developed to prepare several new N-benzyl-beta-carbolinones as well as the corresponding beta-carbolines, which are of interest as core structures found in various natural products such as the harman, ervolanine, and lavendamycin class of alkaloids. (C) 2009 Elsevier Ltd. All rights reserved.