CuI-Catalyzed Tandem Intramolecular Amidation Using gem-Dibromovinyl Systems
摘要:
Imidazoindolones are present as the key structural motif in the family of antifungals, fumiquinazolines, and the antagonist asperlicin. The first example of a Cul-catalyzed tandem intramolecular amidation forming substituted imidazoindolones from readily accessible ortho gem-dibromovinylanilines is described.
Rapid, robust, clean, catalyst-free synthesis of 2-halo-3-carboxyindoles
作者:Aaron R. Kunzer、Michael D. Wendt
DOI:10.1016/j.tetlet.2011.02.037
日期:2011.4
A novel synthesis of 2-halo-3-carboxyindoles from 2-(2,2-dihalovinyl)anilines was discovered. Reaction conditions and substrate applicability were studied. Optimally, the reaction takes only minutes when these substrates are heated in DMSO at 120 degrees C in the presence of cesium carbonate. However, the reaction is robust and takes place at a wide range of temperatures, is tolerant of aqueous reaction conditions, and can be performed in a variety of polar solvent/carbonate base combinations where the limiting factor is base solubility. A wide range of substituents is tolerated on the 2-(2,2-dihalovinyl)anilines, and yields are generally high, requiring only acidic aqueous work-up to obtain pure products. No catalyst is required for the transformation. The mechanism is believed to involve initial formation of an alkynyl bromide intermediate followed by ring closure and carbon dioxide trapping, leading to product formation. (C) 2011 Elsevier Ltd. All rights reserved.
Tandem Palladium-Catalyzed N,C-Coupling/Carbonylation Sequence for the Synthesis of 2-Carboxyindoles
作者:Tiago O. Vieira、Laura A. Meaney、Yong-Ling Shi、Howard Alper
DOI:10.1021/ol801985q
日期:2008.11.6
Tandem palladium-catalyzed N,C-coupling/carbonylation, under 10 atm of carbon monoxide and at 110 degrees C, is a novel and efficient method for the preparation of 2-carboxyindoles. The catalyst system tolerates a variety of functional groups, and the noted indoles were obtained in good isolated yields.