Iron(II) Triflate as a Catalyst for the Synthesis of Indoles by Intramolecular C-H Amination
Julien Bonnamour and Carsten Bolm*
*Institute of Organic Chemistry, RWTH Aachen University,
Landoltweg 1, D-52056 Aachen, Germany, Email: carsten.bolm
oc.rwth-aachen.de
J. Bonnamour, C. Bolm, Org. Lett., 2011, 13, 2012-2014.
DOI: 10.1021/ol2004066
Abstract
A practical iron-catalyzed intramolecular C-H amination reaction with commercially available iron(II) triflate as catalyst can be used for the synthesis of indole derivatives.
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General procedure for metal-catalyzed cyclizations of aryl azidoacrylates
A sealable tube equipped with a magnetic stir bar was charged with the aryl azidoacrylates (100 mg, 1.0 equiv) and Fe(OTf)2 (10 mol %). The aperture of the tube was then covered with a rubber septum, and an argon atmosphere was established. THF (1 mL) as added by syringe. The septum was then replaced by a teflon-coated screw cap, and the reaction vessel was placed in an oil bath (80 °C). After stirring at this temperature for 24 h, the mixture was cooled to room temperature and diluted with dichloromethane. The resulting solution was directly filtered through a pad of celite, washed with water, extracted with dichloromethane and concentrated to yield the product, which was purified by silica gel chromatography to yield the corresponding indole as a white solid. The identity and purity of the product was confirmed by 1H and 13C NMR spectroscopic analysis.
Key Words
ID: J54-Y2011-1090
