A Copper-Mediated Oxidative Coupling Route to 3H- and 1H-Indoles from N-Aryl-enamines
Pauline Drouhin
Department of Chemistry, University of York Heslington, York, YO10 5DD, United Kingdom, http://www.york.ac.uk/chemistry/staff/academic/t-z/rtaylor/
Search for more papers by this authorCorresponding Author
Richard J. K. Taylor
Department of Chemistry, University of York Heslington, York, YO10 5DD, United Kingdom, http://www.york.ac.uk/chemistry/staff/academic/t-z/rtaylor/
Department of Chemistry, University of York Heslington, York, YO10 5DD, United KingdomSearch for more papers by this authorPauline Drouhin
Department of Chemistry, University of York Heslington, York, YO10 5DD, United Kingdom, http://www.york.ac.uk/chemistry/staff/academic/t-z/rtaylor/
Search for more papers by this authorCorresponding Author
Richard J. K. Taylor
Department of Chemistry, University of York Heslington, York, YO10 5DD, United Kingdom, http://www.york.ac.uk/chemistry/staff/academic/t-z/rtaylor/
Department of Chemistry, University of York Heslington, York, YO10 5DD, United KingdomSearch for more papers by this authorGraphical Abstract
An efficient copper-mediated oxidative coupling approach for the cyclisation of linear enamines to indole derivatives is described. The transformation can be efficiently carried out using inexpensive copper(II) salts.
Abstract
A facile copper(II)-mediated C–H bond oxidation and C–C bond formation procedure has been applied to the synthesis of indole derivatives. Intramolecular oxidative coupling of 3,3-disubstituted enamines proceeded using a non-expensive and air-stable copper salt, Cu(2-ethylhexanoate)2, to afford the corresponding C-3 quaternary indolenine products in good to excellent yields. 1H-Indoles can be prepared in a similar manner but in this case, Cu(OAc)2·H2O has been found to be the preferred oxidant.
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