Formation and trapping of azafulvene intermediates derived from manganese-mediated oxidative malonate coupling. Issue 26 (30th June 2016)

• Record Type: Journal Article
• Authors: Lofstrand, Verner A.; Matsuura, Bryan S.; Furst, Laura; Narayanam, Jagan M.R.; Stephenson, Corey R.J.
• Is Part Of: Tetrahedron. Volume 72:Issue 26(2016)
• Page Start: 3775
• Page End: 3780
• Publication Date: 2016-06-30
• Subjects: Oxidative coupling -- Radical reaction -- Heterocycle functionalization -- C–H functionalization; Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tet.2016.03.012
• Languages: English
• ISSNs: 0040-4020

Abstract

Abstract: The one-pot, three-component, coupling reaction of indoles/pyrroles, dimethyl malonate, and acetic acid was performed using Mn(III) acetate as an oxidant. In the presence of Mn(OAc)3, indole-2, and indole-3-carbonyl compounds were alkylated at the 3- and 2- positions, respectively, with subsequent oxidation and nucleophilic capture occurring at the newly formed benzylic carbon. In contrast, oxidation of 2- and 3-indole carboxylic acids afforded the corresponding 2-oxindol-3-ylidenes and 3-oxindol-2-ylidenes. The reaction conditions, scope, and mechanism are discussed herein. Graphical abstract: