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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.

The use of lithium bis-catechol borate (LiB(cat)(2)) as a reductive quencher for the photoredox mediated intermolecular C–H functionalization of various heteroaromatics with bromopyrroloindolines is described. LiB(cat)(2) offers a financial benefit over state-of-the-art quenchers currently in use while eliminating the side reactions that typically plague these couplings. The advantage of this methodology is highlighted by the synthesis of C3–C2′ (–) gliocladin C. Furthermore, additional examples of reactivity with various bromopyrroloindolines sets the stage for expedient routes towards other pharmaceutically active hexahydropyrroloindoline alkaloids and their analogues.