Lithium bis-catechol borate as an effective reductive quencher in photoredox catalysis

The use of lithium bis-catechol borate (LiB(cat)(2)) as a reductive quencher for the photoredox mediated intermolecular CH 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. (C) 2018 Elsevier Ltd. All rights reserved.