Ni/Ir-Catalyzed Photoredox Decarboxylative Coupling of S-Substituted Thiolactic Acids with Heteroaryl Bromides: Short Synthesis of Sulfoxaflor and Its SF5 Analog

Metallaphotoredox cross-coupling reactions have recently emerged as a powerful tool for the construction of C(sp(2))-C(sp(3)) bonds between alkyl chains and aromatic systems, including electron-deficient heteroaryls, which are known to be challenging coupling partners. In this article, we disclose the Ni/Ir-catalyzed photoredox de-carboxylative coupling of readily available S-substituted thiolactic acids with electron-deficient heteroaryl bromides, which resulted in the formation of simple but otherwise not easily accessible heteroarenes with alkylsulfide side chains. To demonstrate a practical use of this coupling reaction, we have shown its efficiency in the one-step synthesis of a key intermediate in the synthesis of the recently marketed insecticide Sulfoxaflor, and for the short synthesis of SF5-Sulfoxaflor.