Metal-Free Photoredox-Catalyzed C–H/C–H Coupling of Arenes Enabled by Interrupted Pummerer Activation
Preprints are manuscripts made publicly available before they have been submitted for formal peer review and publication. They might contain new research findings or data. Preprints can be a draft or final version of an author's research but must not have been accepted for publication at the time of submission.
Aryl–aryl cross-coupling constitutes one of the most widely used procedures for the synthesis of high-value materials, ranging from pharmaceuticals to organic electronics and conducting polymers. The assembly of (hetero)biaryl scaffolds generally requires multiple steps; coupling partners must be functionalized before the key bond-forming event is considered. Thus, the development of selective C–H arylation processes in arenes, that side-step the need for prefunctionalized partners, is crucial for streamlining the construction of these key architectures. Here we report an expedient, one-pot assembly of (hetero)biaryl motifs using photocatalysis and two non-prefunctionalized arene partners. The approach is underpinned by the activation of a C–H bond in an arene coupling partner using the interrupted Pummerer reaction. A unique pairing of the organic photoredox catalyst and the intermediate dibenzothiophenium salts enables highly selective reduction in the presence of sensitive functionalities. The utility of the metal-free, one-pot strategy is exemplified by the synthesis of a bioactive natural product and the modification of complex molecules of societal importance.