Metal-Free Photoredox-Catalysed Formal C–H/C–H Coupling of Arenes Enabled by Interrupted Pummerer Activation
David Procter reports the use of the interrupted Pummerer reaction for C–H functionalisation processes.
(Hetero)biaryl scaffolds are ubiquitous in the molecules that drive the main chemical industries. Such motifs are most commonly assembled using transition-metal-catalysed cross-couplings; however, the requirement to pre-functionalise both coupling partners and the use of precious-metal catalysts can result in costly procedures that produce substantial amounts of waste. According to Professor David Procter – an expert of cross-coupling chemistry and catalysis at the University of Manchester (UK) – a strong movement has recently formed within the synthetic community with the aim of developing (i) cross-couplings of non-pre-functionalised partners, that take place at the expense of C–H bonds, and (ii) cross-couplings that operate without using metals. His group has recently developed a range of C–H functionalisation processes that utilise the so-called interrupted Pummerer reaction of sulfoxides.