The selective functionalization of chemically inert C−H bonds remains to be fully realized in achieving organic transformations that are redox‐neutral, waste‐limiting, and atom‐economical. The catalytic generation of chlorine atoms from chloride ions is one of the most challenging redox processes, where the requirement of harsh and oxidizing reaction conditions renders it seldom utilized in synthetic applications. We report the mild, controlled, and catalytic generation of chlorine atoms as a new opportunity for access to a wide variety of hydrogen atom transfer (HAT) reactions owing to the high stability of HCl. The discovery of the photoredox mediated generation of chlorine atoms with Ir‐based polypyridyl complex, [Ir(dF(CF3)ppy)2(dtbbpy)]Cl, under blue LED irradiation is reported.

A protocol for direct C–H alkylation of heteroarenes was developed using photoredox catalysis as a mode of activation for unactivated bromoalkanes. Dimeric Au(i) complex, [Au2(dppm)2]Cl2, served as an efficient photocatalyst for this transformation.

International audienceWe thank the Natural Sciences and Engineering Research Council (for Accelerator and Discovery grants to L.B.) and the University of Ottawa (for a University Research Chair to L.B.) for support of this research. We also thank Prof. Derek Pratt (University of Ottawa) for insightful discussion

The functionalization of heteroarenes has been integral to the structural diversification of medicinally active molecules such as quinolines, pyridines, and phenanthridines.

The light mediated reduction of unactivated carbon–halogen bonds using polynuclear gold(i) complexes provides a mild and temporally controlled route to the generation of C–H, and C–C bonds.