Making Copper Photocatalysis Even More Robust and Economic: Photoredox Catalysis with [CuII(dmp)2Cl]Cl

The Cu II complex [Cu II (dmp) 2 Cl]Cl (dmp = 2,9‐dimethyl‐1,10‐phenanthroline) is evaluated as an oxidation stable precursor for visible‐light‐mediated Cu I ‐photoredox catalysis, being efficient and considerable more cost‐effective compared to previously established copper(I) photocatalysts. Its performance and efficiency are demonstrated within a broad scope of atom transfer radical addition (ATRA) reactions, allowing the 1,2‐difunctionalization of alkenes, as well as for decarboxylative coupling and an Appel reaction. Moreover, the utility of the complex is shown by various gram‐scale functionalizations of styrene, thus suggesting [Cu II (dmp) 2 Cl]Cl to be a low‐priced alternative precatalyst for processes run on scale. Furthermore, this study provides UV/Vis evidence on the mechanism for the visible light activation of Cu II complexes.