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

The CuII complex [CuII(dmp)2Cl]Cl (dmp = 2,9‐dimethyl‐1,10‐phenanthroline) is evaluated as an oxidation stable precursor for visible‐light‐mediated CuI‐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 [CuII(dmp)2Cl]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 CuII complexes. The CuII complex [Cu(dmp)2Cl]Cl is introduced to visible‐light photocatalysis, being efficient but considerable more cost‐effective compared to previously established CuI photocatalysts within a broad scope of different reactions. Furthermore, this study provides UV/Vis evidence for the visible light activation of CuII complexes, suggesting an LMCT process resulting in the visible light homolysis of CuII‐Cl to give rise to catalytically active CuI species.