Photoexcitation of Distinct Divalent Palladium Complexes in Cross‐Coupling Amination Under Air

Abstract

The development of metal complexes that function as both photocatalyst and cross‐coupling catalyst remains a challenging research topic. So far, progress has been shown in Pd0 excited‐state transition metal catalysis for the construction of C–C bonds where the oxidative addition of alkyl/aryl halides to zero‐valent palladium (Pd0) is achievable at room temperature. In contrast, the analogous process with divalent palladium (PdII) is uphill and endothermic. For the first time, we report that divalent PdII can act as a light‐absorbing species that undergoes double excitation to realize C–N cross‐couplings under air atmosphere. Differently substituted aryl halides can be applied in the mild, and selective cross‐coupling amination using Pd(OAc)2 as both photocatalyst and cross‐coupling catalyst at room temperature. Density functional theory (DFT) studies supported by mechanistic investigations provide insight into the reaction mechanism.