Photocatalytic carboxylation of aryl halides/alkenes with a copper(I) complex bypassing the demand for dual catalysts.

We demonstrate the photocatalytic carboxylation of aryl halides/alkenes using a copper(I)-phen complex as a standalone photocatalyst bypassing the demand for dual metal catalysis or organic dye/metal catalysis. Up to 84% yield is achieved with the use of 10 mol% catalyst. The structure of the copper(I)-phen is confirmed by single crystal XRD analysis. The reaction does not occur in the absence of light (400 nm) and can readily be controlled by light intensity modulation. We also demonstrate that a 25% reaction yield of the carboxylated product can be obtained with iodobenzene under sunlight and the process is equally efficient with a gram scale substrate. Mechanistic insights are achieved with experiments and DFT calculations. These results open the door for a greener approach for carboxylation with a cheap, readily available copper complex under mild reaction conditions.