Visible Light-Induced Aerobic Oxidation of Diarylalkynes to -Diketones Catalyzed by Copper-superoxo at Room Temperature

We have developed the visible light induced simple copper(II) chloride catalyzed the oxidation of diarylacetylenes to -diketones by molecular oxygen at room temperature. The in-situ generated copper(II)-superoxo complex is a light-absorbing species that oxidizes inert diarylacetylenes to -diketones. In contrast to reported photochemical processes, the current oxidation protocol does not require any exogenous photocatalyst or radical initiator. The green chemistry metrics evaluation signifies that the E-factor for the current oxidation process is ~2.3 times better than that of reported photochemical processes. The current reaction scores 63 on the EcoScale of 0-100, indicates an adequate synthesis process. Thus, the overall oxidation process is simple, environmentally benign, and economically feasible.