Three-Component Azidation of Styrene-Type Double Bonds: Light-Switchable Behavior of a Copper Photoredox Catalyst

[Cu(dap)2]Cl effectively catalyzes azide addition from the Zhdankin reagent to styrene‐type double bonds, and subsequent addition of a third component to the benzylic position. In the presence of light, a photoredox cycle is implicated with polar components such as methanol or bromide adding to a benzylic cation. In the absence of light, by contrast, double azidation takes place to give diazides. Therefore, regioselective double functionalization can be achieved in good to excellent yields, with a switch between light and dark controlling the degree of azidation. Out of the light, into the dark: Copper photoredox catalysis combined with a hypervalent iodine azide reagent enables methoxy azidation of alkenes. In contrast, in the absence of light, the same copper catalyst affords double azidation to give vicinal 1,2‐diazides. The double functionalization proceeds under mild reaction conditions, with a switch between light and dark controlling the degree of azidation. dap=2,9‐bis(p‐anisyl)‐1,10‐phenanthroline.