Generating Hydrated Electrons for Chemical Syntheses by Using a Green Light‐Emitting Diode (LED)

We present the first working system for accessing and utilizing laboratory‐scale concentrations of hydrated electrons by photoredox catalysis with a green light‐emitting diode (LED). Decisive are micellar compartmentalization and photon pooling in an intermediate that decays with second‐order kinetics. The only consumable is the nontoxic and bioavailable vitamin C. A turnover number of 1380 shows the LED method to be on par with electron generation by high‐power pulsed lasers, but at a fraction of the cost. The extreme reducing power of the electron and its long unquenched life as a ground‐state species are synergistic. We demonstrate the applicability to the dechlorination, defluorination, and hydrogenation of compounds that are inert towards all other visible‐light photoredox catalysts known to date. A comprehensive mechanistic investigation from microseconds to hours yields results of general validity for photoredox catalysis with photon pooling, allowing optimization and upscaling.