Photocatalytic activation of alkyl chlorides by assembly-promoted single electron transfer in microheterogeneous solutions

Photocatalytic activation of alkyl carbon-chlorine bonds has constantly proven difficult due to the high energies needed to cleave this stable bond. Here a surfactant-based photocatalytic system is used, allowing for the radical dehalogenation and subsequent reactivity of unactivated alkyl chlorides. Photoredox catalysis has developed into a powerful tool for the synthesis of organic compounds with diverse structures. However, stable carbon-chloride bonds remain beyond the energetic limits of the outer-sphere photoreductive activation. Here, we demonstrate that the organization of the reacting species in microstructured, aqueous solutions allows generation of carbon-centred radicals from non-activated alkyl chlorides in the presence of double bonds via assembly-promoted single electron transfer. Photocatalytic systems consisting of a surfactant, organic substrates and additives have been designed, characterized and applied for radical dechlorination, addition and cyclization reactions. Cheap and commercially available blue light-emitting diodes are used as the irradiation source for the transformations. Mechanistic studies indicate the accumulation of the energy of two visible light photons in one catalytic cycle.