Catalyst-free generation of acyl radicals induced by visible light in water to construct C-N bonds

We describe herein a catalyst-free and redox-neutral photochemical strategy for the direct generation of acyl radicals from alpha-diketones, and its selective conversion of nitrosoarenes to hydroxyamides or amides with AcOH or NaCl as an additive. The reaction was carried out under mild conditions in water with purple LEDs as the light source. A broad scope of substrates was demonstrated. Mechanistic experiments indicate that alpha-diketones cleave to give acyl radicals, with hydroxyamides being further reduced to amides.