Photoredox-catalyzed synthesis of N-unsubstituted enaminosulfones from vinyl azides and sulfinates

• Photoredox-catalyzed reaction of vinyl azides and sulfinates gives enaminosulfones. • Eosin Y and PhNO 2 were used as a photocatalyst and an electron shuttle respectively. • Release of N 2 allows the energetically favorable formation of enamine derivatives. • Fluorescence quenching experiments with eosin Y confirmed oxidative quenching route. A metal-free visible light photoredox-catalyzed synthesis of N -unsubstituted enaminosulfones from vinyl azides and sodium sulfinates in moderate to high yields is described. The reaction proceeds in ethanol and uses eosin Y as a readily available photocatalyst in combination with nitrobenzene as an electron shuttle. Taking into account the number of steps involved (generation of the sulfonyl radical, its addition to the double bond, elimination of molecular nitrogen with formation of an iminyl radical, followed by its reduction and protonation) as well as the number of redox-active reaction partners involved, the selectivity of the process is quite impressive.