Titanocenes as Photoredox Catalysts Using Green‐Light Irradiation

Irradiation of Cp2TiCl2 with green light leads to electronically excited [Cp2TiCl2]*. This complex constitutes an efficient photoredox catalyst for the reduction of epoxides and for 5‐exo cyclizations of suitably unsaturated epoxides. To the best of our knowledge, our system is the first example of a molecular titanium photoredox catalyst. Green light! For the first time, a titanium complex, Cp2TiCl2, is used in photoredox catalysis. Irradiation with green light enables an efficient catalytic radical chemistry with epoxides under very mild conditions and with reagent control.