# Titanocenes as Photoredox Catalysts Using Green‐Light Irradiation

## TL;DR

A titanium complex is used for the first time in photoredox catalysis, enabling efficient chemical reactions under green light.

## Contribution

This is the first example of a molecular titanium photoredox catalyst using green-light irradiation.

## Key findings

- Cp2TiCl2 acts as an efficient photoredox catalyst for reducing epoxides.
- The catalyst enables 5-exo cyclizations of unsaturated epoxides under mild conditions.

## Abstract

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.