Photoredox catalysts: synthesis of the bipyrazine ligand.

The bipyrazine ligand is often employed in photoredox catalysts in order to increase the excited state oxidation potential of the catalyst. However, literature syntheses of the ligand are cumbersome and typically lead to low yields. This hampers use of the desired catalysts. We report here an efficient copper based synthesis of the bipyrazine ligand that affords the product in 65-76% yield on a multigram scale.