Generalization of Titanocene-Catalyzed Arylation of Epoxides through Radical Polar Crossover by Consecutive Paired...

Here, we describe the merging of titanocene-catalyzed radical arylation with electro-organic synthesis that combines the advantages of both fields. The critical mechanistic issue of the titanocene-catalyzed radical arylation, the efficiency of rearomatization by a proton-coupled electron transfer, can be efficiently resolved via a radical polar crossover. This is achieved in a unique manner by consecutive paired galvanostatic electrolysis through a decoupling of the electron and proton transfer steps by spatially separating the critical redox processes, the anodic oxidation of the radical σ-complex to the cationic σ-complex, and the mild in situ preparation of the active catalyst by cathodic reduction of Cp₂TiCl₂.