Recent Strategies for the Synthesis of Ferrocene Derivatives and Their Applications to Electrochemistry

Abstract Ferrocene, a highly redox-stable organometallic compound with a distinctive sandwich-like structure, has significantly influenced the fields of electrochemistry, materials science, and medicinal chemistry. Modifying the ferrocene core and its side chains is crucial for fine-tuning its redox properties, solubility, and stability, thereby enhancing its performance in various applications. This review discusses the synthesis of ferrocene compounds potentially relevant to electrochemical applications, focusing on recent strategies for nondirected C–H functionalization of the ferrocene core and diverse reactions for side-chain modifications. Advances in C–H activation of ferrocenes have been facilitated by catalytic methods utilizing Pd, Ir, Au, In, and Fe catalysts, as well as through photoredox and electrochemical techniques. Furthermore, side chains are modified via a range of mild transformations compatible with the ferrocene core, including substitution and annulation. These advancements in synthesizing ferrocene derivatives have broadened their potential applications, notably as electron-transfer mediators, energy-storage systems, and sensors. 1 Introduction 2 Nondirected C–H Activation of Ferrocene and Its Derivatives 3 Side-Chain Modification of Ferrocene Derivatives 4 Applications of Ferrocene Derivatives in Electrochemistry 5 Conclusion