Synthesis of Planar Chiral Ferrocenes via Transition-Metal-Catalyzed Direct C-H Bond Functionalization

Ferrocenes bearing planar chirality have been demonstrated to be highly efficient ligands or catalysts in asymmetric catalysis. In view of their atom and step economies, direct asymmetric C-H bond functionalization is the most concise and powerful method for the construction of planar chiral ferrocenes compared with traditional approaches. This review summarizes recent progress on the development of novel methods to synthesize planar chiral compounds via transitionmetal (Cu-, Pd-, Ir-, Rh-, Au-, Pt-) catalyzed asymmetric C-H bond functionalization. Preparation of a variety of new planar chiral ferrocene-based catalysts and ligands by utilizing these methods and their application in catalytic asymmetric reactions are also discussed.