“De Novo” Construction of Planar-Chiral Ferrocenes via Palladium/Chiral Norbornene Cooperative Catalysis

Transition-metal-catalyzed asymmetric C–H functionalization has emerged as a powerful strategy for constructing planar-chiral ferrocenes (PCFs). However, current methods typically require preinstallation of a directing group (DG) and are usually limited to monofunctionalization. Herein, we report a “de novo” construction of PCFs via Pd/NBE* cooperative catalysis, employing a unique bulky (C1,C4)-bridgehead-modified chiral norbornene as the cocatalyst as well as the only chiral source. This approach enables the formation of two new chemical bonds in a single step from simple iodoferrocenes. A series of planar-chiral isoquinolone-fused ferrocenes are quickly obtained with up to >99% ee. Mechanistic studies reveal that the ortho-C–H activation step serves as the enantio-determining step, while the reductive elimination is not only the rate-determining step but also plays a pivotal role in further enhancing the enantioselectivity. The synthetic utility is highlighted by diverse transformations of products and the development of a powerful NAD(P)H coenzyme for biomimetic asymmetric hydrogenation of olefins.