Copper/BINOL-Catalyzed Enantioselective C-H Functionalization towards Planar Chiral Ferrocenes Under Mild Conditions

Copper-catalyzed enantioselective C–H activation proceeds through inner-sphere mechanism remains a huge challenge. Herein, a copper-catalyzed enantioselective C−H alkynylation with terminal alkynes assisted by 8-aminoquinoline using readily available (S)-BINOL as chiral ligand was disclosed. The reaction proceeded under mild conditions with a catalytic amount of copper salt, providing a range of chiral ferrocenes in good yields and enantioselectivities (0 oC, up to 77% yield and 94% ee). The alteration of stoichiometric chemical oxidant with renewable electricity is also feasible at ambient temperature, demonstrating the robustness of this copper/BINOL catalysis. Notably, this is the first enantioselective cupraelectro-catalyzed C-H activation reaction. Gram-scale synthesis, versatile transformations, and application of the resulting oxazoline-olefin ligand in asymmetric synthesis also highlight the utility of the protocols.