Co-N-C Catalyst for C-C Coupling Reactions: On the Catalytic Performance and Active Sites

C-C bond-forming reactions are important in chemistry for construction of complex large molecules from readily available simple substrates. However, they usually involve the employment of organic halides and suffer from toxic or environmental issues. We report an efficient and environmentally benign methodology-aerobic oxidative cross-coupling of primary and secondary alcohols-to directly produce α,β-unsaturated ketones that are key intermediates for synthesis of agrochemical, pharmaceutical, and other fine chemicals. A noble-metal-free Co-N-C catalyst, derived from pyrolysis of cobalt-phenanthroline complexes on a mesoporous carbon support, is developed toward the target reactions and shows high catalytic activity (turnover frequency of 3.8 s^-1 based on Co single atoms, surpassing the state of art in the literature), good recyclability, and wide applicability to diverse substrates (28 examples). The active sites in the Co-N-C catalyst are proposed to be Co single atoms bonded with N within graphitic sheets.