N, S Co-Coordinated Zinc Single-Atom Catalysts for N-Alkylation of Aromatic Amines with Alcohols: The Role of S-Doping in the Reaction

Ball-milled prepared Fe3O4-FeSAs-NPs@NC catalyst synergistically facilitate the generation of reactive oxygen species for oxidative trifluoromethylation of alkenes

Heterogeneous catalysts have recently regarded as a promising chose for the thermally-driven generation of the reactive oxygen species (ROS) through catalytic reactions with molecular oxygen, which can facilitate this process by specific geometric and electronic structure. However, the oxidative trifluoromethylation of alkenes to α-trifluoromethylated ketones by CF3SO2Na is rarely reported in this system. In this work, we report a one-pot polymerization ball milling strategy to construct precursor, and then pyrolyze it to obtain specific carbon nanotubes matrix with Fe/Fe3O4 nanoparticles and single atoms Fe. Remarkably, the optimized catalyst (Fe3O4-FeSAs-NPs@NC-1) displays excellent catalytic performance, broad substrates and recyclability for this fluorination reaction via radical pathway. Based on characterizations and mechanistic studies, we discover that the coexistence of Fe/Fe3O4 and Fe-Nx not only synergistically facilitates the catalytic efficiency in altering the electronic structure of Fe sites, but also benefits the absorption of O2 and the ability of the thermally-driven generating ROS which can activate CF3SO2Na to CF3 radical. This work offers a method of designing Fe-based catalysts and also opens up a new thermal-heterogeneous catalysis way for the oxidative trifluoromethylation of alkenes.

Titanium-Catalyzed Selective N-Alkylation of Amines with Alcohols via Borrowing Hydrogen Methodology

The N-alkylation of amines with alcohols using earth-abundant and nonprecious metal catalysts has gained considerable attention in the pharmaceutical industry. We described titanium-catalyzed synthetic protocol for N-alkylation of amines with alcohols via borrowing hydrogen or hydrogen autotransfer reactions. The methodology enables the selective monoalkylation of various substituted (hetero)aromatic amines in good to excellent yields (up to 97% yield). The importance of the protocol was further demonstrated by the applicability of earth-abundant metal catalysis and the synthesis of 32 N-alkylated amines. The work allows the utilization of titanium-based catalysts for various reactions to expand the nature blueprint in catalysis.