Manganese(I) Catalyzed ortho C−H Allylation of Benzoic Acids

The 3d-metal catalyst Mn(CO)₅Br was found to efficiently promote ortho C−H allylations of arenecarboxylates in the presence of neocuproine as the ligand. Despite the simplicity of directing group and catalyst system, the selectivity goes well beyond the state-of-the-art in that mono-allylated products are obtained exclusively with high selectivities for the least hindered ortho-position. The directing group can optionally be removed by in situ decarboxylation, opening up a regioselective entry to allyl arenes. The preparative utility of the process and its othogonality to other approaches was demonstrated by 44 products with otherwise hard-to-access substitution patterns, including 3-bromo-allylbenzene, 3-allylbenzofuran, or 5-allyl-2-methylnitrobenzene.     

Catalytic Synthesis of β-(Hetero)arylethylamines: Modern Strategies and Advances

β-(Hetero)arylethylamines appear in a myriad of pharmaceuticals due to their broad spectrum of biological properties, making them prime candidates for drug discovery. Conventional methods for their preparation often require engineered substrates that limit the flexibility of the synthetic routes and the diversity of compounds that can be accessed. Consequently, methods that provide rapid and versatile access to those scaffolds remain limited. To overcome these challenges, synthetic chemists have designed innovative and modular strategies to access the β-(hetero)arylethylamine motif, paving the way for their more extensive use in future pharmaceuticals. This review outlines recent progresses in the synthesis of (hetero)arylethylamines and emphasizes how these innovations have enabled new levels of molecular complexity, selectivity, and practicality.     

Ru3(CO)12-Catalyzed Modular Assembly of Hemilabile Ligands by C−H Activation of Phosphines with Isocyanates

Hemilabile ligands have been applied extensively in transition metal catalysis, but preparations of these molecules typically require multistep synthesis. Here, modular assembly of diverse phosphine-amide ligands, including related axially chiral compounds, is first reported through ruthenium-catalyzed C−H activation of phosphines with isocyanate directed by phosphorus(III) atoms. High reactivity and regioselectivity can be obtained by using a Ru₃(CO)₁₂ catalyst with a mono-N-protected amino acid ligand. This transformation significantly expands the pool of phosphine-amide ligands, some of which have shown excellent efficiency for asymmetric catalysis. More broadly, the discovery constitutes a proof of principle for facile construction of hemilabile ligands directly from the parent monodentate phosphines by C−H activation with ideal atom, step and redox economy. Several dinuclear ruthenium complexes were characterized by single-crystal X-ray diffraction analysis revealing the key mechanistic features of this transformation.     

Dual-Atomic-Site Catalysts for Molecular Oxygen Activation in Heterogeneous Thermo-/Electro-catalysis

Efficient molecular oxygen activation (MOA) is the key to environmentally friendly catalytic oxidation reactions. In the last decade, single-atomic-site catalysts (SASCs) with nearly 100 % atomic utilization and unique electronic structure have been widely investigated for MOA. However, the single active site makes the activation effect unsatisfactory and difficult to deal with complex catalytic reactions. Recently, dual-atomic-site catalysts (DASCs) have provided a new idea for the effective activation of molecular oxygen (O₂) due to more diverse active sites and synergetic interactions among adjacent atoms. In this review, we systematically summarized the recent research progress of DASCs for MOA in heterogeneous thermo- and electrocatalysis. Finally, we look forward to the challenges and application prospects in the construction of DASCs for MOA.     

Reversible Dihydrogen Activation and Catalytic H/D Exchange with Group 10 Heterometallic Complexes**

Reaction of a hexagonal planar palladium complex featuring a [PdMg₃H₃] core with H₂ is reversible and leads to the formation of a new [PdMg₂H₄] tetrahydride species alongside an equivalent of a magnesium hydride co-product [MgH]. While the reversibility of this process prevented isolation of [PdMg₂H₄], analogous [PtMg₂H₄] and [PtZn₂H₄] complexes could be isolated and characterised through independent syntheses. Computational analysis (DFT, AIM, NCIPlot) of the bonding in a series of heterometallic tetrahydride compounds (Ni–Pt; Mg and Zn) suggests that these complexes are best described as square planar with marginal metal-metal interactions; the strength of which increases slightly as group 10 is descended and increases from Mg to Zn. DFT calculations support a mechanism for H₂ activation involving a ligand-assisted oxidative addition to Pd. These findings were exploited to develop a catalytic protocol for H/D exchange into magnesium hydride and zinc hydride bonds.