Mechanistic Insights into the Nickel-Catalyzed Cross-Coupling Reaction of Benzaldehyde with Benzyl Alcohol via C–H Activation: A Theoretical Investigation

Origins of regioselectivity in Ni-catalyzed hydrofunctionalization of alkenes via ligand-to-ligand hydrogen transfer mechanism

The origins of regioselectivity in Ni-catalyzed alkene hydrofunctionalizations were computationally investigated by using energy decomposition analysis. The results indicate the Markovnikov selectivity with aryl-substituted alkenes is favored due to the stabilizing charge transfer effect, and the anti-Markovnikov selectivity with alkyl-substituted alkenes is favored because of the destabilizing Pauli repulsion effect.

Insights into the nucleophilic substitution of pyridine at an unsaturated carbon center

Bimolecular nucleophilic substitution (S_N2) is a fundamental reaction that has been widely studied. So far, the nucleophiles are mainly anionic species in S_N2 reactions. In this study, we use density functional theory calculations to assess the mechanisms of substitution of carbonyl, imidoyl, and vinyl compounds with a neutral nucleophile, pyridine. Charge decomposition analysis is performed to explore the main components of the transition state's LUMO. For reactions of imidoyl or carbonyl compounds with pyridine or Cl⁻, the LUMOs of the transition states are composed of mixed orbitals originating from the nucleophile and the substrate. Considering the unique mixed nature of the orbitals, the reaction mode is termed S_Nm (m means mix). Moreover, the main components of the transition state's LUMO are pure σ*_C–Cl MO in the reactions of H₂C Created by potrace 1.16, written by Peter Selinger 2001-2019 ]]> CHCl with pyridine or Cl⁻. Computations were also performed for RYCHX substrates with different X and Y groups (X= Cl⁻, Br⁻, or F⁻; Y = O, N, or C).

The nucleophilic substitution of carbonyl, imidoyl, and vinyl carbon centers with pyridine or halides is investigated in this paper.

DFT study of Ni/NHC-catalyzed C–H alkylation of fluoroarenes with alkenes to synthesize fluorotetralins: mechanism, chemoselectivity of C–H vs. C–F bond activation, and regio- and enantioselectivities of C–H bond activation

DFT calculations clarified the mechanism of Ni/NHC-catalyzed C–H alkylation of alkene tethered fluoroarene and rationalized enantio-, regio- and chemoselectivities.

Enhancement of the Catalytic Activities of Heteronuclear Bimetallic Cations for the C-H Bond Activation of Cyclohexane

Heterometallic cations NiCu⁺ and CoNi⁺ can easily induce triple dehydrogenation of cyclohexane with high yield, and monometallic cations Ni⁺ and Co⁺ only give rise to double dehydrogenation with low yield. Reaction mechanisms of the six C-H bond activations for cyclohexane are systematically investigated by comparing the difference between bimetallic cations and monometallic ones. Fragment molecular orbital analysis clearly indicates that charge transfer (CT) occurs from the occupied interacting orbital of the metallic cation to the σ*-antibonding orbital of the first, third, and fifth activated C-H bonds in transition states. The synergistic effects of heteronuclear bimetallic cations result in the destabilization of the occupied interacting orbital in bimetallic cations, which raise the reactivity of bimetallic cations and enhance the CT between catalysts and substrates. Contrary to the absence of the third dehydrogenation product in the mononuclear metallic cation catalytic reaction, a significant amount of the third dehydrogenation product is observed in the presence of heteronuclear cations (NiCu⁺ and CoNi⁺). π back-bonding between Ni of heteronuclear metallic cations and the substrate cyclohexadiene plays an essential role in lowering the energies of transition states, which accelerate the third dehydrogenation. The reasons why heteronuclear bimetallic cations are more reactive than monometallic ones are discussed in detail.