1. Insights into the Mechanism, Regio-/Diastereoselectivities and Ligand Role of Nickel-Initiated [3+2] Cycloadditions between Vinylcyclopropane and N-Tosylbenzaldimine
- Author
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Weihua Mu, Lin Zhu, Shuya Xia, Xue Tan, Liangfei Duan, Guanghao Meng, and Guo Liu
- Subjects
nickel ,catalysis ,vinylcyclopropane (VCP) ,[3+2] cycloaddition ,mechanism ,DFT ,Chemical technology ,TP1-1185 ,Chemistry ,QD1-999 - Abstract
Density functional theory (DFT) was employed to explore the reaction mechanism, regio- and diastereoselectivities of nickel-initiated [3+2] cycloaddition between vinylcyclopropane (VCP) and N-tosylbenzaldimine assisted by phosphine ligands. Four different binding modes of the nickel center to VCP substrate were explored during the ring-opening of VCP, among which the C,C_anti and C,C_syn modes were verified to be the most accessible ones. Further explorations about four different phosphine ligand-assisted reactions based on the two most probable binding modes show that the difference in binding mode of bi- and monodentate phosphine ligands can vary the optimal reaction pathway, especially in the [3+2] cycloaddition process between the ring-opened intermediate and N-tosylbenzaldimine. The formation of C–C and C–N bonds between N-tosylbenzaldimine and the ring-opened intermediate through [3+2] cycloaddition is found to be stepwise, with the former acting as the rate-determining step (RDS) in most cases. Computed free energy barriers of RDS transition states on the optimal path I or II not only give out good predictions for reaction rates and half-lives, but also provide reasonable explanations for the major generation of cis-pyrrolidine. Noncovalent interaction analyses of key stationary points suggest the rate is influenced by both electronic effects and steric hindrance, while the diastereoselectivity is mainly controlled by electronic effects.
- Published
- 2024
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