Computational Exploration of Dirhodium Complex-Catalyzed Selective Intermolecular Amination of Tertiary vs. Benzylic C-H Bonds.
Xing-Xing SuXia-He ChenDe-Bo DingYuan-Bin SheYun-Fang YangPublished in: Molecules (Basel, Switzerland) (2023)
The mechanism and origins of site-selectivity of Rh 2 ( S -tfpttl) 4 -catalyzed C( sp 3 )-H bond aminations were studied using density functional theory (DFT) calculations. The synergistic combination of the dirhodium complex Rh 2 ( S -tfpttl) 4 with tert -butylphenol sulfamate TBPhsNH 2 composes a pocket that can access both tertiary and benzylic C-H bonds. The nonactivated tertiary C-H bond was selectively aminated in the presence of an electronically activated benzylic C-H bond. Both singlet and triplet energy surfaces were investigated in this study. The computational results suggest that the triplet stepwise pathway is more favorable than the singlet concerted pathway. In the hydrogen atom abstraction by Rh-nitrene species, which is the rate- and site-selectivity-determining step, there is an attractive π-π stacking interaction between the phenyl group of the substrate and the phthalimido group of the ligand in the tertiary C-H activation transition structure. By contrast, such attractive interaction is absent in the benzylic C-H amination transition structure. Therefore, the DFT computational results clearly demonstrate how the synergistic combination of the dirhodium complex with sulfamate overrides the intrinsic preference for benzylic C-H amination to achieve the amination of the nonactivated tertiary C-H bond.
Keyphrases
- density functional theory
- molecular dynamics
- energy transfer
- transition metal
- room temperature
- magnetic resonance
- cancer therapy
- molecular docking
- magnetic resonance imaging
- drug delivery
- mass spectrometry
- molecular dynamics simulations
- staphylococcus aureus
- structural basis
- high resolution
- atomic force microscopy
- amino acid
- single molecule