AI Article Synopsis
- The palladium-catalyzed reaction of aromatic amides with maleimides leads to the formation of a product through double C-H bond activation at benzylic and meta positions.
- Computational studies reveal that the reaction mechanism involves a series of steps: formation of a palladacycle, maleimide insertion, and activation of the meta C-H bond, culminating in a product through reductive elimination.
- Energy analysis indicates that while ortho C-H activation is energetically favored, it is not productive, and the nature of the directing group, particularly the strong Pd-S bond from 2-thiomethylphenyl, plays a crucial role in site selectivity and reaction efficiency.
Article Abstract
The palladium-catalyzed reaction of aromatic amides with maleimides results in the formation of a double C-H bond activation product, which occurs at both the benzylic and meta positions. Computational chemistry studies suggest that the first C-H bond activation unfolds via a six-membered palladacycle, maleimide insertion, protonation of the Pd-N bond, and then activation of the meta C-H bond. The process concludes with reductive elimination, producing an annulation product. The energy decomposition analysis (EDA) showed that the deformation energy favors the ortho C-H bond activation process. However, this route is non-productive. The interaction energy controls the site where the maleimide is inserted into the Pd-C(sp ) bond, which determines its site selectivity. The energetic span model indicates that the meta C-H bond activation step is the one that determines the turnover frequency. Regarding the directing group, it has been concluded that the strong Pd-S bonding and the destabilizing effect of the deformation energy allow the 2-thiomethylphenyl to function effectively as a directing group.
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