DFT investigates the mechanisms of cross-dehydrogenative coupling between heterocycles and acetonitrile

Abstract

The mechanisms between CH₃CN and 1,3-dimethyl-1H-indole, initiated by DCP (dicumyl peroxide), have been studied with the B3LYP-D3 method with def2TZVP basis set for all atoms, and the SMD model was applied to simulate the solvent of acetonitrile. The computational results show that the homolytic process of DCP, catalysed by CuCl or CuI, can decrease the energy barrier, and the recycle procedure of Cu catalyst has been described. Then the Csp³-H activation of CH₃CN has been investigated. The introduction of the cyano group is an anti-Markovnikov reaction and region-selectivity would be fulfilled. Localised orbital bonding analysis, localised orbital locator (LOL) isosurfaces, and electron spin density isosurface graphs could be used to interpret the phenomena. The results could provide valuable insights into these types of interactions and related ones.

Highlights

• The homolytic mechanisms of DCP catalyzed by CuCl or CuI are proposed.

• The anti-Markovnikov's reaction between 1,3-dimethyl-1H-indole and free radical is investigated.

• Localized orbital bonding analysis, localized orbital locator (LOL) isosurfaces and electron spin density isosurface graphs have been used to interpret the phenomena.

GRAPHICAL ABSTRACT

KEYWORDS:

• CH₃CN
• Csp³-H activation
• DFT
• 1,3-dimethyl-1H-indole
• DCP

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supporting information

The cartesian coordinates of all the transition states and the energies of all structures.

Additional information

Funding

This work was supported by the Natural Science Foundation of Sichuan Province [grant number 2022NSFSC0629]; Natural Science Foundation of Shandong Province of China [grant number ZR2021MB107].