Abstract: | The regioselectivity of the NHC‐Pd catalyzed Heck coupling reaction between phenyl bromide and styrene has been investigated using the density functional theory, wave‐function (WF)‐based methods and two different sizes of model ligands. In addition to the WF methods, the TPSS‐D3, B97X‐D, BP86‐D3, and M06‐L density functionals were reliable approaches to be applied, independently of the basis set. Moreover, the NCI analysis showed that weak interactions are important forces to be taken into account when exploring the regioselectivity of this reaction, mainly when a crowded NHC ligand is present. © 2017 Wiley Periodicals, Inc. |