As can be seen in Table , in this palladium catalysed system, different exchange and correlation functionals only cause minor influence to the results. In this case, the most popular and welldeveloped functional B3LYP functional v was selected for further calculation in this project. At first, geometry of all generated intermediates was optimized over 5 iterations . Then the structures having higher energy by a value of 10 $%&' • )*' !" as compared to the least energy intermediate were crossed out, the remaining structure were then fully optimized and thermochemistry applied . The geometry of the structures was considered stable and correct only if no negative vibrational frequencies were found after calculating force constants and vibrational frequencies. Moreover, for the unstable intermediates, the algorithm would automatically generate another structure based on the former calculation as a starting point for further optimization.