While DFT-computed barrier heights appear to be able to predict the regioselectivities this has really only been tested for a handful of systems. The reason is that it is difficult to automate the location of transition states (TSs) in a reliable fashion. We noticed that the relative energies of the post-insertion complexes, computed by Bäcktorp and Norrby, correlate reasonably well with the respective relative barrier heights (Figure ). These relative energies are much easier to compute in an automated fashion and we decided to test whether this correlation holds in general. We present a fully automated QM-based workflow for determining the regioselectivity of intermolecular Heck reactions that is based on calculated relative energies of these post-insertion complexes following the carbopalladation step. The method applies to cross-couplings of monosubstituted alkenes with aryl/vinyl halides (Cl, Br, or I) or triflates in the presence of a base and a palladium (Pd) catalyst with monodentate triphenylphosphine (PPh 3 ) ligands to form branched (α) and/or linear (β) disubstituted alkenes. In fact, the workflow can handle intramolecular Heck reactions, but we will focus on the intermolecular Heck reactions and test the approach on several thousands of such reaction outcomes.