“…To assess this hypothesis, we have conducted a combined computational and experimental study of the oxidative addition rate and site selectivity for substituted halopyridines to L 2 Pd(0), using Pd(PCy 3 ) 2 as an exemplar . In a concurrent and complementary study, Neufeldt and co-workers further establish the interplay between Pd speciation, ligand identity, and orbital symmetry in determining the mechanism of oxidative addition for unsubstituted phenyl–X and pyridyl–X substrates (X = F, Cl, Br, I, OTf) …”