intramolecular aryl–phenyl scrambling reaction within palladium–DPPP–aryl complex (DPPP=1,3‐bis(diphenylphosphino)propane) ions was analyzed by state‐of‐the‐art tandem MS, including gas‐phase ion/molecule reactions. The Mizoroki–Heck cross‐coupling reaction was performed in the gasphase, and the intrinsic reactivity of important intermediates could be examined. Moreover, linear free‐energy correlations were