The mechanism of oxidative addition of Pd(0) to Si–H bonds: electronic effects, reaction mechanism, and hydrosilylation

order in silane. Formed complexes exhibit temperature-dependent intramolecular H/Si ligand exchange on the NMR timescale, allowing determination of the energetic barrier to reversible oxidative addition. Taken together, these results give unique insight into the individual steps of oxidative addition and suggest the initial formation of a σ-complex intermediate to be rate-limiting. The insight gained from these mechanistic studies was applied to hydrosilylation of alkynes, which shows parallel trends in the effect of the silanes' substituents. Importantly, this work highlights the relevance of in-depth mechanistic studies of fundamental steps to catalysis.