We also considered that rate-limiting silane pre-activation through reaction with EtOH could be a plausible pathway to explain the presence of only silane and not iron in the rate law of the PhSiH3 system. Specifically, formation of the more active alkoxysilane species, PhSi(OEt)H2, from PhSiH3 could be catalyzed by ethoxide from solvent autoionization or by EtOH directly. However, we were able to rule out this hypothesis by monitoring a solution of PhSiH3 in EtOD by 1 H NMR spectroscopy over 10 h, during which we observed no detectable formation of new compounds. Therefore, reaction of silane with solvent is an unlikely rate determining step.