The catalytic functionalization of silicon–hydrogen bonds by means of the insertion of carbene units :CHCO₂Et from ethyl diazoacetate (EDA) has been achieved using a silver-based catalyst, constituting the first example of this metal to promote this transformation. Competition experiments have revealed that the relative reactivity of substituted silanes depends on the bond dissociation energy of the Si–H bond (tertiary > secondary > primary for ethyl substituted). In the presence of bulky substituents such order reverts to secondary > primary ≈ tertiary (for phenyl substituted). Screening with other diazo compounds has shown that N₂C(Ph)CO₂Et displays similar reactivity to that of EDA, whereas other N₂C(R)CO₂Et (R = Me, CO₂Et) gave lower conversions.