Three Reaction Channels with Signature Proton Transfers in the Ni(I)-Catalyzed Decomposition of Ethyl Acetate

The decomposition of ethyl acetate catalyzed by Ni­(I) has been investigated in the gas phase both experimentally and computationally. This approach allows us to determine what is the bare effect of the metal center in the catalytic process, without the intervention of environmental factors such as solvent, ligands, counterions, etc. This reaction is found to exhibit three competitive channels affording different products: ketene or ethanol, two units of acetaldehyde, and acetic acid or ethylene. Interestingly, each of these channels involves a characteristic hydrogen shift as the key step on the catalytic process: an inner-sphere H shift, an outer-sphere shift, and a peculiar orbital-like motion that merits careful characterization.