Deuteration of Aromatic Rings under Very Mild Conditions through Keto-Enamine Tautomeric Amplification

We have discovered a surprising, mild method for deuteration of select aromatic compounds that is facilitated by a keto-enamine tautomeric intermediate: The mechanism of the reaction has been studied using kinetics experiments and detailed computational analysis. It was found that a chain of water molecules has a substantial role in lowering the activation barrier to the tautomerization-enhanced deuteration reaction. Our results demonstrate that tautomeric forms of aromatic molecules can be exploited to bring about enhanced reactivity.