Efficient C−H/C−D Exchange Reaction\non the Alkyl Side Chain of Aromatic\nCompounds Using Heterogeneous Pd/C\nin D<sub>2</sub>O

An efficient and extensive deuterium incorporation using heterogeneous Pd/C−D₂O−H₂ system into many different types of unactivated C−H\nbond positions was developed. The present method provides a deuterium gas-free, totally catalytic, and post-synthetic deuterium labeling\nmethod in D₂O media.