Phosphorus‐Modified Ru ₂ P Enables the Selective Deuteriation of Amino Acids

Regioselective deuteration plays a crucial role in advancing deuterated drug synthesis and protein dynamics studies. Thus, the development of catalysts enabling regionally selective deuteration is highly desirable. In this work, Ru 2 P nanoparticles were supported on nitrogen‐doped porous carbon derived from chitosan pyrolysis for the site‐selective α‐deuteration of valine. The distinct chemical environment surrounding ruthenium enables oriented adsorption of amino acids, while the relatively weak interaction between the substrate and metal facilitates selective α‐hydrogen activation and subsequent substitution. Under mild reaction conditions with D 2 O as the deuterium source, the catalyst achieved high levels of isotopic incorporation at the α‐position (93.3% D) with great regioselectivity (99%) and excellent recyclability (85% D incorporation at the α‐position with regioselectivity of 95% after 10 cycles). This catalytic strategy demonstrates broad potential for the synthesis of diverse site‐selectively deuterated organic molecules.