<div> <p>A facile one-pot strategy for ¹³CN and ¹⁴CN exchange with aryl, heteroaryl, and vinyl nitriles using a Ni phosphine catalyst and BPh₃ is described. This late-stage carbon isotope exchange (CIE) strategy employs labeled Zn(CN)₂ to facilitate enrichment using the non-labeled parent compound as the starting material, eliminating <i>de novo</i> synthesis for precursor development. A broad substrate scope encompassing multiple pharmaceuticals is

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... sclosed, including the preparation of [¹⁴C]<a>belzutifan</a> to illustrate the exceptional functional group tolerance and utility of this labeling approach. Preliminary experimental and computational studies suggest the Lewis acid BPh₃ is not critical for the oxidative addition step and instead plays a role in facilitating CN exchange on Ni. This CIE method dramatically reduces the synthetic steps and radioactive waste involved in preparation of ¹⁴C labeled tracers for clinical development.</p> </div>