Rapid Methylthiolation of (Hetero)Aryl Halides at Room Temperature Using Sodium Thiomethoxide via Palladium‐Catalysis

We report a palladium-catalyzed strategy for the efficient thiomethylation of (hetero)aryl halides using sodium thiomethoxide (MeSNa) under mild conditions (25°C). This work introduces, for the first time, a room-temperature protocol for converting aryl and heteroaryl iodides into their corresponding thiomethylated products, enabled by the aminobiphenyl palladacycle precatalyst Pd-G3-XantPhos. The high reactivity of the in situ-generated Pd(0) catalyst allows for the selective introduction of the thiomethyl group into a broad range of substrates, including (hetero)aromatic compounds, bioactive molecules, drugs, peptides, and proteins. The method is fast, robust, and scalable, with excellent functional group tolerance and compatibility with aqueous environments. Additionally, it can be applied to methyl isotope-labeling, further expanding its utility.