2025/06/23 by Ivo H. Lindenmaier, Robert C. Richter, Marius Schier +2 · 1 voice
Chemistry · Pharmacology, Toxicology and Pharmaceutics · #Catalytic Cross-Coupling Reactions #Fluorine in Organic Chemistry #Sulfur-Based Synthesis Techniques
paper · pdf · doi:10.26434/chemrxiv-2025-51g67
openalex publication_date 2025/06/23 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/14
We report a nickel-catalyzed cross-coupling between aryl (pseudo-)halides and thiols under mechanochemical conditions. The reaction tolerated both alkyl and aryl thiols and required lower catalyst loading than the same catalyst under homogenous conditions. Moreover, the reaction can be set up under air, greatly simplifying and shortening reaction setup. Notably, trialkyl amines proved most efficient as a base under mechanochemical conditions. This class of bases has been rarely used in C–S cross-couplings before. The applicability of this system was demonstrated on numerous examples, including compounds relevant to materials science and pharmaceuticals. Mechanistic studies revealed that the reaction is driven by thermal energy produced by the mixer mill, while no evidence for involvement of mechanical force in the mechanism could be obtained. Using neat NMR and DSC techniques, it could be shown that the catalyst is initially deactivated by excess thiol, forming a mixture of nickel(hydrido)(thiolate) species. Upon reduction by zinc, the active catalyst is formed, able to engage in a Ni(0)/Ni(II) catalytic cycle.