Sonogashira Cross-Coupling of Aryl Ammonium Salts by Selective C–N Activation Catalyzed by Air- and Moisture-Stable, Highly Active [Pd(NHC)(3-CF₃-An)Cl₂] (An = Aniline) Precatalysts
2022
Lei, Peng | Wang, Yibo | Zhang, Caixia | Hu, Yuge | Feng, Juntao | Ma, Zhiqing | Liu, Xili | Szostak, Roman | Szostak, Michal
We report the Sonogashira cross-coupling of aryl ammonium salts catalyzed by air- and moisture-stable [Pd(NHC)(3-CF₃-An)Cl₂] (An = aniline). This highly active Pd(II)–NHC complex features broad scope and excellent C–N activation selectivity in the challenging alkynylative cross-coupling of aryl ammonium salts. Full structural characterization and computational studies demonstrate the effect of pyridine to aniline replacement as highly effective stabilizing ancillary ligand in well-defined Pd(II)–NHCs. Considering the high reactivity and the recent commercialization of [Pd(NHC)(3-CF₃-An)Cl₂] (Millipore Sigma, no. 915165), this catalyst represents an attractive approach to the activation of C–N bonds of broad synthetic interest.
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