A nickel-catalyzed intramolecular C-N coupling reaction via SO2 extrusion is presented. The use of a catalytic amount of BPh3 allows the transformation to take place under much milder conditions (60 °C) than previously reported C-N coupling reactions by CO or CO2 extrusion (160-180 °C). In addition, this method displays good functional group tolerance and versatility, as it can be applied to the synthesis of dialkyl aryl amines, alkyl diaryl amines, and triaryl amines. The robustness of the desulfitative C-N coupling is demonstrated by three high-yielding gram-scale reactions.
Liu, J., Jia, X., Chen, X., Sun, H., Li, Y., Kramer, S., & Lian, Z. (2020). Nickel-Catalyzed Intramolecular Desulfitative C-N Coupling: A Synthesis of Aromatic Amines. Journal of organic chemistry, 85(8), 5702-5711. https://doi.org/10.1021/acs.joc.0c00009