Nickel-Catalyzed Reductive Arylation of <i>N</i> -Acyl Hemiaminals

<i>N</i>-Benzyl amides are important structural motifs in pharmaceuticals and natural products. The nucleophilic substitution reactions between aromatic nucleophiles and <i>N</i>-acyliminium ion precursors (<i>N</i>-acyl hemiaminal derivatives) represent one of the most common and powerful approaches. However, these protocols are typically limited by the scope of aromatic substrates or the requirement for air-sensitive reagents. Herein, we report a nickel-catalyzed reductive arylation reaction between <i>N</i>-acyl hemiaminals and readily available aryl halides, which enables the synthesis of a series of structurally diverse <i>N-</i>benzyl amide derivatives under mild conditions through simple operations. Mechanistic studies support a nickel-catalyzed cross-coupling pathway mediated by an <i>N</i>-acyliminium ion intermediate and exclude the participation of an <i>N</i>-acyl α-aminoalkyl radical.