Sequential Catalysis for the Production of Sterically Hindered Amines: Ru(II)-Catalyzed C–H Bond Activation and Hydrosilylation of Imines

Sequential ruthenium(II) catalyzed reactions for the production of secondary amines from simple imines are reported. They involve Ru(II)-acetate based catalytic systems for C–H Bond activation/diarylation of simple imines with aryl bromides followed by [RuCl₂(arene)]₂hydrosilylation of diarylated imines. The direct diarylation of aldimines can be profitably produced by Ru(II) catalytic systems in the presence of both acetate and PPh₃ ligands. By contrast, PPh₃ additive disfavors diarylation of ketimines that is achieved with [Ru(OAc)₂(p-cymene)] alone. The catalytic hydrosilylation of the resulting imines was simply performed with H₂SiPh₂ in the presence of [RuCl₂(arene)]₂ catalyst at room temperature leading to overall yield of 70–86% of secondary amines


ACS Catalysis, 2011, 1257.