K₃PO₄-Catalyzed Regiospecific Aminobromination of β-Nitrostyrene Derivatives with N-Bromoacetamide as Aminobrominating Agent

A very simple, efficient, and regiospecific protocol for aminobromination of a wide scope of β-nitrostyrene derivatives with N-bromoacetamide (NBA) as nitrogen/bromine sources has been developed by using K₃PO₄ as catalyst. The reaction proceeded smoothly and cleanly to give the bromoamines in good to excellent yields (78−99%) within 24 h in CH₂Cl₂ at room temperature without protection of inert gases. A possible mechanism involving a nucleophilic conjugate addition was proposed.