Direct Aminophosphonylation of aldehydes catalyzed by cyclopentadienyl ruthenium(II) complexes

This work reports a novel method for the direct aminophosphonylation of aldehydes catalyzed by cyclopentadienyl ruthenium(II) complexes. The system HP(O)(OEt)(2)/[CpRu(PPh3)(2)Cl] was very efficient for the aminophosphonylation of aldehydes with primary and secondary amines, producing the corresponding alpha-aminophosphonates in good to excellent yields. This novel method has several advantages including the use of a small amount of catalyst (0.5 mol%), high chemoselectivity, solvent-free conditions and application of the catalyst [CpRu(PPh3)(2)Cl] for at least 12 cycles with excellent activity. (C) 2018 Elsevier Ltd. All rights reserved.