Zirconium(IV) Compounds As Efficient Catalysts for Synthesis of α-Aminophosphonates

Zirconium(IV) compounds are reported as excellent catalysts for a three-component one-pot reaction of an amine, an aldehyde or a ketone, and a di/trialkyl/aryl phosphite to form α-aminophosphonates under solvent-free conditions at rt. Among the various zirconium compounds, ZrOCl₂·8H₂O and ZrO(ClO₄)₂·6H₂O were most effective. The reactions were faster with dialkyl/diaryl phosphites than with trialkyl/triaryl phosphites. No O−Me cleavage occurs with aryl methyl ether and methyl ester groups. α,β-Unsaturated carbonyl moiety does not undergo conjugate addition with the phorphorous moiety.