A facile synthesis of aminomethylene bisphosphonates catalyzed by ytterbium perfluorooctanoate under ionic liquid condition

Three-component reactions of amines, triethylorthoformate and diethyl phosphite are efficiently catalyzed by ytterbium perfluorooctanoate [Yb(PFO)3] in 1-butyl-3-methylimidazolium chloride ([bmim][Cl]) ionic liquid, giving the corresponding aminomethylene bisphosphonates in good yields. The catalyst can be recovered and reused for several times without any significant loss of activity.