Rh/SPO-WudaPhos-Catalyzed Asymmetric Hydrogenation of alpha-Substituted Ethenylphosphonic Acids via Noncovalent Ion-Pair Interaction

Asymmetric hydrogenation of alpha-substituted ethenylphosphonic acids has been successfully achieved by Rh/ferrocenyl chiral bisphosphor ligand, (SPO-Wudaphos) through noncovalent ion-pair interaction between the substrate and catalyst tinder mild,reaction conditions without base. A series Of chiral phosphonic acids were obtained with excellent results (up to 98% ee, >99% conversion, 2000 TON). Moreover, the Control experiments showed that the noncovalent ion-pair interaction, was critical in this asymmetric hydrogenation.