Asymmetric Synthesis of β-Phosphono Malonates via Fe2O3-Mediated Phospha-Michael Addition to Knoevenagel Acceptors

[reaction: see text]. The first asymmetric P-C bond formation under heterogeneous conditions was achieved via a Fe2O3-mediated conjugate addition of a chiral phosphite to alkylidene malonates. The easy cleavage of the chiral auxiliary from the addition products leads to optically active beta-substituted beta-phosphono malonates in good yields and high enantiomeric excesses.