A series of phosphonamide-based hydroxamate derivatives were synthesized, and the inhibitory activities were evaluated against various metalloproteinases in order to clarify its selectivity profile. Among the four diastereomeric isomers resulting from the chirality at the C- 3 and P atoms, the compound with a (R, R)-configuration both at the C-3 position and the phosphorus atom was found to be potently active, while the other diastereomeric isomers ...