Preparation of α-hydroxyphosphonates over phosphate catalysts

Catalysts based on natural phosphate (NP) are able to catalyze the synthesis of α-hydroxyphosphonates by reaction of dimethyl or diethyl phosphite with aldehydes and ketones at room temperature. This eco-friendly method is more efficient with modified phosphate, either impregnated with KF (KF/NP) or modified with sodium (Na/NP). Excellent yields (89–99%) were obtained with Na/NP in very short reaction times, 1–5 min in the case of aldehydes and 1–1.5 h in the case of ketones, a remarkable activity considering the very low surface area of the solid and the absence of solvent during the synthesis process. This catalyst was fully recoverable after calcination in four consecutive runs.