A GENERAL SYNTHETIC APPROACH TO ALPHA-HYDROXY PHOSPHORYL COMPOUNDS

A general synthetic way for the preparation of a large variety of cc-h ydroxy phosphoryl compounds is here reported. In our approach, trialky l phosphite is added in equimolar amount, at room temperature and unde r strong acidic conditions (HCl gas), to the corresponding carbonyl co mpound dissolved in anhydrous dioxane. The reaction is quite exothermi c and cooling is often needed; 10-15 min reaction time is sufficient i n order to assure almost quantitative yields in the desired product, w hich can be easily isolated as a white pure solid by concentration of the reaction mixture. The reaction works in an excellent way with all kind of aliphatic, aromatic and heteroaromatic aldehydes. The alpha-hy droxy phosphonates obtained were fully characterized by H-1- and P-31- NMR, by FAB-MS and IR spectroscopy. When o-carboxybenzaldehyde was use d as a reagent, cyclic dialkyl phthalide-3-phosphonates were obtained in very good yields (greater than or equal to 90%).