A Novel Method for the Separation of Bis(α-hydroxyalkyl)phosphinic Acid Diastereoisomers via Formation of Novel Cyclic Phosphinic Acids

The reaction of aromatic and aliphatic aldehydes with hypophosphorus acid under microwave irradiation was examined. The reaction gave a mixture of a racemic pair of bis(α-hydroxyalkyl)phosphinic acids and acetal derivatives from the corresponding bis(α-hydroxyalkyl)phosphinic acids of meso-stereochemistry in good yield. The difference in solubility in organic solvents due to polarity allowed us to readily separate these compounds. This method constitutes an easy, rapid, and good-yielding preparation and separation of bis(α-hydroxyalkyl) phosphinic acid diastereoisomers from simple starting materials using microwave irradiation.