REACTIONS OF CHIRAL PHOSPHORUS-ACID DIAMIDES - THE ASYMMETRIC-SYNTHESIS OF CHIRAL ALPHA-HYDROXY PHOSPHONAMIDES, PHOSPHONATES, AND PHOSPHONIC-ACIDS

Addition of aldehydes to the anions of chiral phosphorous acid diamides in THF solution gave a-hydroxy phosphonamides in good yield. The diastereoselectivity was strongly dependent upon the diamide used and ranged from poor to good. The phosphorous acid diamides 2a and 2b (R(1) = -(CH2)4-,R(2) = CH(2)Ph and CH(2)CMe(3), respectively) gave the best selectivity, and their reactions with a range of aldehydes were studied. Diamide 2b consistently gave good selectivities, whereas diamide 2a was only moderately selective. Aromatic, aliphatic, and unsaturated aldehydes are tolerated under the reaction conditions. The phosphonamides were hydrolyzed with aqueous HCl in dioxane to give a-hydroxy phosphonic acids. While direct methanolysis of the phosphonamides was unsuccessful, methylation of the phosphonic acids with diazomethane gave alpha-hydroxy dimethylphosphonates.