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 diamide s in THF solution gave a-hydroxy phosphonamides in good yield. The dia stereoselectivity was strongly dependent upon the diamide used and ran ged 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 studie d. Diamide 2b consistently gave good selectivities, whereas diamide 2a was only moderately selective. Aromatic, aliphatic, and unsaturated a ldehydes are tolerated under the reaction conditions. The phosphonamid es were hydrolyzed with aqueous HCl in dioxane to give a-hydroxy phosp honic acids. While direct methanolysis of the phosphonamides was unsuc cessful, methylation of the phosphonic acids with diazomethane gave al pha-hydroxy dimethylphosphonates.