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~, R2 = CH2PI1 and CH2CMe3, 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 HC1 in dioxane to give a-hydroxy phosphonic acids. While direct methanolysis of the phosphonamides was unsuccessful, methylation of the phosphonic acids with diazomethane gave a-hydroxy dimethylphosphonates.

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The crystal structures of the racemate and the (S) enantiomer of (1-hydroxy-3-phenyl-2-propenyl) dimethylphosphonate, C11H15O4P, were determined by X-ray diffraction. The crystal density of the racemate was found to be 6.2% greater than the crystal density of the (S) enantiomer. In both crystal structures the molecules form chains by hydrogen bonding between the OH of one molecule and the P=O of another. Observed differences in atomic displacement between the two structures are discussed in view of the C—H...O interactions.

The crystal structure of the title compound, C21H42S3, comprises two independent pseudo-enantiomeric molecules, related by an approximate n-glide plane operation perpendicular to the b axis followed by a rotation

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