| Abstrakt: |
The stereodivergent synthesis of all four stereoisomers of diethyl 4-hydroxyphosphopipecolate from the commercial chiral building block ethyl (R)-4-cyano-3-hydroxybutanoate is described. Key steps in the synthesis of the target compounds involve the triethyl phosphite nucleophilic addition to chiral N -acyliminium ion easily obtained from (R)-4-hydroxypiperidin-2-one, giving diethyl (2 R ,4 R)- and (2 S ,4 R)-4-hydroxyphosphopipecolate diastereoisomers, easily separable by column chromatography followed by the 4-hydroxy epimerization through a sequential oxidation and highly diastereoselective reduction strategy, affording the diethyl (2 R ,4 S)- and (2 S ,4 S)-4-hydroxyphosphopipecolate, respectively, consistent with our recently found results. All synthesized compounds were thoroughly characterized. [ABSTRACT FROM AUTHOR] |
