Reversal of Diastereoselectivity in a Masked Acyl Cyanide (MAC) Reaction: Synthesis of Protected <i>erythro</i>-β-Hydroxyaspartate Derivatives

Using Garner’s aldehyde as a substrate, one-pot MAC hydroxyhomologation reactions proceeded in good yields and with <i>anti</i> selectivity for the first time (dr up to 9:1). The products were used to prepare a panel of protected derivatives of <i>erythro</i>-β-hydroxyaspartic acid and <i>erythro</i>-β-hydroxyasparagine as single enantiomers in a few steps.