syn-Selective boron mediated aldol condensations for the asymmetric synthesis of β-hydroxy-α-amino acids

Imidazolidinone-bound glycine enolate derivatives have been shown to undergo aldol condensation with aromatic and aliphatic aldehydes in good yields and with excellent stereocontrol (62–84%, 93–95% d.e.). Removal of the pendant imidazolidinone auxiliary and hydrogenolysis affords the β-hydroxy-α-amino acid derivatives.