Preparation of α-amino-carboxylic acid derivatives via diastereoselective reactions of glycine enolate equivalents

Abstract

Protected glycine analogues tethered to an imidazolidinone auxiliary undergo diastereoselective alkylation and acylation reactions in moderate to good yields (9–91%) with high levels of stereocontrol (generally >95% de). Subsequent alkylation of these derivatives has been demonstrated for the production of non-racemic α,α-disubstituted amino acid precursors. Diastereoselective aldol reactions are also found to proceed with good yields and excellent stereocontrol (62–84%, 93–95% de). Chiral auxiliary cleavage and hydrogenolysis of these adducts affords the β-hydroxy-α-amino acid derivatives with no observed erosion of optical purity.