New synthetic routes to α-amino acids and γ-oxygenated α-amino acids.: Reductive denitration and oxidative transformations of γ-nitro-α-amino acids

Transformation of gamma-nitro-alpha-amino acid derivatives into alpha-amino acids by reductive denitration, into the gamma-oxo-alpha-amino acids by ozonolysis of the corresponding amino acid ester nitronate derivatives, and into gamma-hydroxy-alpha-amino acid derivatives by subsequent reduction of the oxo functionality, can be achieved in good yields. As the gamma-nitro-alpha-amino acid derivatives are prepared from N,O-protected dehydroalanines derivable from the corresponding alanine, serine and cysteine derivatives by specific routes, the overall procedures provide a means for selective conversion of these simple alpha-amino acids into more complex ones.