Reaction of N-Benzoyl-2-bromoglycine Methyl Ester With Deprotonated Nitroalkanes: Synthesis of β-Nitro and α,β-Dehydro Amino Acid Derivatives

N-Benzoyl-2-bromoglycine methyl ester (1) reacted with the alkyl nitronates (2a-e) to give the corresponding β-nitro amino acid derivatives (4a-e). Elimination reactions of (4a-d) afforded the α,β-dehydro amino acid derivatives (5a-d). Treatment of the β- nitrovaline derivative (4b) with tributyltin hydride gave the valine derivative (8). Reduction of the β- nitroalanine derivative (4a) gave the β- aminoalanine derivative (9), characterized by hydrolysis to 2,3- diaminopropionic acid hydrochloride.