Enantiopure synthesis of side chain-modified α-amino acids and 5-cis-alkylprolines
Amar R Mohite1, Ramakrishna G Bhat
1Department of Chemistry, Mendeleev Block, Indian Institute of Science Education and Research, Pune, Maharashtra, 411008, India.
Abstract:
A short, concise synthesis of enantiopure, side chain-modified α-amino acids such as 4-oxo-L-norvaline, 6-oxo-L-homonorleucine, and 5-cis-alkyl prolines is described. Knoevenagel condensation of l-aminocarboxylate-derived β-ketoesters with aldehydes followed by reductive decarboxylation results in unnatural α-amino acids in good yield. A fluorescent amino acid is synthesized using a similar protocol. These studies show that aminocarboxylate-derived β-ketoesters are very useful intermediates and the method employed is both general and practical for the preparation of γ(δ)-oxo α-amino acids and alkylprolines.
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