Asymmetric synthesis of β-amino acids by addition of chiral enolates to N-Acyloxyiminium ions and application for synthesis of optically active 5-substituted 8-methylindolizidines

Article abstract of DOI:10.1021/ol9905755

(Equation Presented) N-Acyloxyiminium species generated from nitrones with acyl halides are highly reactive and can undergo reaction with soft nucleophiles such as enolates. Optically active β-amino acid derivatives can be prepared using chiral enolates bearing chiral auxiliary. The usefulness of the present method is demonstrated by the enantioselective synthesis of (5R,8R,8aS)-5-cyano-8-methylindolizidine ((-)-7), which is a common key intermediate for 5-substituted 8-methylindolizidines.