235084-93-2

Upstream product

• 321851-63-2 (4R,5S)-3-{(2S)-2-[(2S)-1-benzyloxycarbonylpyrrolidin-2-yl]propionyl}-4-methyl-5-phenyl-2-oxazolidinone 
• 501-53-1 benzyl chloroformate 

Downstream Products

• 321851-65-4 diethyl (2R)-2-[(2S)-1-benzyloxycarbonylpyrrolidin-2-yl]propylmalonate 
• 235084-94-3 ethyl (4R)-4-[(2S)-1-benzyloxycarbonylpyrrolidin-2-yl]pentanoate 
• 321851-66-5 (2S)-1-benzyloxycarbonyl-2-[(2R)-5,5-dimethoxypent-2-yl]pyrrolidine 
• 321851-64-3 (2S)-1-benzyloxycarbonyl-[(1S)-2-bromo-1-methylethyl]pyrrolidine 

Relevant academic research and scientific papers

Asymmetric synthesis of β-amino acids by addition of chiral enolates to nitrones via N-acyloxyiminium ions

N-Acyloxyiminium ions, generated by the reaction of nitrones with acyl halides, are highly reactive species and undergo facile reaction with a wide range of nucleophiles, such as ketene silyl acetals, titanium(IV) and boron enolates, hydrido- and allyltin(IV) reagents, and alkynyltitanium(IV) reagents, to give α-substituted amine derivatives. Optically active β-amino acids can be prepared by the reaction of N-acyloxyiminium ions with both boron and titanium(IV) enolates bearing chiral auxiliaries. Reversal of diastereoselectivity was observed by the reactions of the boron and titanium(IV) enolates. Using these reactions, all of the four stereoisomers of α-methyl-β-phenylalanines, for example, can be prepared highly diastereoselectively. Cyclic N-acyloxyiminium ions are useful for the asymmetric synthesis of pyrrolidine and piperidine alkaloids; (5R,8R,8aS)-5-cyano-8-methylindolizidine, which is a common key intermediate for synthesis of 5-substituted 8-methylindolizidines, was prepared selectively.

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

(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.