Highly diastereoselactive synthesis of chimeras of proline and glutamate

Azomethine ylides have been generated from aromatic aldimines of α‐amino acid methyl esters under treatment with LiBr/Et₃N and trapped with tert‐butyl acrylate yielding racemic orthogonally protected cis‐5‐arylpyrrolidine‐2,4‐dicarboxylates regio‐ and stereo‐selectively in high yields. Subsequent N‐methylation and deprotection of 4‐carboxylic group of cycloaddition products led to novel prolineglutamate cis‐chimeras with substituents at 2 and 5 positions of pyrrolidine scaffold.