1,3-Dipolar cycloaddition reactions of ester-stabilized azomethine ylides with acrolein: a one-pot regio- and stereoselective synthesis of N-substituted 4-formyl-5-vinyl proline carboxylates

Reaction of N-alkylated glycine esters with excess acrolein in the presence of acid, followed by treatment with triethylamine, provided N-substituted 4-formyl-5-vinyl proline carboxylates in good yields with high regio- and stereoselectivity.