Synthesis of new fluorinated proline analogues from polyfluoroalkyl beta-ketoacetals and ethyl isocyanoacetate

The reaction of trifluoroaldol acetal and other polyfluoroalkyl β-ketoacetals with ethyl isocyanoacetate was applied for the preparation of hitherto unknown fluorinated amino acids, cis- and trans-3-CF₃/C₂F₅-prolines as well as trans-3-CF₂Br/CF₂Cl/CHF₂-3-hydroxyprolines.