α-amino ester. Treatment of the oxime derivative prepared from methyl 5-bromo-2-oxopentanoate with the trialkylzincate gave an α-alkyl proline derivative via the addition reaction followed by the intramolecular attack upon a bromine-bearing carbon. The reaction of ethyl 4-oxo-2-pentynoate with hydroxylamine formed an isoxazole derivative by way of the intramolecular attack of an in situ-generated oxime