for the following products
(aS,3S)-a-[(tert-butyloxycarbonyl)amino]-2-oxo-3-pyrrolidinepropanoic acid methyl ester | (S)-Methyl 2-((tert-butoxycarbonyl)amino)-3-((S)-2-oxopyrrolidin-3-yl)propanoate and Methyl (S)-2-(Boc-amino)-3-[(S)-2-oxo-3-pyrrolidinyl]propanoate
