methyl (2S,3S)-3-(tert-butoxy)-5-oxopyrrolidine-2-carboxylate

methyl (2S,3S)-3-(tert-butoxy)-5-methoxy-3,4-dihydro-2H-pyrrole-2-carboxylate

(2S,3S)-3-(tert-butoxy)-5-oxopyrrolidine-2-carboxylic acid

(7S,7aR)-7-(tert-butoxy)-3,3-dimethyltetrahydro-3H,5H-pyrrolo[1,2-c]oxazol-5-one

(S)-2-bromo-1-(4-(tert-butoxymethyl)-2,2-dimethyloxazolidin-3-yl)ethan-1-one