for the following products
(3S,5S)-tert-Butyl 3-isopropyl-5-((2S,4S)-4-isopropyl-5-oxotetrahydrofuran-2-yl)-2-oxopyrrolidine-1-carboxylate | Tert-butyl (3S,5S)-2-oxo-5-[(2S,4S)-5-oxo-4-propan-2-yloxolan-2-yl]-3-propan-2-ylpyrrolidine-1-carboxylate and (3S,5S)-3-Isopropyl-5-((2S,4S)-4-isopropyl-5-oxotetrahydro-furan-2-yl)-2-oxopyrrolidine-1-carboxylic acid tert-butyl ester
