methyl (2R,3S,4R)-3-((tert-butyldimethylsilyl)oxy)-2-((S)-1-hydroxy-2-methylallyl)-1-(4-methoxybenzyl)-4-methyl-5-oxopyrrolidine-2-carboxylate

methyl (2R,3R,4R)-3-((tert-butyldimethylsilyl)oxy)-1-(4-methoxybenzyl)-4-methyl-4-(methylthio)-5-oxo-2-((pivaloyloxy)methyl)pyrrolidine-2-carboxylate

(5R,3R)-5-hydroxymethyl-1-(4-methoxybenzyl)-3-methyl-3-methylsulfanyl-2,4-dioxo-pyrrolidine-5-carboxylic acid methyl ester

(2R,3S)-methyl 3-((4S,5S)-3-benzyl-4-(((tert-butyldimethylsilyl)oxy)methyl)-5-isopropyloxazolidin-4-yl)-3-hydroxy-2-methylpropanoate

methyl (4S,5S)-4-((1S,2S)-1-hydroxy-2-methylbut-3-en-1-yl)-5-isopropyl-2-phenyl-4,5-dihydrooxazole-4-carboxylate