(3R,4s,5r)-4-羟基-5-[(1s)-1-羟基-2-甲基丙基]-3-甲基-2-吡咯烷酮-5-羧酸

(1R,4R,5S)-1-((S)-1-hydroxy-2-methylpropyl)-2-(4-methoxybenzyl)-4-methyl-6-oxa-2-azabicyclo[3.2.0]heptane-3,7-dione

(4R,5S)-5-isopropyl-2-phenyl-4,5-dihydrooxazole-4-carboxylic acid methyl ester

(2R,3R,4R,1'S)-(+)-3-hydroxy-2-(1-hydroxy-2-methyl-propyl)-4-methyl-5-oxo-pyrrolidine-2-carboxylic acid methyl ester

methyl (4R,5S)-4-formyl-5-isopropyl-2-phenyl-4,5-dihydrooxazole-4-carboxylate