(2R,3S)-3-Hydroxy-2-((S)-1-hydroxy-2-methyl-propyl)-4,4-dimethyl-5-oxo-pyrrolidine-2-carboxylic acid

(4R,5S)-5-Isopropyl-2-oxo-2λ4-[1,3,2]dioxathiolane-4-carboxylic acid methyl ester

(2S,3S)-2-azido-3-hydroxy-4-methylpentanoic acid methyl ester

(1S,7aR)-7a-(tert-Butyl-dimethyl-silanyloxymethyl)-1-isopropyl-6,6-dimethyl-dihydro-pyrrolo[1,2-c]oxazole-5,7-dione

(4S,5S)-4-methoxycarbonyl-5-(1-methylethyl)-2-phenyl-1,3-oxazolidine

(4S,5S)-4-((S)-2-Ethoxycarbonyl-1-hydroxy-2-methyl-propyl)-5-isopropyl-2-phenyl-4,5-dihydro-oxazole-4-carboxylic acid methyl ester

(1S,7S,7aS)-7-Hydroxy-7a-hydroxymethyl-1-isopropyl-6,6-dimethyl-tetrahydro-pyrrolo[1,2-c]oxazol-5-one

(2S,3S)-2-((S)-1-Benzoyloxy-2-methyl-propyl)-3-hydroxy-4,4-dimethyl-5-oxo-pyrrolidine-2-carboxylic acid methyl ester