2-((2R,3R)-2-Ethyl-5-oxo-tetrahydro-furan-3-yl)-3-oxo-propionic acid methyl ester

(3R,4R)-4-Hydroxy-3-{[2-(1H-indol-3-yl)-ethylcarbamoyl]-methyl}-2-[1-methoxy-meth-(E)-ylidene]-hexanoic acid methyl ester

(3R,4R)-4-Benzyloxycarbonyloxy-2-[1-methoxy-meth-(E)-ylidene]-3-[(S)-1-(2,3,4,9-tetrahydro-1H-β-carbolin-1-yl)methyl]-hexanoic acid methyl ester