(3S,4R)-3-((S)-sec-Butyl)-4-hydroxymethyl-oxetan-2-one

(3S,4R)-3-((S)-sec-butyl)-4-oxooxetane-2-carboxylic acid

(2S)-[(2S)-benzyloxycarbonylaminopropionylamino]-5-{[(3S)-((1S)-methylpropyl)-4-oxooxetane-(2R)-carbonyl]amino}pentanoic acid benzyl ester

(2S,3S)-2-((R)-2-Benzyloxy-1-hydroxy-ethyl)-3-methyl-pentanal

(3S,4R)-4-benzyloxymethyl-3-((S)-sec-butyl)oxetan-2-one