(2R,3R)-3-Benzylamino-3-((S)-2,2-dimethyl-[1,3]dioxolan-4-yl)-propane-1,2-diol

[(1R,2R)-1-((S)-2,2-Dimethyl-[1,3]dioxolan-4-yl)-2,3-dihydroxy-propyl]-carbamic acid tert-butyl ester

(R)-1-Benzyl-4-((S)-2,2-dimethyl-[1,3]dioxolan-4-yl)-azetidin-2-one

(3R,4R)-1-benzyl-4-formyl-3-mesyloxyazetidin-2-one

Methanesulfonic acid (2S,3R)-1-benzyl-2-((S)-1,2-dihydroxy-ethyl)-4-oxo-azetidin-3-yl ester