(E)-4-{(2R,3S)-1-(tert-Butyl-dimethyl-silanyl)-3-[(R)-1-(tert-butyl-dimethyl-silanyloxy)-ethyl]-4-oxo-azetidin-2-yl}-but-2-enal

(3S,4R)-1-(tert-Butyl-dimethyl-silanyl)-3-[(R)-1-(tert-butyl-dimethyl-silanyloxy)-ethyl]-4-((E)-4-iodo-but-2-enyl)-azetidin-2-one

(3S,4S)-1-(tert-Butyl-dimethyl-silanyl)-3-[(R)-1-(tert-butyl-dimethyl-silanyloxy)-ethyl]-4-iodomethyl-azetidin-2-one

<3S-<3α(S*),4β>>-3-(1-t-butyldimethylsilyloxyethyl)-4-iodomethyl-2-azetidinone