(1S,2S,3S,4S,5R)-4-benzylamino-3-O-4-N-(oxomethylidene)-1,2-O-isopropylidene-5-((tert-butyl-dimethylsilyloxy)methyl)cyclopentane-1,2,3-triol

(1S,2S,3S,4S,5S)-4-N-benzyl-5-acetoxymethyl-7,8-isopropylidenedioxy-2-oxa-4-azabicyclo[3.3.0]oct-3-one

(1R,5R,8R)-8-benzyloxy-2-oxabicyclo[3.3.0]oct-6-en-3-one

(1R,5S,6S,7S,8S)-8-benzyloxy-6,7-isopropylidenedioxy-2-oxabicyclo[3.3.0]oct-3-ol

(1R,5R,6S,7S,8S)-8-benzyloxy-6,7-isopropylidenedioxy-2-oxabicyclo[3.3.0]oct-3-one