((2S,3S)-2-Hydroxymethyl-5-oxo-pyrrolidin-3-ylmethyl)-carbamic acid benzyl ester

((2S,3R)-2-Hydroxymethyl-5-oxo-pyrrolidin-3-ylmethyl)-carbamic acid benzyl ester

(2R,5S,6S)-6-(carbamoylmethyl)-8-oxo-2-phenyl-1-aza-3-oxa-bicyclo[3.3.0]octane

(2R,5S,6S,11R)-8,9-dimethyl-12-oxo-2-phenyl-1-aza-3-oxa-tricyclo[7.3.01,5.06,11]dodec-8-ene

(2R,5S,6S,11S)-11-carboxyl-8,9-dimethyl-12-oxo-2-phenyl-1-aza-3-oxa-tricyclo[7.3.01,5.06,11]dodec-8-ene