(2S,5R,6R)-6-Carbamoylmethyl-3,3-dimethyl-4,7-dioxo-4λ4-thia-1-aza-bicyclo[3.2.0]heptane-2-carboxylic acid benzyl ester

6-α-methoxymonotriflamide

(2S,5R,6R)-3,3-Dimethyl-7-oxo-6-trifluoromethanesulfonylamino-4-thia-1-aza-bicyclo[3.2.0]heptane-2-carboxylic acid benzyl ester

(2S,5R)-3,3-Dimethyl-7-oxo-6-[(E)-trifluoromethanesulfonylimino]-4-thia-1-aza-bicyclo[3.2.0]heptane-2-carboxylic acid benzyl ester

(2S,3R,5R,6R)-6-Carbamoylmethyl-3-chloromethyl-3-methyl-4,4,7-trioxo-4λ6-thia-1-aza-bicyclo[3.2.0]heptane-2-carboxylic acid benzyl ester