(2S,5R,6S)-6-[(R)-1-(tert-Butyl-dimethyl-silanyloxy)-ethyl]-3,3-dimethyl-4,4,7-trioxo-4λ6-thia-1-aza-bicyclo[3.2.0]heptane-2-carboxylic acid benzyl ester

(5R)-6ξ-((R)-1-hydroxy-ethyl)-3,3-dimethyl-7-oxo-(5rH)-4-thia-1-aza-bicyclo[3.2.0]heptane-2c-carboxylic acid benzyl ester