2-((R)-2-{(2S,3S)-3-[(R)-1-(tert-Butyl-dimethyl-silanyloxy)-ethyl]-4-oxo-azetidin-2-yl}-propionylsulfanylmethyl)-malonic acid diethyl ester

(2S,5R,6S,7S)-7-[(R)-1-(tert-Butyl-dimethyl-silanyloxy)-ethyl]-5-methyl-4,8-dioxo-3-thia-1-aza-bicyclo[4.2.0]octane-2-carboxylic acid 2,2-dimethyl-propionyloxymethyl ester

(4R,5R,6S)-6-[(R)-1-(tert-Butyl-dimethyl-silanyloxy)-ethyl]-3-(diphenoxy-phosphoryloxy)-4-methyl-7-oxo-1-aza-bicyclo[3.2.0]hept-2-ene-2-carboxylic acid allyl ester

pivaloyloxymethyl (1R,5R,6S)-6-[(1R)-1-(tert-butyldimethylsilyloxy)ethyl]-2-(diphenylphosphoryloxy)-1-methylcarbapen-2-em-3-carboxylate