(2S,4S)-2-isothiocyanatomethyl-4-tritylthio-1-(allyloxycarbonyl)pyrrolidine

(2S,4S)-4-Mercapto-2-{[(thiomorpholine-4-carbothioyl)-amino]-methyl}-pyrrolidine-1-carboxylic acid allyl ester

(2S,4S)-2-{[(2-Hydroxymethyl-pyrrolidine-1-carbothioyl)-amino]-methyl}-4-mercapto-pyrrolidine-1-carboxylic acid allyl ester

(4R,5S,6S)-3-((3S,5S)-1-Allyloxycarbonyl-5-{[(thiomorpholine-4-carbothioyl)-amino]-methyl}-pyrrolidin-3-ylsulfanyl)-6-((R)-1-hydroxy-ethyl)-4-methyl-7-oxo-1-aza-bicyclo[3.2.0]hept-2-ene-2-carboxylic acid allyl ester

(4R,5S,6S)-3-((3S,5S)-1-Allyloxycarbonyl-5-{[(morpholine-4-carbothioyl)-amino]-methyl}-pyrrolidin-3-ylsulfanyl)-6-((R)-1-hydroxy-ethyl)-4-methyl-7-oxo-1-aza-bicyclo[3.2.0]hept-2-ene-2-carboxylic acid allyl ester

(4R,5S,6S)-3-((3S,5S)-1-Allyloxycarbonyl-5-{[(4-hydroxy-piperidine-1-carbothioyl)-amino]-methyl}-pyrrolidin-3-ylsulfanyl)-6-((R)-1-hydroxy-ethyl)-4-methyl-7-oxo-1-aza-bicyclo[3.2.0]hept-2-ene-2-carboxylic acid allyl ester

(4R,5S,6S)-3-((3S,5S)-1-Allyloxycarbonyl-5-{[(piperazine-1-carbothioyl)-amino]-methyl}-pyrrolidin-3-ylsulfanyl)-6-((R)-1-hydroxy-ethyl)-4-methyl-7-oxo-1-aza-bicyclo[3.2.0]hept-2-ene-2-carboxylic acid allyl ester