(2S,4S)-2-[(4-hydroxy-3-ethoxycarbonylpyrrolidinyl)carbonyl]-4-tritylthio-1-(allyloxycarbonyl)pyrrolidine

(2S,4S)-2-[(1-methoxyimino-2-ethoxycarbonyl)ethyl]-4-tritylthio-1-(allyloxycarbonyl)pyrrolidine

allyl (2S,4S)-2-((2-((N,N-dimethylsulfamoyl)amino)ethyl)carbamoyl)-4-mercaptopyrrolidine-1-carboxylate

(2S,4S)-2-(3-Hydroxy-pyrrolidine-1-carbonyl)-4-tritylsulfanyl-pyrrolidine-1-carboxylic acid allyl ester

(2S,4S)-2-[(2-azidoethyl)carbamoyl]-4-tritylthio-1-(allyloxycarbonyl)pyrrolidine