(Z)-(S)-2-Mercapto-5-(tetrahydro-pyran-2-yloxy)-hex-2-enoic acid methyl ester

(S)-2-Benzyloxycarbonylamino-3-iodo-propionic acid benzhydryl ester

(R)-2-Benzyloxycarbonylamino-3-hydroxy-propionic acid benzhydryl ester

(Z)-(S)-2-((S)-2-Benzhydryloxycarbonyl-2-benzyloxycarbonylamino-ethylsulfanyl)-5-(tetrahydro-pyran-2-yloxy)-hex-2-enoic acid methyl ester

N,N'-bis(carbobenzyloxy)-L-cystine di-tert-butyl ester