4R-{2S-[2-(3S-hydroxy-7-tritylsulfanylhept-4E-enoylamino)propionylamino]-3-tritylsulfanylpropionylamino}-5R-methyl-3S-triisopropylsilanyloxyhexanoic acid

epi-4R-{2S-[2-(3R-hydroxy-7-tritylsulfanylhept-4E-enoylamino)propionylamino]-3-tritylsulfanylpropionylamino}-5R-methyl-3S-triisopropylsilanyloxyhexanoic acid 2,2,2-trichloroethyl ester