(1-{1-Cyclohexyl-2-[4-methanesulfonyl-6-(1,2,3,4-tetrahydro-naphthalen-1-ylcarbamoyl)-hexahydro-pyrrolo[3,2-b]pyrrol-1-yl]-2-oxo-ethylcarbamoyl}-ethyl)-methyl-carbamic acid tert-butyl ester