2-Azabicyclo[2.2.1]heptane-2-carboxylic acid, 3-[6-[9,9-difluoro-7-[2-[(6S)-5-[(2S)-2-[(methoxycarbonyl)amino]-3-methyl-1-oxobutyl]-5-azaspiro[2.4]hept-6-yl]-1H-imidazol-5-yl]-9H-fluoren-2-yl]-1H-benzimidazol-2-yl]-, 1,1-dimethylethyl ester, (1R,3S,4S)-