tert-butyl N-[(10R,14S)-5-[(methoxycarbonyl)amino]-10-methyl-9-oxo-16-{[2-(trimethylsilyl)ethoxy]methyl}-8,16,18- triazatricyclo[13.2.1.02'7]octadeca-1(17),2,4,6,15(18)-pentaen-14-yl]carbamate