allyl (2S,3aS,6R,7aS)-2-(((S)-6-((benzyloxy)carbonyl)-5-imino-13,13,14,14-tetramethyl-3-oxo-1-phenyl-2,12-dioxa-4,6-diaza-13-silapentadecan-10-yl)carbamoyl)-6-((tert-butyldimethylsilyl)oxy)octahydro-1H-indole-1-carboxylate