(1S,3R,7S,8S,8aR)-8-((3R,5R)-7-(butyl(methyl)amino)-3,5-bis((tert-butyldimethylsilyl)oxy)-7-oxoheptyl)-3,7-dimethyl-1,2,3,7,8,8a-hexahydronaphthalen-1-yl 2-methylbutanoate