(S)-3-(tert-Butyl-dimethyl-silanyloxy)-1-((1S,5R,7R)-10,10-dimethyl-3,3-dioxo-3λ6-thia-4-aza-tricyclo[5.2.1.01,5]dec-4-yl)-3-quinolin-7-yl-propan-1-one