(2S,3S)-2-((R)-2-Benzyloxy-1-hydroxy-ethyl)-1-((1S,5R,7R)-10,10-dimethyl-3,3-dioxo-3λ6-thia-4-aza-tricyclo[5.2.1.01,5]dec-4-yl)-3-methyl-pentan-1-one