(1aS,3R,7bR)-3-Bromo-4-[(S)-1-(tert-butyl-dimethyl-silanyloxy)-ethyl]-1a,2,3,7b-tetrahydro-1-oxa-7-aza-cyclopropa[a]naphthalene-6-carboxylic acid methyl ester

methyl 4-acetylquinoline-2-carboxylate