3-(2-Methoxycarbonyl-ethyl)-4-methyl-5-((3aR,6aS)-3a-methyl-2,5-dioxo-hexahydro-furo[2,3-b]pyrrol-6a-ylmethyl)-1H-pyrrole-2-carboxylic acid tert-butyl ester

(2S,3S)-3-Methoxycarbonylmethyl-3-methyl-5-oxo-tetrahydro-furan-2-carboxylic acid benzyl ester