3-(5-{Allyloxycarbonyl-[3-eth-(E)-ylidene-4-methyl-5-oxo-pyrrolidin-(2E)-ylidene]-methyl}-2-formyl-4-methyl-1H-pyrrol-3-yl)-propionic acid allyl ester

3-(2-Allyloxycarbonyl-ethyl)-5-{allyloxycarbonyl-[3-eth-(E)-ylidene-4-methyl-5-oxo-pyrrolidin-(2E)-ylidene]-methyl}-4-methyl-1H-pyrrole-2-carboxylic acid tert-butyl ester