(Z)-8-ethyl-3-(2-methoxycarbonylethyl)-2,7,9-trimethyl-(10H)-dipyrrin-1-one

5-[Allyloxycarbonyl-(triphenyl-λ5-phosphanylidene)-methyl]-3-(2-methoxycarbonyl-ethyl)-4-methyl-1H-pyrrole-2-carboxylic acid tert-butyl ester