2-[(3aR,4R,5R,6aS)-4-Formyl-5-(tetrahydro-pyran-2-yloxy)-hexahydro-cyclopenta[b]furan-(2E)-ylidene]-hexanedioic acid dimethyl ester

(1S,5R,6R,7R)-(E)-3-(1,4-dimethoxycarbonyl-1-butylidene)-6-(3-oxo-E-1-octenyl)-7-tetrahydropyranyloxy-2-oxabicyclo<3.3.0>octane