Dimethyl 11,13-dimethyl-16-[1,2-bis-(methoxycarbonyl)ethenyl]-12-oxo-16,17- dioxa-18-azahexacyclo-[7.5.1.11,4.16,9.1 10,14.05,15]octadeca-2,7-diene-2,3-dicarboxylate

The title compound, C27H29NO11, is a product of the tandem domino Diels-Alder reaction. The mol-ecule comprises a fused hexa-cyclic system containing four five-membered rings (two dihydro-furan and two tetra-hydro-furan) in the usual envelope conformations and two six-membered rings (tetra-hydro-pyridinone and piperidine) adopting slightly flattened boat and chair conformations, respectively. The dispositions of the carboxyl-ate substituents relative to each other are determined by both steric reasons and inter-molecular C - H⋯O hydrogen bonding and attractive anti-parallel C=O⋯C=O inter-actions [C⋯O = 2.995 (2) Å].