Intermediates in the Synthesis of Daphniphyllum Alkaloids. I. A Tetracyclic Oxygen Analogue

In methyl (3S,5S,6S,10R,11R)-2-bromo-3,6-epoxy-8-isopropyl-5-methyl-9-oxotricyclo[9.3.0.0^5,10]tetradeca-1,7-diene-10-carboxylate, C₂₀H₂₅BrO₄, the seven-membered ring is half-chair shaped, the six-membered ring adopts a boat conformation and the five-membered rings both adopt envelope conformations. The molecule adopts an overall hemispherical conformation.