A Novel Tricyclic Cyclobutanone Ketal

Methyl (±)-(1α,1aα,3aα,6aα,6 bα)-1a-ethenyl-1,1a,2,3a,4,5,6a,6b-octahydro-6a- methoxy-2,2-dimethyl-3,6-dioxacyclobut[cd]indene-1-carboxylate, C₁₅H₂₂O₅, adopts a hemispherical conformation with the methoxy, methoxycarbonyl and vinyl groups pointing outward from the hemisphere. The tetrahydropyran ring is in a chair conformation and the tetrahydrofuran ring is in an envelope conformation.

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