(1[alpha],3[alpha],11[alpha])-2,2,11-Trimethyl-14-oxatetracyclo[6.5.0.1^7,11.0^3,8]tetradec-6-ene-5,9-dione

The title compound, C₁₆H₂₀O₃, was prepared by the photolysis of 7-hydroxy-2-methyl-2-(4-methyl-3-pentenyl)-4-chromanone. The H7 and H9 atoms are in an [alpha] configuration. The cyclobutane ring is non-planar, the cyclohexenone ring has a half-chair conformation, the pyranone ring has a sofa conformation and the cycloheptanone ring has a boat conformation. The groups of atoms C11, C12, C13, O14 and C12, C13, O14, C4 are both planar.

-1