Intermediates in the Synthesis of Forskolin. I

In 4-acetyl-3,4-epoxy-3,6,6,8b-tetramethyl-2a,3,4,6,7,8,8a,8b-octahydro- 2H-naphtho[1,8a,8-bc]furan-2-one, C₁₇H₂₂O₄, the saturated ring (A) adopts a chair conformation, the cyclohexene ring (B) a distorted half-chair conformation and the furan ring an envelope conformation. The lactone and the epoxy moieties are trans to each other.

-1