Total Synthesis of (−)-Ophiodilactone A and (−)-Ophiodilactone B.

The first asymmetric total synthesis of (−)-ophiodilactone A and (−)-ophiodilactone B, isolated from the ophiuroid (Ophiocoma scolopendrina), is reported. The key features of the synthesis include the highly stereocontrolled construction of the structurally congested γ-lactone/δ-lactone skeleton through an asymmetric epoxidation, diastereoselective iodolactonization, and intramolecular epoxide-opening with a carboxylic acid, and biomimetic radical cyclization of ophiodilactone A to ophiodilactone B. [ABSTRACT FROM AUTHOR]